diff options
Diffstat (limited to 'doc/src/sgml/ref/psql-ref.sgml')
| -rw-r--r-- | doc/src/sgml/ref/psql-ref.sgml | 5187 |
1 files changed, 5187 insertions, 0 deletions
diff --git a/doc/src/sgml/ref/psql-ref.sgml b/doc/src/sgml/ref/psql-ref.sgml new file mode 100644 index 0000000..d0bd119 --- /dev/null +++ b/doc/src/sgml/ref/psql-ref.sgml @@ -0,0 +1,5187 @@ +<!-- +doc/src/sgml/ref/psql-ref.sgml +PostgreSQL documentation +--> + +<refentry id="app-psql"> + <indexterm zone="app-psql"> + <primary>psql</primary> + </indexterm> + + <refmeta> + <refentrytitle><application>psql</application></refentrytitle> + <manvolnum>1</manvolnum> + <refmiscinfo>Application</refmiscinfo> + </refmeta> + + <refnamediv> + <refname><application>psql</application></refname> + <refpurpose> + <productname>PostgreSQL</productname> interactive terminal + </refpurpose> + </refnamediv> + + <refsynopsisdiv> + <cmdsynopsis> + <command>psql</command> + <arg rep="repeat"><replaceable class="parameter">option</replaceable></arg> + <arg choice="opt"><replaceable class="parameter">dbname</replaceable> + <arg choice="opt"><replaceable class="parameter">username</replaceable></arg></arg> + </cmdsynopsis> + </refsynopsisdiv> + + <refsect1> + <title>Description</title> + + <para> + <application>psql</application> is a terminal-based front-end to + <productname>PostgreSQL</productname>. It enables you to type in + queries interactively, issue them to + <productname>PostgreSQL</productname>, and see the query results. + Alternatively, input can be from a file or from command line + arguments. In addition, <application>psql</application> provides a + number of meta-commands and various shell-like features to + facilitate writing scripts and automating a wide variety of tasks. + </para> + </refsect1> + + <refsect1 id="r1-app-psql-3"> + <title>Options</title> + + <variablelist> + <varlistentry> + <term><option>-a</option></term> + <term><option>--echo-all</option></term> + <listitem> + <para> + Print all nonempty input lines to standard output as they are read. + (This does not apply to lines read interactively.) This is + equivalent to setting the variable <varname>ECHO</varname> to + <literal>all</literal>. + </para> + </listitem> + </varlistentry> + + <varlistentry> + <term><option>-A</option></term> + <term><option>--no-align</option></term> + <listitem> + <para> + Switches to unaligned output mode. (The default output mode is + <literal>aligned</literal>.) This is equivalent to + <command>\pset format unaligned</command>. + </para> + </listitem> + </varlistentry> + + <varlistentry> + <term><option>-b</option></term> + <term><option>--echo-errors</option></term> + <listitem> + <para> + Print failed SQL commands to standard error output. This is + equivalent to setting the variable <varname>ECHO</varname> to + <literal>errors</literal>. + </para> + </listitem> + </varlistentry> + + <varlistentry> + <term><option>-c <replaceable class="parameter">command</replaceable></option></term> + <term><option>--command=<replaceable class="parameter">command</replaceable></option></term> + <listitem> + <para> + Specifies that <application>psql</application> is to execute the given + command string, <replaceable class="parameter">command</replaceable>. + This option can be repeated and combined in any order with + the <option>-f</option> option. When either <option>-c</option> + or <option>-f</option> is specified, <application>psql</application> + does not read commands from standard input; instead it terminates + after processing all the <option>-c</option> and <option>-f</option> + options in sequence. + </para> + <para> + <replaceable class="parameter">command</replaceable> must be either + a command string that is completely parsable by the server (i.e., + it contains no <application>psql</application>-specific features), + or a single backslash command. Thus you cannot mix + <acronym>SQL</acronym> and <application>psql</application> + meta-commands within a <option>-c</option> option. To achieve that, + you could use repeated <option>-c</option> options or pipe the string + into <application>psql</application>, for example: +<programlisting> +psql -c '\x' -c 'SELECT * FROM foo;' +</programlisting> + or +<programlisting> +echo '\x \\ SELECT * FROM foo;' | psql +</programlisting> + (<literal>\\</literal> is the separator meta-command.) + </para> + <para> + Each <acronym>SQL</acronym> command string passed + to <option>-c</option> is sent to the server as a single request. + Because of this, the server executes it as a single transaction even + if the string contains multiple <acronym>SQL</acronym> commands, + unless there are explicit <command>BEGIN</command>/<command>COMMIT</command> + commands included in the string to divide it into multiple + transactions. (See <xref linkend="protocol-flow-multi-statement"/> + for more details about how the server handles multi-query strings.) + </para> + <para> + If having several commands executed in one transaction is not desired, + use repeated <option>-c</option> commands or feed multiple commands to + <application>psql</application>'s standard input, + either using <application>echo</application> as illustrated above, or + via a shell here-document, for example: +<programlisting> +psql <<EOF +\x +SELECT * FROM foo; +EOF +</programlisting></para> + </listitem> + </varlistentry> + + <varlistentry> + <term><option>--csv</option></term> + <listitem> + <para> + Switches to <acronym>CSV</acronym> (Comma-Separated Values) output + mode. This is equivalent to <command>\pset format csv</command>. + </para> + </listitem> + </varlistentry> + + <varlistentry> + <term><option>-d <replaceable class="parameter">dbname</replaceable></option></term> + <term><option>--dbname=<replaceable class="parameter">dbname</replaceable></option></term> + <listitem> + <para> + Specifies the name of the database to connect to. This is + equivalent to specifying <replaceable + class="parameter">dbname</replaceable> as the first non-option + argument on the command line. The <replaceable>dbname</replaceable> + can be a <link linkend="libpq-connstring">connection string</link>. + If so, connection string parameters will override any conflicting + command line options. + </para> + </listitem> + </varlistentry> + + <varlistentry> + <term><option>-e</option></term> + <term><option>--echo-queries</option></term> + <listitem> + <para> + Copy all SQL commands sent to the server to standard output as well. + This is equivalent + to setting the variable <varname>ECHO</varname> to + <literal>queries</literal>. + </para> + </listitem> + </varlistentry> + + <varlistentry> + <term><option>-E</option></term> + <term><option>--echo-hidden</option></term> + <listitem> + <para> + Echo the actual queries generated by <command>\d</command> and other backslash + commands. You can use this to study <application>psql</application>'s + internal operations. This is equivalent to + setting the variable <varname>ECHO_HIDDEN</varname> to <literal>on</literal>. + </para> + </listitem> + </varlistentry> + + <varlistentry> + <term><option>-f <replaceable class="parameter">filename</replaceable></option></term> + <term><option>--file=<replaceable class="parameter">filename</replaceable></option></term> + <listitem> + <para> + Read commands from the + file <replaceable class="parameter">filename</replaceable>, + rather than standard input. + This option can be repeated and combined in any order with + the <option>-c</option> option. When either <option>-c</option> + or <option>-f</option> is specified, <application>psql</application> + does not read commands from standard input; instead it terminates + after processing all the <option>-c</option> and <option>-f</option> + options in sequence. + Except for that, this option is largely equivalent to the + meta-command <command>\i</command>. + </para> + + <para> + If <replaceable>filename</replaceable> is <literal>-</literal> + (hyphen), then standard input is read until an EOF indication + or <command>\q</command> meta-command. This can be used to intersperse + interactive input with input from files. Note however that Readline + is not used in this case (much as if <option>-n</option> had been + specified). + </para> + + <para> + Using this option is subtly different from writing <literal>psql + < <replaceable + class="parameter">filename</replaceable></literal>. In general, + both will do what you expect, but using <literal>-f</literal> + enables some nice features such as error messages with line + numbers. There is also a slight chance that using this option will + reduce the start-up overhead. On the other hand, the variant using + the shell's input redirection is (in theory) guaranteed to yield + exactly the same output you would have received had you entered + everything by hand. + </para> + </listitem> + </varlistentry> + + <varlistentry> + <term><option>-F <replaceable class="parameter">separator</replaceable></option></term> + <term><option>--field-separator=<replaceable class="parameter">separator</replaceable></option></term> + <listitem> + <para> + Use <replaceable class="parameter">separator</replaceable> as the + field separator for unaligned output. This is equivalent to + <command>\pset fieldsep</command> or <command>\f</command>. + </para> + </listitem> + </varlistentry> + + <varlistentry> + <term><option>-h <replaceable class="parameter">hostname</replaceable></option></term> + <term><option>--host=<replaceable class="parameter">hostname</replaceable></option></term> + <listitem> + <para> + Specifies the host name of the machine on which the + server is running. If the value begins + with a slash, it is used as the directory for the Unix-domain + socket. + </para> + </listitem> + </varlistentry> + + <varlistentry> + <term><option>-H</option></term> + <term><option>--html</option></term> + <listitem> + <para> + Switches to <acronym>HTML</acronym> output mode. This is + equivalent to <command>\pset format html</command> or the + <command>\H</command> command. + </para> + </listitem> + </varlistentry> + + <varlistentry> + <term><option>-l</option></term> + <term><option>--list</option></term> + <listitem> + <para> + List all available databases, then exit. Other non-connection + options are ignored. This is similar to the meta-command + <command>\list</command>. + </para> + + <para> + When this option is used, <application>psql</application> will connect + to the database <literal>postgres</literal>, unless a different database + is named on the command line (option <option>-d</option> or non-option + argument, possibly via a service entry, but not via an environment + variable). + </para> + </listitem> + </varlistentry> + + <varlistentry> + <term><option>-L <replaceable class="parameter">filename</replaceable></option></term> + <term><option>--log-file=<replaceable class="parameter">filename</replaceable></option></term> + <listitem> + <para> + Write all query output into file <replaceable + class="parameter">filename</replaceable>, in addition to the + normal output destination. + </para> + </listitem> + </varlistentry> + + <varlistentry> + <term><option>-n</option></term> + <term><option>--no-readline</option></term> + <listitem> + <para> + Do not use <application>Readline</application> for line editing and + do not use the command history (see + <xref linkend="app-psql-readline"/> below). + </para> + </listitem> + </varlistentry> + + <varlistentry> + <term><option>-o <replaceable class="parameter">filename</replaceable></option></term> + <term><option>--output=<replaceable class="parameter">filename</replaceable></option></term> + <listitem> + <para> + Put all query output into file <replaceable + class="parameter">filename</replaceable>. This is equivalent to + the command <command>\o</command>. + </para> + </listitem> + </varlistentry> + + <varlistentry> + <term><option>-p <replaceable class="parameter">port</replaceable></option></term> + <term><option>--port=<replaceable class="parameter">port</replaceable></option></term> + <listitem> + <para> + Specifies the TCP port or the local Unix-domain + socket file extension on which the server is listening for + connections. Defaults to the value of the <envar>PGPORT</envar> + environment variable or, if not set, to the port specified at + compile time, usually 5432. + </para> + </listitem> + </varlistentry> + + <varlistentry> + <term><option>-P <replaceable class="parameter">assignment</replaceable></option></term> + <term><option>--pset=<replaceable class="parameter">assignment</replaceable></option></term> + <listitem> + <para> + Specifies printing options, in the style of + <command>\pset</command>. Note that here you + have to separate name and value with an equal sign instead of a + space. For example, to set the output format to <application>LaTeX</application>, you could write + <literal>-P format=latex</literal>. + </para> + </listitem> + </varlistentry> + + <varlistentry> + <term><option>-q</option></term> + <term><option>--quiet</option></term> + <listitem> + <para> + Specifies that <application>psql</application> should do its work + quietly. By default, it prints welcome messages and various + informational output. If this option is used, none of this + happens. This is useful with the <option>-c</option> option. + This is equivalent to setting the variable <varname>QUIET</varname> + to <literal>on</literal>. + </para> + </listitem> + </varlistentry> + + <varlistentry> + <term><option>-R <replaceable class="parameter">separator</replaceable></option></term> + <term><option>--record-separator=<replaceable class="parameter">separator</replaceable></option></term> + <listitem> + <para> + Use <replaceable class="parameter">separator</replaceable> as the + record separator for unaligned output. This is equivalent to + <command>\pset recordsep</command>. + </para> + </listitem> + </varlistentry> + + <varlistentry> + <term><option>-s</option></term> + <term><option>--single-step</option></term> + <listitem> + <para> + Run in single-step mode. That means the user is prompted before + each command is sent to the server, with the option to cancel + execution as well. Use this to debug scripts. + </para> + </listitem> + </varlistentry> + + <varlistentry> + <term><option>-S</option></term> + <term><option>--single-line</option></term> + <listitem> + <para> + Runs in single-line mode where a newline terminates an SQL command, as a + semicolon does. + </para> + + <note> + <para> + This mode is provided for those who insist on it, but you are not + necessarily encouraged to use it. In particular, if you mix + <acronym>SQL</acronym> and meta-commands on a line the order of + execution might not always be clear to the inexperienced user. + </para> + </note> + </listitem> + </varlistentry> + + <varlistentry> + <term><option>-t</option></term> + <term><option>--tuples-only</option></term> + <listitem> + <para> + Turn off printing of column names and result row count footers, + etc. This is equivalent to <command>\t</command> or + <command>\pset tuples_only</command>. + </para> + </listitem> + </varlistentry> + + <varlistentry> + <term><option>-T <replaceable class="parameter">table_options</replaceable></option></term> + <term><option>--table-attr=<replaceable class="parameter">table_options</replaceable></option></term> + <listitem> + <para> + Specifies options to be placed within the + <acronym>HTML</acronym> <sgmltag>table</sgmltag> tag. See + <command>\pset tableattr</command> for details. + </para> + </listitem> + </varlistentry> + + <varlistentry> + <term><option>-U <replaceable class="parameter">username</replaceable></option></term> + <term><option>--username=<replaceable class="parameter">username</replaceable></option></term> + <listitem> + <para> + Connect to the database as the user <replaceable + class="parameter">username</replaceable> instead of the default. + (You must have permission to do so, of course.) + </para> + </listitem> + </varlistentry> + + <varlistentry> + <term><option>-v <replaceable class="parameter">assignment</replaceable></option></term> + <term><option>--set=<replaceable class="parameter">assignment</replaceable></option></term> + <term><option>--variable=<replaceable class="parameter">assignment</replaceable></option></term> + <listitem> + <para> + Perform a variable assignment, like the <command>\set</command> + meta-command. Note that you must separate name and value, if + any, by an equal sign on the command line. To unset a variable, + leave off the equal sign. To set a variable with an empty value, + use the equal sign but leave off the value. These assignments are + done during command line processing, so variables that reflect + connection state will get overwritten later. + </para> + </listitem> + </varlistentry> + + <varlistentry> + <term><option>-V</option></term> + <term><option>--version</option></term> + <listitem> + <para> + Print the <application>psql</application> version and exit. + </para> + </listitem> + </varlistentry> + + <varlistentry> + <term><option>-w</option></term> + <term><option>--no-password</option></term> + <listitem> + <para> + Never issue a password prompt. If the server requires password + authentication and a password is not available from other sources + such as a <filename>.pgpass</filename> file, the connection + attempt will fail. This option can be useful in batch jobs and + scripts where no user is present to enter a password. + </para> + + <para> + Note that this option will remain set for the entire session, + and so it affects uses of the meta-command + <command>\connect</command> as well as the initial connection attempt. + </para> + </listitem> + </varlistentry> + + <varlistentry> + <term><option>-W</option></term> + <term><option>--password</option></term> + <listitem> + <para> + Force <application>psql</application> to prompt for a + password before connecting to a database, even if the password will + not be used. + </para> + + <para> + If the server requires password authentication and a password is not + available from other sources such as a <filename>.pgpass</filename> + file, <application>psql</application> will prompt for a + password in any case. However, <application>psql</application> + will waste a connection attempt finding out that the server wants a + password. In some cases it is worth typing <option>-W</option> to avoid + the extra connection attempt. + </para> + + <para> + Note that this option will remain set for the entire session, + and so it affects uses of the meta-command + <command>\connect</command> as well as the initial connection attempt. + </para> + </listitem> + </varlistentry> + + <varlistentry> + <term><option>-x</option></term> + <term><option>--expanded</option></term> + <listitem> + <para> + Turn on the expanded table formatting mode. This is equivalent to + <command>\x</command> or <command>\pset expanded</command>. + </para> + </listitem> + </varlistentry> + + <varlistentry> + <term><option>-X,</option></term> + <term><option>--no-psqlrc</option></term> + <listitem> + <para> + Do not read the start-up file (neither the system-wide + <filename>psqlrc</filename> file nor the user's + <filename>~/.psqlrc</filename> file). + </para> + </listitem> + </varlistentry> + + <varlistentry> + <term><option>-z</option></term> + <term><option>--field-separator-zero</option></term> + <listitem> + <para> + Set the field separator for unaligned output to a zero byte. This is + equivalent to <command>\pset fieldsep_zero</command>. + </para> + </listitem> + </varlistentry> + + <varlistentry> + <term><option>-0</option></term> + <term><option>--record-separator-zero</option></term> + <listitem> + <para> + Set the record separator for unaligned output to a zero byte. This is + useful for interfacing, for example, with <literal>xargs -0</literal>. + This is equivalent to <command>\pset recordsep_zero</command>. + </para> + </listitem> + </varlistentry> + + <varlistentry> + <term><option>-1</option></term> + <term><option>--single-transaction</option></term> + <listitem> + <para> + This option can only be used in combination with one or more + <option>-c</option> and/or <option>-f</option> options. It causes + <application>psql</application> to issue a <command>BEGIN</command> command + before the first such option and a <command>COMMIT</command> command after + the last one, thereby wrapping all the commands into a single + transaction. If any of the commands fails and the variable + <varname>ON_ERROR_STOP</varname> was set, a + <command>ROLLBACK</command> command is sent instead. This ensures that + either all the commands complete successfully, or no changes are + applied. + </para> + + <para> + If the commands themselves + contain <command>BEGIN</command>, <command>COMMIT</command>, + or <command>ROLLBACK</command>, this option will not have the desired + effects. Also, if an individual command cannot be executed inside a + transaction block, specifying this option will cause the whole + transaction to fail. + </para> + </listitem> + </varlistentry> + + <varlistentry> + <term><option>-?</option></term> + <term><option>--help[=<replaceable class="parameter">topic</replaceable>]</option></term> + <listitem> + <para> + Show help about <application>psql</application> and exit. The optional + <replaceable class="parameter">topic</replaceable> parameter (defaulting + to <literal>options</literal>) selects which part of <application>psql</application> is + explained: <literal>commands</literal> describes <application>psql</application>'s + backslash commands; <literal>options</literal> describes the command-line + options that can be passed to <application>psql</application>; + and <literal>variables</literal> shows help about <application>psql</application> configuration + variables. + </para> + </listitem> + </varlistentry> + + </variablelist> + </refsect1> + + + <refsect1> + <title>Exit Status</title> + + <para> + <application>psql</application> returns 0 to the shell if it + finished normally, 1 if a fatal error of its own occurs (e.g., out of memory, + file not found), 2 if the connection to the server went bad + and the session was not interactive, and 3 if an error occurred in a + script and the variable <varname>ON_ERROR_STOP</varname> was set. + </para> + </refsect1> + + + <refsect1> + <title>Usage</title> + + <refsect2 id="r2-app-psql-connecting"> + <title>Connecting to a Database</title> + + <para> + <application>psql</application> is a regular + <productname>PostgreSQL</productname> client application. In order + to connect to a database you need to know the name of your target + database, the host name and port number of the server, and what user + name you want to connect as. <application>psql</application> can be + told about those parameters via command line options, namely + <option>-d</option>, <option>-h</option>, <option>-p</option>, and + <option>-U</option> respectively. If an argument is found that does + not belong to any option it will be interpreted as the database name + (or the user name, if the database name is already given). Not all + of these options are required; there are useful defaults. If you omit the host + name, <application>psql</application> will connect via a Unix-domain socket + to a server on the local host, or via TCP/IP to <literal>localhost</literal> on + machines that don't have Unix-domain sockets. The default port number is + determined at compile time. + Since the database server uses the same default, you will not have + to specify the port in most cases. The default user name is your + operating-system user name, as is the default database name. + Note that you cannot + just connect to any database under any user name. Your database + administrator should have informed you about your access rights. + </para> + + <para> + When the defaults aren't quite right, you can save yourself + some typing by setting the environment variables + <envar>PGDATABASE</envar>, <envar>PGHOST</envar>, + <envar>PGPORT</envar> and/or <envar>PGUSER</envar> to appropriate + values. (For additional environment variables, see <xref + linkend="libpq-envars"/>.) It is also convenient to have a + <filename>~/.pgpass</filename> file to avoid regularly having to type in + passwords. See <xref linkend="libpq-pgpass"/> for more information. + </para> + + <para> + An alternative way to specify connection parameters is in a + <parameter>conninfo</parameter> string or + a <acronym>URI</acronym>, which is used instead of a database + name. This mechanism give you very wide control over the + connection. For example: +<programlisting> +$ <userinput>psql "service=myservice sslmode=require"</userinput> +$ <userinput>psql postgresql://dbmaster:5433/mydb?sslmode=require</userinput> +</programlisting> + This way you can also use <acronym>LDAP</acronym> for connection + parameter lookup as described in <xref linkend="libpq-ldap"/>. + See <xref linkend="libpq-paramkeywords"/> for more information on all the + available connection options. + </para> + + <para> + If the connection could not be made for any reason (e.g., insufficient + privileges, server is not running on the targeted host, etc.), + <application>psql</application> will return an error and terminate. + </para> + + <para> + If both standard input and standard output are a + terminal, then <application>psql</application> sets the client + encoding to <quote>auto</quote>, which will detect the + appropriate client encoding from the locale settings + (<envar>LC_CTYPE</envar> environment variable on Unix systems). + If this doesn't work out as expected, the client encoding can be + overridden using the environment + variable <envar>PGCLIENTENCODING</envar>. + </para> + </refsect2> + + <refsect2 id="r2-app-psql-4"> + <title>Entering SQL Commands</title> + + <para> + In normal operation, <application>psql</application> provides a + prompt with the name of the database to which + <application>psql</application> is currently connected, followed by + the string <literal>=></literal>. For example: +<programlisting> +$ <userinput>psql testdb</userinput> +psql (&version;) +Type "help" for help. + +testdb=> +</programlisting> + </para> + + <para> + At the prompt, the user can type in <acronym>SQL</acronym> commands. + Ordinarily, input lines are sent to the server when a + command-terminating semicolon is reached. An end of line does not + terminate a command. Thus commands can be spread over several lines for + clarity. If the command was sent and executed without error, the results + of the command are displayed on the screen. + </para> + + <para> + If untrusted users have access to a database that has not adopted a + <link linkend="ddl-schemas-patterns">secure schema usage pattern</link>, + begin your session by removing publicly-writable schemas + from <varname>search_path</varname>. One can + add <literal>options=-csearch_path=</literal> to the connection string or + issue <literal>SELECT pg_catalog.set_config('search_path', '', + false)</literal> before other SQL commands. This consideration is not + specific to <application>psql</application>; it applies to every interface + for executing arbitrary SQL commands. + </para> + + <para> + Whenever a command is executed, <application>psql</application> also polls + for asynchronous notification events generated by + <link linkend="sql-listen"><command>LISTEN</command></link> and + <link linkend="sql-notify"><command>NOTIFY</command></link>. + </para> + + <para> + While C-style block comments are passed to the server for + processing and removal, SQL-standard comments are removed by + <application>psql</application>. + </para> + </refsect2> + + <refsect2 id="app-psql-meta-commands"> + <title>Meta-Commands</title> + + <para> + Anything you enter in <application>psql</application> that begins + with an unquoted backslash is a <application>psql</application> + meta-command that is processed by <application>psql</application> + itself. These commands make + <application>psql</application> more useful for administration or + scripting. Meta-commands are often called slash or backslash commands. + </para> + + <para> + The format of a <application>psql</application> command is the backslash, + followed immediately by a command verb, then any arguments. The arguments + are separated from the command verb and each other by any number of + whitespace characters. + </para> + + <para> + To include whitespace in an argument you can quote it with + single quotes. To include a single quote in an argument, + write two single quotes within single-quoted text. + Anything contained in single quotes is + furthermore subject to C-like substitutions for + <literal>\n</literal> (new line), <literal>\t</literal> (tab), + <literal>\b</literal> (backspace), <literal>\r</literal> (carriage return), + <literal>\f</literal> (form feed), + <literal>\</literal><replaceable>digits</replaceable> (octal), and + <literal>\x</literal><replaceable>digits</replaceable> (hexadecimal). + A backslash preceding any other character within single-quoted text + quotes that single character, whatever it is. + </para> + + <para> + If an unquoted colon (<literal>:</literal>) followed by a + <application>psql</application> variable name appears within an argument, it is + replaced by the variable's value, as described in <xref + linkend="app-psql-interpolation"/> below. + The forms <literal>:'<replaceable>variable_name</replaceable>'</literal> and + <literal>:"<replaceable>variable_name</replaceable>"</literal> described there + work as well. + The <literal>:{?<replaceable>variable_name</replaceable>}</literal> syntax allows + testing whether a variable is defined. It is substituted by + TRUE or FALSE. + Escaping the colon with a backslash protects it from substitution. + </para> + + <para> + Within an argument, text that is enclosed in backquotes + (<literal>`</literal>) is taken as a command line that is passed to the + shell. The output of the command (with any trailing newline removed) + replaces the backquoted text. Within the text enclosed in backquotes, + no special quoting or other processing occurs, except that appearances + of <literal>:<replaceable>variable_name</replaceable></literal> where + <replaceable>variable_name</replaceable> is a <application>psql</application> variable name + are replaced by the variable's value. Also, appearances of + <literal>:'<replaceable>variable_name</replaceable>'</literal> are replaced by the + variable's value suitably quoted to become a single shell command + argument. (The latter form is almost always preferable, unless you are + very sure of what is in the variable.) Because carriage return and line + feed characters cannot be safely quoted on all platforms, the + <literal>:'<replaceable>variable_name</replaceable>'</literal> form prints an + error message and does not substitute the variable value when such + characters appear in the value. + </para> + + <para> + Some commands take an <acronym>SQL</acronym> identifier (such as a + table name) as argument. These arguments follow the syntax rules + of <acronym>SQL</acronym>: Unquoted letters are forced to + lowercase, while double quotes (<literal>"</literal>) protect letters + from case conversion and allow incorporation of whitespace into + the identifier. Within double quotes, paired double quotes reduce + to a single double quote in the resulting name. For example, + <literal>FOO"BAR"BAZ</literal> is interpreted as <literal>fooBARbaz</literal>, + and <literal>"A weird"" name"</literal> becomes <literal>A weird" + name</literal>. + </para> + + <para> + Parsing for arguments stops at the end of the line, or when another + unquoted backslash is found. An unquoted backslash + is taken as the beginning of a new meta-command. The special + sequence <literal>\\</literal> (two backslashes) marks the end of + arguments and continues parsing <acronym>SQL</acronym> commands, if + any. That way <acronym>SQL</acronym> and + <application>psql</application> commands can be freely mixed on a + line. But in any case, the arguments of a meta-command cannot + continue beyond the end of the line. + </para> + + <para> + Many of the meta-commands act on the <firstterm>current query buffer</firstterm>. + This is simply a buffer holding whatever SQL command text has been typed + but not yet sent to the server for execution. This will include previous + input lines as well as any text appearing before the meta-command on the + same line. + </para> + + <para> + The following meta-commands are defined: + + <variablelist> + <varlistentry> + <term><literal>\a</literal></term> + <listitem> + <para> + If the current table output format is unaligned, it is switched to aligned. + If it is not unaligned, it is set to unaligned. This command is + kept for backwards compatibility. See <command>\pset</command> for a + more general solution. + </para> + </listitem> + </varlistentry> + + <varlistentry> + <term><literal>\c</literal> or <literal>\connect [ -reuse-previous=<replaceable class="parameter">on|off</replaceable> ] [ <replaceable class="parameter">dbname</replaceable> [ <replaceable class="parameter">username</replaceable> ] [ <replaceable class="parameter">host</replaceable> ] [ <replaceable class="parameter">port</replaceable> ] | <replaceable class="parameter">conninfo</replaceable> ]</literal></term> + <listitem> + <para> + Establishes a new connection to a <productname>PostgreSQL</productname> + server. The connection parameters to use can be specified either + using a positional syntax (one or more of database name, user, + host, and port), or using a <replaceable>conninfo</replaceable> + connection string as detailed in + <xref linkend="libpq-connstring"/>. If no arguments are given, a + new connection is made using the same parameters as before. + </para> + + <para> + Specifying any + of <replaceable class="parameter">dbname</replaceable>, + <replaceable class="parameter">username</replaceable>, + <replaceable class="parameter">host</replaceable> or + <replaceable class="parameter">port</replaceable> + as <literal>-</literal> is equivalent to omitting that parameter. + </para> + + <para> + The new connection can re-use connection parameters from the previous + connection; not only database name, user, host, and port, but other + settings such as <replaceable>sslmode</replaceable>. By default, + parameters are re-used in the positional syntax, but not when + a <replaceable>conninfo</replaceable> string is given. Passing a + first argument of <literal>-reuse-previous=on</literal> + or <literal>-reuse-previous=off</literal> overrides that default. If + parameters are re-used, then any parameter not explicitly specified as + a positional parameter or in the <replaceable>conninfo</replaceable> + string is taken from the existing connection's parameters. An + exception is that if the <replaceable>host</replaceable> setting + is changed from its previous value using the positional syntax, + any <replaceable>hostaddr</replaceable> setting present in the + existing connection's parameters is dropped. + Also, any password used for the existing connection will be re-used + only if the user, host, and port settings are not changed. + When the command neither specifies nor reuses a particular parameter, + the <application>libpq</application> default is used. + </para> + + <para> + If the new connection is successfully made, the previous + connection is closed. + If the connection attempt fails (wrong user name, access + denied, etc.), the previous connection will be kept if + <application>psql</application> is in interactive mode. But when + executing a non-interactive script, the old connection is closed + and an error is reported. That may or may not terminate the + script; if it does not, all database-accessing commands will fail + until another <literal>\connect</literal> command is successfully + executed. This distinction was chosen as + a user convenience against typos on the one hand, and a safety + mechanism that scripts are not accidentally acting on the + wrong database on the other hand. + Note that whenever a <literal>\connect</literal> command attempts + to re-use parameters, the values re-used are those of the last + successful connection, not of any failed attempts made subsequently. + However, in the case of a + non-interactive <literal>\connect</literal> failure, no parameters + are allowed to be re-used later, since the script would likely be + expecting the values from the failed <literal>\connect</literal> + to be re-used. + </para> + + <para> + Examples: + </para> +<programlisting> +=> \c mydb myuser host.dom 6432 +=> \c service=foo +=> \c "host=localhost port=5432 dbname=mydb connect_timeout=10 sslmode=disable" +=> \c -reuse-previous=on sslmode=require -- changes only sslmode +=> \c postgresql://tom@localhost/mydb?application_name=myapp +</programlisting> + </listitem> + </varlistentry> + + <varlistentry> + <term><literal>\C [ <replaceable class="parameter">title</replaceable> ]</literal></term> + <listitem> + <para> + Sets the title of any tables being printed as the result of a + query or unset any such title. This command is equivalent to + <literal>\pset title <replaceable + class="parameter">title</replaceable></literal>. (The name of + this command derives from <quote>caption</quote>, as it was + previously only used to set the caption in an + <acronym>HTML</acronym> table.) + </para> + </listitem> + </varlistentry> + + <varlistentry> + <term><literal>\cd [ <replaceable>directory</replaceable> ]</literal></term> + <listitem> + <para> + Changes the current working directory to + <replaceable>directory</replaceable>. Without argument, changes + to the current user's home directory. + </para> + + <tip> + <para> + To print your current working directory, use <literal>\! pwd</literal>. + </para> + </tip> + </listitem> + </varlistentry> + + <varlistentry> + <term><literal>\conninfo</literal></term> + <listitem> + <para> + Outputs information about the current database connection. + </para> + </listitem> + </varlistentry> + + <varlistentry id="app-psql-meta-commands-copy"> + <term><literal>\copy { <replaceable class="parameter">table</replaceable> [ ( <replaceable class="parameter">column_list</replaceable> ) ] } + <literal>from</literal> + { <replaceable class="parameter">'filename'</replaceable> | program <replaceable class="parameter">'command'</replaceable> | stdin | pstdin } + [ [ with ] ( <replaceable class="parameter">option</replaceable> [, ...] ) ] + [ where <replaceable class="parameter">condition</replaceable> ]</literal></term> + + <term><literal>\copy { <replaceable class="parameter">table</replaceable> [ ( <replaceable class="parameter">column_list</replaceable> ) ] | ( <replaceable class="parameter">query</replaceable> ) } + <literal>to</literal> + { <replaceable class="parameter">'filename'</replaceable> | program <replaceable class="parameter">'command'</replaceable> | stdout | pstdout } + [ [ with ] ( <replaceable class="parameter">option</replaceable> [, ...] ) ]</literal></term> + + <listitem> + <para> + Performs a frontend (client) copy. This is an operation that + runs an <acronym>SQL</acronym> <link linkend="sql-copy"><command>COPY</command></link> + command, but instead of the server + reading or writing the specified file, + <application>psql</application> reads or writes the file and + routes the data between the server and the local file system. + This means that file accessibility and privileges are those of + the local user, not the server, and no SQL superuser + privileges are required. + </para> + + <para> + When <literal>program</literal> is specified, + <replaceable class="parameter">command</replaceable> is + executed by <application>psql</application> and the data passed from + or to <replaceable class="parameter">command</replaceable> is + routed between the server and the client. + Again, the execution privileges are those of + the local user, not the server, and no SQL superuser + privileges are required. + </para> + + <para> + For <literal>\copy ... from stdin</literal>, data rows are read from the same + source that issued the command, continuing until <literal>\.</literal> + is read or the stream reaches <acronym>EOF</acronym>. This option is useful + for populating tables in-line within an SQL script file. + For <literal>\copy ... to stdout</literal>, output is sent to the same place + as <application>psql</application> command output, and + the <literal>COPY <replaceable>count</replaceable></literal> command status is + not printed (since it might be confused with a data row). + To read/write <application>psql</application>'s standard input or + output regardless of the current command source or <literal>\o</literal> + option, write <literal>from pstdin</literal> or <literal>to pstdout</literal>. + </para> + + <para> + The syntax of this command is similar to that of the + <acronym>SQL</acronym> <link linkend="sql-copy"><command>COPY</command></link> + command. All options other than the data source/destination are + as specified for <command>COPY</command>. + Because of this, special parsing rules apply to the <command>\copy</command> + meta-command. Unlike most other meta-commands, the entire remainder + of the line is always taken to be the arguments of <command>\copy</command>, + and neither variable interpolation nor backquote expansion are + performed in the arguments. + </para> + + <tip> + <para> + Another way to obtain the same result as <literal>\copy + ... to</literal> is to use the <acronym>SQL</acronym> <literal>COPY + ... TO STDOUT</literal> command and terminate it + with <literal>\g <replaceable>filename</replaceable></literal> + or <literal>\g |<replaceable>program</replaceable></literal>. + Unlike <literal>\copy</literal>, this method allows the command to + span multiple lines; also, variable interpolation and backquote + expansion can be used. + </para> + </tip> + + <tip> + <para> + These operations are not as efficient as the <acronym>SQL</acronym> + <command>COPY</command> command with a file or program data source or + destination, because all data must pass through the client/server + connection. For large amounts of data the <acronym>SQL</acronym> + command might be preferable. + Also, because of this pass-through method, <literal>\copy + ... from</literal> in <acronym>CSV</acronym> mode will erroneously + treat a <literal>\.</literal> data value alone on a line as an + end-of-input marker. + </para> + </tip> + + </listitem> + </varlistentry> + + <varlistentry> + <term><literal>\copyright</literal></term> + <listitem> + <para> + Shows the copyright and distribution terms of + <productname>PostgreSQL</productname>. + </para> + </listitem> + </varlistentry> + + + <varlistentry id="app-psql-meta-commands-crosstabview"> + <term><literal>\crosstabview [ + <replaceable class="parameter">colV</replaceable> + [ <replaceable class="parameter">colH</replaceable> + [ <replaceable class="parameter">colD</replaceable> + [ <replaceable class="parameter">sortcolH</replaceable> + ] ] ] ] </literal></term> + <listitem> + <para> + Executes the current query buffer (like <literal>\g</literal>) and + shows the results in a crosstab grid. + The query must return at least three columns. + The output column identified by <replaceable class="parameter">colV</replaceable> + becomes a vertical header and the output column identified by + <replaceable class="parameter">colH</replaceable> + becomes a horizontal header. + <replaceable class="parameter">colD</replaceable> identifies + the output column to display within the grid. + <replaceable class="parameter">sortcolH</replaceable> identifies + an optional sort column for the horizontal header. + </para> + + <para> + Each column specification can be a column number (starting at 1) or + a column name. The usual SQL case folding and quoting rules apply to + column names. If omitted, + <replaceable class="parameter">colV</replaceable> is taken as column 1 + and <replaceable class="parameter">colH</replaceable> as column 2. + <replaceable class="parameter">colH</replaceable> must differ from + <replaceable class="parameter">colV</replaceable>. + If <replaceable class="parameter">colD</replaceable> is not + specified, then there must be exactly three columns in the query + result, and the column that is neither + <replaceable class="parameter">colV</replaceable> nor + <replaceable class="parameter">colH</replaceable> + is taken to be <replaceable class="parameter">colD</replaceable>. + </para> + + <para> + The vertical header, displayed as the leftmost column, contains the + values found in column <replaceable class="parameter">colV</replaceable>, in the + same order as in the query results, but with duplicates removed. + </para> + + <para> + The horizontal header, displayed as the first row, contains the values + found in column <replaceable class="parameter">colH</replaceable>, + with duplicates removed. By default, these appear in the same order + as in the query results. But if the + optional <replaceable class="parameter">sortcolH</replaceable> argument is given, + it identifies a column whose values must be integer numbers, and the + values from <replaceable class="parameter">colH</replaceable> will + appear in the horizontal header sorted according to the + corresponding <replaceable class="parameter">sortcolH</replaceable> values. + </para> + + <para> + Inside the crosstab grid, for each distinct value <literal>x</literal> + of <replaceable class="parameter">colH</replaceable> and each distinct + value <literal>y</literal> + of <replaceable class="parameter">colV</replaceable>, the cell located + at the intersection <literal>(x,y)</literal> contains the value of + the <literal>colD</literal> column in the query result row for which + the value of <replaceable class="parameter">colH</replaceable> + is <literal>x</literal> and the value + of <replaceable class="parameter">colV</replaceable> + is <literal>y</literal>. If there is no such row, the cell is empty. If + there are multiple such rows, an error is reported. + </para> + </listitem> + </varlistentry> + + + <varlistentry> + <term><literal>\d[S+] [ <link linkend="app-psql-patterns"><replaceable class="parameter">pattern</replaceable></link> ]</literal></term> + + <listitem> + <para> + For each relation (table, view, materialized view, index, sequence, + or foreign table) + or composite type matching the + <replaceable class="parameter">pattern</replaceable>, show all + columns, their types, the tablespace (if not the default) and any + special attributes such as <literal>NOT NULL</literal> or defaults. + Associated indexes, constraints, rules, and triggers are + also shown. For foreign tables, the associated foreign + server is shown as well. + (<quote>Matching the pattern</quote> is defined in + <xref linkend="app-psql-patterns"/> below.) + </para> + + <para> + For some types of relation, <literal>\d</literal> shows additional information + for each column: column values for sequences, indexed expressions for + indexes, and foreign data wrapper options for foreign tables. + </para> + + <para> + The command form <literal>\d+</literal> is identical, except that + more information is displayed: any comments associated with the + columns of the table are shown, as is the presence of OIDs in the + table, the view definition if the relation is a view, a non-default + <link linkend="sql-altertable-replica-identity">replica + identity</link> setting and the + <link linkend="sql-create-access-method">access method</link> name + if the relation has an access method. + </para> + + <para> + By default, only user-created objects are shown; supply a + pattern or the <literal>S</literal> modifier to include system + objects. + </para> + + <note> + <para> + If <command>\d</command> is used without a + <replaceable class="parameter">pattern</replaceable> argument, it is + equivalent to <command>\dtvmsE</command> which will show a list of + all visible tables, views, materialized views, sequences and + foreign tables. + This is purely a convenience measure. + </para> + </note> + </listitem> + </varlistentry> + + <varlistentry> + <term><literal>\da[S] [ <link linkend="app-psql-patterns"><replaceable class="parameter">pattern</replaceable></link> ]</literal></term> + + <listitem> + <para> + Lists aggregate functions, together with their + return type and the data types they operate on. If <replaceable + class="parameter">pattern</replaceable> + is specified, only aggregates whose names match the pattern are shown. + By default, only user-created objects are shown; supply a + pattern or the <literal>S</literal> modifier to include system + objects. + </para> + </listitem> + </varlistentry> + + <varlistentry> + <term><literal>\dA[+] [ <link linkend="app-psql-patterns"><replaceable class="parameter">pattern</replaceable></link> ]</literal></term> + + <listitem> + <para> + Lists access methods. If <replaceable + class="parameter">pattern</replaceable> is specified, only access + methods whose names match the pattern are shown. If + <literal>+</literal> is appended to the command name, each access + method is listed with its associated handler function and description. + </para> + </listitem> + </varlistentry> + + <varlistentry> + <term> + <literal>\dAc[+] + [<link linkend="app-psql-patterns"><replaceable class="parameter">access-method-pattern</replaceable></link> + [<link linkend="app-psql-patterns"><replaceable class="parameter">input-type-pattern</replaceable></link>]] + </literal> + </term> + <listitem> + <para> + Lists operator classes + (see <xref linkend="xindex-opclass"/>). + If <replaceable class="parameter">access-method-pattern</replaceable> + is specified, only operator classes associated with access methods whose + names match that pattern are listed. + If <replaceable class="parameter">input-type-pattern</replaceable> + is specified, only operator classes associated with input types whose + names match that pattern are listed. + If <literal>+</literal> is appended to the command name, each operator + class is listed with its associated operator family and owner. + </para> + </listitem> + </varlistentry> + + <varlistentry> + <term> + <literal>\dAf[+] + [<link linkend="app-psql-patterns"><replaceable class="parameter">access-method-pattern</replaceable></link> + [<link linkend="app-psql-patterns"><replaceable class="parameter">input-type-pattern</replaceable></link>]] + </literal> + </term> + <listitem> + <para> + Lists operator families + (see <xref linkend="xindex-opfamily"/>). + If <replaceable class="parameter">access-method-pattern</replaceable> + is specified, only operator families associated with access methods whose + names match that pattern are listed. + If <replaceable class="parameter">input-type-pattern</replaceable> + is specified, only operator families associated with input types whose + names match that pattern are listed. + If <literal>+</literal> is appended to the command name, each operator + family is listed with its owner. + </para> + </listitem> + </varlistentry> + + <varlistentry> + <term> + <literal>\dAo[+] + [<link linkend="app-psql-patterns"><replaceable class="parameter">access-method-pattern</replaceable></link> + [<link linkend="app-psql-patterns"><replaceable class="parameter">operator-family-pattern</replaceable></link>]] + </literal> + </term> + + <listitem> + <para> + Lists operators associated with operator families + (see <xref linkend="xindex-strategies"/>). + If <replaceable class="parameter">access-method-pattern</replaceable> + is specified, only members of operator families associated with access + methods whose names match that pattern are listed. + If <replaceable class="parameter">operator-family-pattern</replaceable> + is specified, only members of operator families whose names match that + pattern are listed. + If <literal>+</literal> is appended to the command name, each operator + is listed with its sort operator family (if it is an ordering operator). + </para> + </listitem> + </varlistentry> + + <varlistentry> + <term> + <literal>\dAp[+] + [<link linkend="app-psql-patterns"><replaceable class="parameter">access-method-pattern</replaceable></link> + [<link linkend="app-psql-patterns"><replaceable class="parameter">operator-family-pattern</replaceable></link>]] + </literal> + </term> + <listitem> + <para> + Lists support functions associated with operator families + (see <xref linkend="xindex-support"/>). + If <replaceable class="parameter">access-method-pattern</replaceable> + is specified, only functions of operator families associated with + access methods whose names match that pattern are listed. + If <replaceable class="parameter">operator-family-pattern</replaceable> + is specified, only functions of operator families whose names match + that pattern are listed. + If <literal>+</literal> is appended to the command name, functions are + displayed verbosely, with their actual parameter lists. + </para> + </listitem> + </varlistentry> + + <varlistentry> + <term><literal>\db[+] [ <link linkend="app-psql-patterns"><replaceable class="parameter">pattern</replaceable></link> ]</literal></term> + + <listitem> + <para> + Lists tablespaces. If <replaceable + class="parameter">pattern</replaceable> + is specified, only tablespaces whose names match the pattern are shown. + If <literal>+</literal> is appended to the command name, each tablespace + is listed with its associated options, on-disk size, permissions and + description. + </para> + </listitem> + </varlistentry> + + + <varlistentry> + <term><literal>\dc[S+] [ <link linkend="app-psql-patterns"><replaceable class="parameter">pattern</replaceable></link> ]</literal></term> + <listitem> + <para> + Lists conversions between character-set encodings. + If <replaceable class="parameter">pattern</replaceable> + is specified, only conversions whose names match the pattern are + listed. + By default, only user-created objects are shown; supply a + pattern or the <literal>S</literal> modifier to include system + objects. + If <literal>+</literal> is appended to the command name, each object + is listed with its associated description. + </para> + </listitem> + </varlistentry> + + + <varlistentry> + <term><literal>\dconfig[+] [ <link linkend="app-psql-patterns"><replaceable class="parameter">pattern</replaceable></link> ]</literal></term> + <listitem> + <para> + Lists server configuration parameters and their values. + If <replaceable class="parameter">pattern</replaceable> is specified, + only parameters whose names match the pattern are listed. Without + a <replaceable class="parameter">pattern</replaceable>, only + parameters that are set to non-default values are listed. + (Use <literal>\dconfig *</literal> to see all parameters.) + If <literal>+</literal> is appended to the command name, each + parameter is listed with its data type, context in which the + parameter can be set, and access privileges (if non-default access + privileges have been granted). + </para> + </listitem> + </varlistentry> + + + <varlistentry> + <term><literal>\dC[+] [ <link linkend="app-psql-patterns"><replaceable class="parameter">pattern</replaceable></link> ]</literal></term> + <listitem> + <para> + Lists type casts. + If <replaceable class="parameter">pattern</replaceable> + is specified, only casts whose source or target types match the + pattern are listed. + If <literal>+</literal> is appended to the command name, each object + is listed with its associated description. + </para> + </listitem> + </varlistentry> + + + <varlistentry> + <term><literal>\dd[S] [ <link linkend="app-psql-patterns"><replaceable class="parameter">pattern</replaceable></link> ]</literal></term> + <listitem> + <para> + Shows the descriptions of objects of type <literal>constraint</literal>, + <literal>operator class</literal>, <literal>operator family</literal>, + <literal>rule</literal>, and <literal>trigger</literal>. All + other comments may be viewed by the respective backslash commands for + those object types. + </para> + + <para><literal>\dd</literal> displays descriptions for objects matching the + <replaceable class="parameter">pattern</replaceable>, or of visible + objects of the appropriate type if no argument is given. But in either + case, only objects that have a description are listed. + By default, only user-created objects are shown; supply a + pattern or the <literal>S</literal> modifier to include system + objects. + </para> + + <para> + Descriptions for objects can be created with the <link + linkend="sql-comment"><command>COMMENT</command></link> + <acronym>SQL</acronym> command. + </para> + </listitem> + </varlistentry> + + + <varlistentry> + <term><literal>\dD[S+] [ <link linkend="app-psql-patterns"><replaceable class="parameter">pattern</replaceable></link> ]</literal></term> + <listitem> + <para> + Lists domains. If <replaceable + class="parameter">pattern</replaceable> + is specified, only domains whose names match the pattern are shown. + By default, only user-created objects are shown; supply a + pattern or the <literal>S</literal> modifier to include system + objects. + If <literal>+</literal> is appended to the command name, each object + is listed with its associated permissions and description. + </para> + </listitem> + </varlistentry> + + + <varlistentry> + <term><literal>\ddp [ <link linkend="app-psql-patterns"><replaceable class="parameter">pattern</replaceable></link> ]</literal></term> + <listitem> + <para> + Lists default access privilege settings. An entry is shown for + each role (and schema, if applicable) for which the default + privilege settings have been changed from the built-in defaults. + If <replaceable class="parameter">pattern</replaceable> is + specified, only entries whose role name or schema name matches + the pattern are listed. + </para> + + <para> + The <link linkend="sql-alterdefaultprivileges"><command>ALTER DEFAULT + PRIVILEGES</command></link> command is used to set default access + privileges. The meaning of the privilege display is explained in + <xref linkend="ddl-priv"/>. + </para> + </listitem> + </varlistentry> + + + <varlistentry> + <term><literal>\dE[S+] [ <link linkend="app-psql-patterns"><replaceable class="parameter">pattern</replaceable></link> ]</literal></term> + <term><literal>\di[S+] [ <link linkend="app-psql-patterns"><replaceable class="parameter">pattern</replaceable></link> ]</literal></term> + <term><literal>\dm[S+] [ <link linkend="app-psql-patterns"><replaceable class="parameter">pattern</replaceable></link> ]</literal></term> + <term><literal>\ds[S+] [ <link linkend="app-psql-patterns"><replaceable class="parameter">pattern</replaceable></link> ]</literal></term> + <term><literal>\dt[S+] [ <link linkend="app-psql-patterns"><replaceable class="parameter">pattern</replaceable></link> ]</literal></term> + <term><literal>\dv[S+] [ <link linkend="app-psql-patterns"><replaceable class="parameter">pattern</replaceable></link> ]</literal></term> + + <listitem> + <para> + In this group of commands, the letters <literal>E</literal>, + <literal>i</literal>, <literal>m</literal>, <literal>s</literal>, + <literal>t</literal>, and <literal>v</literal> + stand for foreign table, index, materialized view, + sequence, table, and view, + respectively. + You can specify any or all of + these letters, in any order, to obtain a listing of objects + of these types. For example, <literal>\dti</literal> lists + tables and indexes. If <literal>+</literal> is + appended to the command name, each object is listed with its + persistence status (permanent, temporary, or unlogged), + physical size on disk, and associated description if any. + If <replaceable class="parameter">pattern</replaceable> is + specified, only objects whose names match the pattern are listed. + By default, only user-created objects are shown; supply a + pattern or the <literal>S</literal> modifier to include system + objects. + </para> + </listitem> + </varlistentry> + + + <varlistentry> + <term><literal>\des[+] [ <link linkend="app-psql-patterns"><replaceable class="parameter">pattern</replaceable></link> ]</literal></term> + <listitem> + <para> + Lists foreign servers (mnemonic: <quote>external + servers</quote>). + If <replaceable class="parameter">pattern</replaceable> is + specified, only those servers whose name matches the pattern + are listed. If the form <literal>\des+</literal> is used, a + full description of each server is shown, including the + server's access privileges, type, version, options, and description. + </para> + </listitem> + </varlistentry> + + + <varlistentry> + <term><literal>\det[+] [ <link linkend="app-psql-patterns"><replaceable class="parameter">pattern</replaceable></link> ]</literal></term> + <listitem> + <para> + Lists foreign tables (mnemonic: <quote>external tables</quote>). + If <replaceable class="parameter">pattern</replaceable> is + specified, only entries whose table name or schema name matches + the pattern are listed. If the form <literal>\det+</literal> + is used, generic options and the foreign table description + are also displayed. + </para> + </listitem> + </varlistentry> + + + <varlistentry> + <term><literal>\deu[+] [ <link linkend="app-psql-patterns"><replaceable class="parameter">pattern</replaceable></link> ]</literal></term> + <listitem> + <para> + Lists user mappings (mnemonic: <quote>external + users</quote>). + If <replaceable class="parameter">pattern</replaceable> is + specified, only those mappings whose user names match the + pattern are listed. If the form <literal>\deu+</literal> is + used, additional information about each mapping is shown. + </para> + + <caution> + <para> + <literal>\deu+</literal> might also display the user name and + password of the remote user, so care should be taken not to + disclose them. + </para> + </caution> + </listitem> + </varlistentry> + + + <varlistentry> + <term><literal>\dew[+] [ <link linkend="app-psql-patterns"><replaceable class="parameter">pattern</replaceable></link> ]</literal></term> + <listitem> + <para> + Lists foreign-data wrappers (mnemonic: <quote>external + wrappers</quote>). + If <replaceable class="parameter">pattern</replaceable> is + specified, only those foreign-data wrappers whose name matches + the pattern are listed. If the form <literal>\dew+</literal> + is used, the access privileges, options, and description of the + foreign-data wrapper are also shown. + </para> + </listitem> + </varlistentry> + + + <varlistentry> + <term><literal>\df[anptwS+] [ <link linkend="app-psql-patterns"><replaceable class="parameter">pattern</replaceable></link> [ <replaceable class="parameter">arg_pattern</replaceable> ... ] ]</literal></term> + + <listitem> + <para> + Lists functions, together with their result data types, argument data + types, and function types, which are classified as <quote>agg</quote> + (aggregate), <quote>normal</quote>, <quote>procedure</quote>, <quote>trigger</quote>, or <quote>window</quote>. + To display only functions + of specific type(s), add the corresponding letters <literal>a</literal>, + <literal>n</literal>, <literal>p</literal>, <literal>t</literal>, or <literal>w</literal> to the command. + If <replaceable + class="parameter">pattern</replaceable> is specified, only + functions whose names match the pattern are shown. + Any additional arguments are type-name patterns, which are matched + to the type names of the first, second, and so on arguments of the + function. (Matching functions can have more arguments than what + you specify. To prevent that, write a dash <literal>-</literal> as + the last <replaceable class="parameter">arg_pattern</replaceable>.) + By default, only user-created + objects are shown; supply a pattern or the <literal>S</literal> + modifier to include system objects. + If the form <literal>\df+</literal> is used, additional information + about each function is shown, including volatility, + parallel safety, owner, security classification, access privileges, + language, source code and description. + </para> + + </listitem> + </varlistentry> + + <varlistentry> + <term><literal>\dF[+] [ <link linkend="app-psql-patterns"><replaceable class="parameter">pattern</replaceable></link> ]</literal></term> + <listitem> + <para> + Lists text search configurations. + If <replaceable class="parameter">pattern</replaceable> is specified, + only configurations whose names match the pattern are shown. + If the form <literal>\dF+</literal> is used, a full description of + each configuration is shown, including the underlying text search + parser and the dictionary list for each parser token type. + </para> + </listitem> + </varlistentry> + + <varlistentry> + <term><literal>\dFd[+] [ <link linkend="app-psql-patterns"><replaceable class="parameter">pattern</replaceable></link> ]</literal></term> + <listitem> + <para> + Lists text search dictionaries. + If <replaceable class="parameter">pattern</replaceable> is specified, + only dictionaries whose names match the pattern are shown. + If the form <literal>\dFd+</literal> is used, additional information + is shown about each selected dictionary, including the underlying + text search template and the option values. + </para> + </listitem> + </varlistentry> + + <varlistentry> + <term><literal>\dFp[+] [ <link linkend="app-psql-patterns"><replaceable class="parameter">pattern</replaceable></link> ]</literal></term> + <listitem> + <para> + Lists text search parsers. + If <replaceable class="parameter">pattern</replaceable> is specified, + only parsers whose names match the pattern are shown. + If the form <literal>\dFp+</literal> is used, a full description of + each parser is shown, including the underlying functions and the + list of recognized token types. + </para> + </listitem> + </varlistentry> + + <varlistentry> + <term><literal>\dFt[+] [ <link linkend="app-psql-patterns"><replaceable class="parameter">pattern</replaceable></link> ]</literal></term> + <listitem> + <para> + Lists text search templates. + If <replaceable class="parameter">pattern</replaceable> is specified, + only templates whose names match the pattern are shown. + If the form <literal>\dFt+</literal> is used, additional information + is shown about each template, including the underlying function names. + </para> + </listitem> + </varlistentry> + + + <varlistentry> + <term><literal>\dg[S+] [ <link linkend="app-psql-patterns"><replaceable class="parameter">pattern</replaceable></link> ]</literal></term> + <listitem> + <para> + Lists database roles. + (Since the concepts of <quote>users</quote> and <quote>groups</quote> have been + unified into <quote>roles</quote>, this command is now equivalent to + <literal>\du</literal>.) + By default, only user-created roles are shown; supply the + <literal>S</literal> modifier to include system roles. + If <replaceable class="parameter">pattern</replaceable> is specified, + only those roles whose names match the pattern are listed. + If the form <literal>\dg+</literal> is used, additional information + is shown about each role; currently this adds the comment for each + role. + </para> + </listitem> + </varlistentry> + + + <varlistentry> + <term><literal>\dl[+]</literal></term> + <listitem> + <para> + This is an alias for <command>\lo_list</command>, which shows a + list of large objects. + If <literal>+</literal> is appended to the command name, + each large object is listed with its associated permissions, + if any. + </para> + </listitem> + </varlistentry> + + <varlistentry> + <term><literal>\dL[S+] [ <link linkend="app-psql-patterns"><replaceable class="parameter">pattern</replaceable></link> ]</literal></term> + <listitem> + <para> + Lists procedural languages. If <replaceable + class="parameter">pattern</replaceable> + is specified, only languages whose names match the pattern are listed. + By default, only user-created languages + are shown; supply the <literal>S</literal> modifier to include system + objects. If <literal>+</literal> is appended to the command name, each + language is listed with its call handler, validator, access privileges, + and whether it is a system object. + </para> + </listitem> + </varlistentry> + + + <varlistentry> + <term><literal>\dn[S+] [ <link linkend="app-psql-patterns"><replaceable class="parameter">pattern</replaceable></link> ]</literal></term> + + <listitem> + <para> + Lists schemas (namespaces). If <replaceable + class="parameter">pattern</replaceable> + is specified, only schemas whose names match the pattern are listed. + By default, only user-created objects are shown; supply a + pattern or the <literal>S</literal> modifier to include system objects. + If <literal>+</literal> is appended to the command name, each object + is listed with its associated permissions and description, if any. + </para> + </listitem> + </varlistentry> + + + <varlistentry> + <term><literal>\do[S+] [ <link linkend="app-psql-patterns"><replaceable class="parameter">pattern</replaceable></link> [ <replaceable class="parameter">arg_pattern</replaceable> [ <replaceable class="parameter">arg_pattern</replaceable> ] ] ]</literal></term> + <listitem> + <para> + Lists operators with their operand and result types. + If <replaceable class="parameter">pattern</replaceable> is + specified, only operators whose names match the pattern are listed. + If one <replaceable class="parameter">arg_pattern</replaceable> is + specified, only prefix operators whose right argument's type name + matches that pattern are listed. + If two <replaceable class="parameter">arg_pattern</replaceable>s + are specified, only binary operators whose argument type names match + those patterns are listed. (Alternatively, write <literal>-</literal> + for the unused argument of a unary operator.) + By default, only user-created objects are shown; supply a + pattern or the <literal>S</literal> modifier to include system + objects. + If <literal>+</literal> is appended to the command name, + additional information about each operator is shown, currently just + the name of the underlying function. + </para> + </listitem> + </varlistentry> + + + <varlistentry> + <term><literal>\dO[S+] [ <link linkend="app-psql-patterns"><replaceable class="parameter">pattern</replaceable></link> ]</literal></term> + <listitem> + <para> + Lists collations. + If <replaceable class="parameter">pattern</replaceable> is + specified, only collations whose names match the pattern are + listed. By default, only user-created objects are shown; + supply a pattern or the <literal>S</literal> modifier to + include system objects. If <literal>+</literal> is appended + to the command name, each collation is listed with its associated + description, if any. + Note that only collations usable with the current database's encoding + are shown, so the results may vary in different databases of the + same installation. + </para> + </listitem> + </varlistentry> + + + <varlistentry> + <term><literal>\dp [ <link linkend="app-psql-patterns"><replaceable class="parameter">pattern</replaceable></link> ]</literal></term> + <listitem> + <para> + Lists tables, views and sequences with their + associated access privileges. + If <replaceable class="parameter">pattern</replaceable> is + specified, only tables, views and sequences whose names match the + pattern are listed. + </para> + + <para> + The <link linkend="sql-grant"><command>GRANT</command></link> and + <link linkend="sql-revoke"><command>REVOKE</command></link> + commands are used to set access privileges. The meaning of the + privilege display is explained in + <xref linkend="ddl-priv"/>. + </para> + </listitem> + </varlistentry> + + + <varlistentry> + <term><literal>\dP[itn+] [ <link linkend="app-psql-patterns"><replaceable class="parameter">pattern</replaceable></link> ]</literal></term> + <listitem> + <para> + Lists partitioned relations. + If <replaceable class="parameter">pattern</replaceable> + is specified, only entries whose name matches the pattern are listed. + The modifiers <literal>t</literal> (tables) and <literal>i</literal> + (indexes) can be appended to the command, filtering the kind of + relations to list. By default, partitioned tables and indexes are + listed. + </para> + + <para> + If the modifier <literal>n</literal> (<quote>nested</quote>) is used, + or a pattern is specified, then non-root partitioned relations are + included, and a column is shown displaying the parent of each + partitioned relation. + </para> + + <para> + If <literal>+</literal> is appended to the command name, the sum of the + sizes of each relation's partitions is also displayed, along with the + relation's description. + If <literal>n</literal> is combined with <literal>+</literal>, two + sizes are shown: one including the total size of directly-attached + leaf partitions, and another showing the total size of all partitions, + including indirectly attached sub-partitions. + </para> + </listitem> + </varlistentry> + + <varlistentry> + <term><literal>\drds [ <link linkend="app-psql-patterns"><replaceable class="parameter">role-pattern</replaceable></link> [ <link linkend="app-psql-patterns"><replaceable class="parameter">database-pattern</replaceable></link> ] ]</literal></term> + <listitem> + <para> + Lists defined configuration settings. These settings can be + role-specific, database-specific, or both. + <replaceable>role-pattern</replaceable> and + <replaceable>database-pattern</replaceable> are used to select + specific roles and databases to list, respectively. If omitted, or if + <literal>*</literal> is specified, all settings are listed, including those + not role-specific or database-specific, respectively. + </para> + + <para> + The <link linkend="sql-alterrole"><command>ALTER ROLE</command></link> and + <link linkend="sql-alterdatabase"><command>ALTER DATABASE</command></link> + commands are used to define per-role and per-database configuration + settings. + </para> + </listitem> + </varlistentry> + + <varlistentry> + <term><literal>\dRp[+] [ <link linkend="app-psql-patterns"><replaceable class="parameter">pattern</replaceable></link> ]</literal></term> + <listitem> + <para> + Lists replication publications. + If <replaceable class="parameter">pattern</replaceable> is + specified, only those publications whose names match the pattern are + listed. + If <literal>+</literal> is appended to the command name, the tables and + schemas associated with each publication are shown as well. + </para> + </listitem> + </varlistentry> + + <varlistentry> + <term><literal>\dRs[+] [ <link linkend="app-psql-patterns"><replaceable class="parameter">pattern</replaceable></link> ]</literal></term> + <listitem> + <para> + Lists replication subscriptions. + If <replaceable class="parameter">pattern</replaceable> is + specified, only those subscriptions whose names match the pattern are + listed. + If <literal>+</literal> is appended to the command name, additional + properties of the subscriptions are shown. + </para> + </listitem> + </varlistentry> + + <varlistentry> + <term><literal>\dT[S+] [ <link linkend="app-psql-patterns"><replaceable class="parameter">pattern</replaceable></link> ]</literal></term> + <listitem> + <para> + Lists data types. + If <replaceable class="parameter">pattern</replaceable> is + specified, only types whose names match the pattern are listed. + If <literal>+</literal> is appended to the command name, each type is + listed with its internal name and size, its allowed values + if it is an <type>enum</type> type, and its associated permissions. + By default, only user-created objects are shown; supply a + pattern or the <literal>S</literal> modifier to include system + objects. + </para> + </listitem> + </varlistentry> + + <varlistentry> + <term><literal>\du[S+] [ <link linkend="app-psql-patterns"><replaceable class="parameter">pattern</replaceable></link> ]</literal></term> + <listitem> + <para> + Lists database roles. + (Since the concepts of <quote>users</quote> and <quote>groups</quote> have been + unified into <quote>roles</quote>, this command is now equivalent to + <literal>\dg</literal>.) + By default, only user-created roles are shown; supply the + <literal>S</literal> modifier to include system roles. + If <replaceable class="parameter">pattern</replaceable> is specified, + only those roles whose names match the pattern are listed. + If the form <literal>\du+</literal> is used, additional information + is shown about each role; currently this adds the comment for each + role. + </para> + </listitem> + </varlistentry> + + <varlistentry> + <term><literal>\dx[+] [ <link linkend="app-psql-patterns"><replaceable class="parameter">pattern</replaceable></link> ]</literal></term> + <listitem> + <para> + Lists installed extensions. + If <replaceable class="parameter">pattern</replaceable> + is specified, only those extensions whose names match the pattern + are listed. + If the form <literal>\dx+</literal> is used, all the objects belonging + to each matching extension are listed. + </para> + </listitem> + </varlistentry> + + <varlistentry> + <term><literal>\dX [ <link linkend="app-psql-patterns"><replaceable class="parameter">pattern</replaceable></link> ]</literal></term> + <listitem> + <para> + Lists extended statistics. + If <replaceable class="parameter">pattern</replaceable> + is specified, only those extended statistics whose names match the + pattern are listed. + </para> + + <para> + The status of each kind of extended statistics is shown in a column + named after its statistic kind (e.g. Ndistinct). + <literal>defined</literal> means that it was requested when creating + the statistics, and NULL means it wasn't requested. + You can use <structname>pg_stats_ext</structname> if you'd like to + know whether <link linkend="sql-analyze"><command>ANALYZE</command></link> + was run and statistics are available to the planner. + </para> + </listitem> + </varlistentry> + + <varlistentry> + <term><literal>\dy[+] [ <link linkend="app-psql-patterns"><replaceable class="parameter">pattern</replaceable></link> ]</literal></term> + <listitem> + <para> + Lists event triggers. + If <replaceable class="parameter">pattern</replaceable> + is specified, only those event triggers whose names match the pattern + are listed. + If <literal>+</literal> is appended to the command name, each object + is listed with its associated description. + </para> + </listitem> + </varlistentry> + + <varlistentry> + <term><literal>\e</literal> or <literal>\edit</literal> <literal> <optional> <replaceable class="parameter">filename</replaceable> </optional> <optional> <replaceable class="parameter">line_number</replaceable> </optional> </literal></term> + + <listitem> + <para> + If <replaceable class="parameter">filename</replaceable> is + specified, the file is edited; after the editor exits, the file's + content is copied into the current query buffer. If no <replaceable + class="parameter">filename</replaceable> is given, the current query + buffer is copied to a temporary file which is then edited in the same + fashion. Or, if the current query buffer is empty, the most recently + executed query is copied to a temporary file and edited in the same + fashion. + </para> + + <para> + If you edit a file or the previous query, and you quit the editor without + modifying the file, the query buffer is cleared. + Otherwise, the new contents of the query buffer are re-parsed according to + the normal rules of <application>psql</application>, treating the + whole buffer as a single line. Any complete queries are immediately + executed; that is, if the query buffer contains or ends with a + semicolon, everything up to that point is executed and removed from + the query buffer. Whatever remains in the query buffer is + redisplayed. Type semicolon or <literal>\g</literal> to send it, + or <literal>\r</literal> to cancel it by clearing the query buffer. + </para> + + <para> + Treating the buffer as a single line primarily affects meta-commands: + whatever is in the buffer after a meta-command will be taken as + argument(s) to the meta-command, even if it spans multiple lines. + (Thus you cannot make meta-command-using scripts this way. + Use <command>\i</command> for that.) + </para> + + <para> + If a line number is specified, <application>psql</application> will + position the cursor on the specified line of the file or query buffer. + Note that if a single all-digits argument is given, + <application>psql</application> assumes it is a line number, + not a file name. + </para> + + <tip> + <para> + See <xref linkend="app-psql-environment"/>, below, for how to + configure and customize your editor. + </para> + </tip> + </listitem> + </varlistentry> + + <varlistentry> + <term><literal>\echo <replaceable class="parameter">text</replaceable> [ ... ]</literal></term> + <listitem> + <para> + Prints the evaluated arguments to standard output, separated by + spaces and followed by a newline. This can be useful to + intersperse information in the output of scripts. For example: +<programlisting> +=> <userinput>\echo `date`</userinput> +Tue Oct 26 21:40:57 CEST 1999 +</programlisting> + If the first argument is an unquoted <literal>-n</literal> the trailing + newline is not written (nor is the first argument). + </para> + + <tip> + <para> + If you use the <command>\o</command> command to redirect your + query output you might wish to use <command>\qecho</command> + instead of this command. See also <command>\warn</command>. + </para> + </tip> + </listitem> + </varlistentry> + + <varlistentry> + <term><literal>\ef <optional> <replaceable class="parameter">function_description</replaceable> <optional> <replaceable class="parameter">line_number</replaceable> </optional> </optional> </literal></term> + + <listitem> + <para> + This command fetches and edits the definition of the named function or procedure, + in the form of a <command>CREATE OR REPLACE FUNCTION</command> or + <command>CREATE OR REPLACE PROCEDURE</command> command. + Editing is done in the same way as for <literal>\edit</literal>. + If you quit the editor without saving, the statement is discarded. + If you save and exit the editor, the updated command is executed immediately + if you added a semicolon to it. Otherwise it is redisplayed; + type semicolon or <literal>\g</literal> to send it, or <literal>\r</literal> + to cancel. + </para> + + <para> + The target function can be specified by name alone, or by name + and arguments, for example <literal>foo(integer, text)</literal>. + The argument types must be given if there is more + than one function of the same name. + </para> + + <para> + If no function is specified, a blank <command>CREATE FUNCTION</command> + template is presented for editing. + </para> + + <para> + If a line number is specified, <application>psql</application> will + position the cursor on the specified line of the function body. + (Note that the function body typically does not begin on the first + line of the file.) + </para> + + <para> + Unlike most other meta-commands, the entire remainder of the line is + always taken to be the argument(s) of <command>\ef</command>, and neither + variable interpolation nor backquote expansion are performed in the + arguments. + </para> + + <tip> + <para> + See <xref linkend="app-psql-environment"/>, below, for how to + configure and customize your editor. + </para> + </tip> + </listitem> + </varlistentry> + + + <varlistentry> + <term><literal>\encoding [ <replaceable class="parameter">encoding</replaceable> ]</literal></term> + + <listitem> + <para> + Sets the client character set encoding. Without an argument, this command + shows the current encoding. + </para> + </listitem> + </varlistentry> + + + <varlistentry> + <term><literal>\errverbose</literal></term> + + <listitem> + <para> + Repeats the most recent server error message at maximum + verbosity, as though <varname>VERBOSITY</varname> were set + to <literal>verbose</literal> and <varname>SHOW_CONTEXT</varname> were + set to <literal>always</literal>. + </para> + </listitem> + </varlistentry> + + + <varlistentry> + <term><literal>\ev <optional> <replaceable class="parameter">view_name</replaceable> <optional> <replaceable class="parameter">line_number</replaceable> </optional> </optional> </literal></term> + + <listitem> + <para> + This command fetches and edits the definition of the named view, + in the form of a <command>CREATE OR REPLACE VIEW</command> command. + Editing is done in the same way as for <literal>\edit</literal>. + If you quit the editor without saving, the statement is discarded. + If you save and exit the editor, the updated command is executed immediately + if you added a semicolon to it. Otherwise it is redisplayed; + type semicolon or <literal>\g</literal> to send it, or <literal>\r</literal> + to cancel. + </para> + + <para> + If no view is specified, a blank <command>CREATE VIEW</command> + template is presented for editing. + </para> + + <para> + If a line number is specified, <application>psql</application> will + position the cursor on the specified line of the view definition. + </para> + + <para> + Unlike most other meta-commands, the entire remainder of the line is + always taken to be the argument(s) of <command>\ev</command>, and neither + variable interpolation nor backquote expansion are performed in the + arguments. + </para> + </listitem> + </varlistentry> + + + <varlistentry> + <term><literal>\f [ <replaceable class="parameter">string</replaceable> ]</literal></term> + + <listitem> + <para> + Sets the field separator for unaligned query output. The default + is the vertical bar (<literal>|</literal>). It is equivalent to + <command>\pset fieldsep</command>. + </para> + </listitem> + </varlistentry> + + + <varlistentry> + <term><literal>\g [ (<replaceable class="parameter">option</replaceable>=<replaceable class="parameter">value</replaceable> [...]) ] [ <replaceable class="parameter">filename</replaceable> ]</literal></term> + <term><literal>\g [ (<replaceable class="parameter">option</replaceable>=<replaceable class="parameter">value</replaceable> [...]) ] [ |<replaceable class="parameter">command</replaceable> ]</literal></term> + <listitem> + <para> + Sends the current query buffer to the server for execution. + </para> + <para> + If parentheses appear after <literal>\g</literal>, they surround a + space-separated list + of <replaceable class="parameter">option</replaceable><literal>=</literal><replaceable class="parameter">value</replaceable> + formatting-option clauses, which are interpreted in the same way + as <literal>\pset</literal> + <replaceable class="parameter">option</replaceable> + <replaceable class="parameter">value</replaceable> commands, but take + effect only for the duration of this query. In this list, spaces are + not allowed around <literal>=</literal> signs, but are required + between option clauses. + If <literal>=</literal><replaceable class="parameter">value</replaceable> + is omitted, the + named <replaceable class="parameter">option</replaceable> is changed + in the same way as for + <literal>\pset</literal> <replaceable class="parameter">option</replaceable> + with no explicit <replaceable class="parameter">value</replaceable>. + </para> + <para> + If a <replaceable class="parameter">filename</replaceable> + or <literal>|</literal><replaceable class="parameter">command</replaceable> + argument is given, the query's output is written to the named + file or piped to the given shell command, instead of displaying it as + usual. The file or command is written to only if the query + successfully returns zero or more tuples, not if the query fails or + is a non-data-returning SQL command. + </para> + <para> + If the current query buffer is empty, the most recently sent query is + re-executed instead. Except for that behavior, <literal>\g</literal> + without any arguments is essentially equivalent to a semicolon. + With arguments, <literal>\g</literal> provides + a <quote>one-shot</quote> alternative to the <command>\o</command> + command, and additionally allows one-shot adjustments of the + output formatting options normally set by <literal>\pset</literal>. + </para> + <para> + When the last argument begins with <literal>|</literal>, the entire + remainder of the line is taken to be + the <replaceable class="parameter">command</replaceable> to execute, + and neither variable interpolation nor backquote expansion are + performed in it. The rest of the line is simply passed literally to + the shell. + </para> + </listitem> + </varlistentry> + + + <varlistentry> + <term><literal>\gdesc</literal></term> + + <listitem> + <para> + Shows the description (that is, the column names and data types) + of the result of the current query buffer. The query is not + actually executed; however, if it contains some type of syntax + error, that error will be reported in the normal way. + </para> + + <para> + If the current query buffer is empty, the most recently sent query + is described instead. + </para> + </listitem> + </varlistentry> + + + <varlistentry> + <term><literal>\getenv <replaceable class="parameter">psql_var</replaceable> <replaceable class="parameter">env_var</replaceable></literal></term> + + <listitem> + <para> + Gets the value of the environment + variable <replaceable class="parameter">env_var</replaceable> + and assigns it to the <application>psql</application> + variable <replaceable class="parameter">psql_var</replaceable>. + If <replaceable class="parameter">env_var</replaceable> is + not defined in the <application>psql</application> process's + environment, <replaceable class="parameter">psql_var</replaceable> + is not changed. Example: +<programlisting> +=> <userinput>\getenv home HOME</userinput> +=> <userinput>\echo :home</userinput> +/home/postgres +</programlisting></para> + </listitem> + </varlistentry> + + + <varlistentry> + <term><literal>\gexec</literal></term> + + <listitem> + <para> + Sends the current query buffer to the server, then treats + each column of each row of the query's output (if any) as an SQL + statement to be executed. For example, to create an index on each + column of <structname>my_table</structname>: +<programlisting> +=> <userinput>SELECT format('create index on my_table(%I)', attname)</userinput> +-> <userinput>FROM pg_attribute</userinput> +-> <userinput>WHERE attrelid = 'my_table'::regclass AND attnum > 0</userinput> +-> <userinput>ORDER BY attnum</userinput> +-> <userinput>\gexec</userinput> +CREATE INDEX +CREATE INDEX +CREATE INDEX +CREATE INDEX +</programlisting> + </para> + + <para> + The generated queries are executed in the order in which the rows + are returned, and left-to-right within each row if there is more + than one column. NULL fields are ignored. The generated queries + are sent literally to the server for processing, so they cannot be + <application>psql</application> meta-commands nor contain <application>psql</application> + variable references. If any individual query fails, execution of + the remaining queries continues + unless <varname>ON_ERROR_STOP</varname> is set. Execution of each + query is subject to <varname>ECHO</varname> processing. + (Setting <varname>ECHO</varname> to <literal>all</literal> + or <literal>queries</literal> is often advisable when + using <command>\gexec</command>.) Query logging, single-step mode, + timing, and other query execution features apply to each generated + query as well. + </para> + <para> + If the current query buffer is empty, the most recently sent query + is re-executed instead. + </para> + </listitem> + </varlistentry> + + + <varlistentry> + <term><literal>\gset [ <replaceable class="parameter">prefix</replaceable> ]</literal></term> + + <listitem> + <para> + Sends the current query buffer to the server and stores the + query's output into <application>psql</application> variables + (see <xref linkend="app-psql-variables"/> below). + The query to be executed must return exactly one row. Each column of + the row is stored into a separate variable, named the same as the + column. For example: +<programlisting> +=> <userinput>SELECT 'hello' AS var1, 10 AS var2</userinput> +-> <userinput>\gset</userinput> +=> <userinput>\echo :var1 :var2</userinput> +hello 10 +</programlisting> + </para> + <para> + If you specify a <replaceable class="parameter">prefix</replaceable>, + that string is prepended to the query's column names to create the + variable names to use: +<programlisting> +=> <userinput>SELECT 'hello' AS var1, 10 AS var2</userinput> +-> <userinput>\gset result_</userinput> +=> <userinput>\echo :result_var1 :result_var2</userinput> +hello 10 +</programlisting> + </para> + <para> + If a column result is NULL, the corresponding variable is unset + rather than being set. + </para> + <para> + If the query fails or does not return one row, + no variables are changed. + </para> + <para> + If the current query buffer is empty, the most recently sent query + is re-executed instead. + </para> + </listitem> + </varlistentry> + + + <varlistentry> + <term><literal>\gx [ (<replaceable class="parameter">option</replaceable>=<replaceable class="parameter">value</replaceable> [...]) ] [ <replaceable class="parameter">filename</replaceable> ]</literal></term> + <term><literal>\gx [ (<replaceable class="parameter">option</replaceable>=<replaceable class="parameter">value</replaceable> [...]) ] [ |<replaceable class="parameter">command</replaceable> ]</literal></term> + <listitem> + <para> + <literal>\gx</literal> is equivalent to <literal>\g</literal>, except + that it forces expanded output mode for this query, as + if <literal>expanded=on</literal> were included in the list of + <literal>\pset</literal> options. See also <literal>\x</literal>. + </para> + </listitem> + </varlistentry> + + + <varlistentry> + <term><literal>\h</literal> or <literal>\help</literal> <literal>[ <replaceable class="parameter">command</replaceable> ]</literal></term> + <listitem> + <para> + Gives syntax help on the specified <acronym>SQL</acronym> + command. If <replaceable class="parameter">command</replaceable> + is not specified, then <application>psql</application> will list + all the commands for which syntax help is available. If + <replaceable class="parameter">command</replaceable> is an + asterisk (<literal>*</literal>), then syntax help on all + <acronym>SQL</acronym> commands is shown. + </para> + + <para> + Unlike most other meta-commands, the entire remainder of the line is + always taken to be the argument(s) of <command>\help</command>, and neither + variable interpolation nor backquote expansion are performed in the + arguments. + </para> + + <note> + <para> + To simplify typing, commands that consists of several words do + not have to be quoted. Thus it is fine to type <userinput>\help + alter table</userinput>. + </para> + </note> + </listitem> + </varlistentry> + + + <varlistentry> + <term><literal>\H</literal> or <literal>\html</literal></term> + <listitem> + <para> + Turns on <acronym>HTML</acronym> query output format. If the + <acronym>HTML</acronym> format is already on, it is switched + back to the default aligned text format. This command is for + compatibility and convenience, but see <command>\pset</command> + about setting other output options. + </para> + </listitem> + </varlistentry> + + + <varlistentry> + <term><literal>\i</literal> or <literal>\include</literal> <replaceable class="parameter">filename</replaceable></term> + <listitem> + <para> + Reads input from the file <replaceable + class="parameter">filename</replaceable> and executes it as + though it had been typed on the keyboard. + </para> + <para> + If <replaceable>filename</replaceable> is <literal>-</literal> + (hyphen), then standard input is read until an EOF indication + or <command>\q</command> meta-command. This can be used to intersperse + interactive input with input from files. Note that Readline behavior + will be used only if it is active at the outermost level. + </para> + <note> + <para> + If you want to see the lines on the screen as they are read you + must set the variable <varname>ECHO</varname> to + <literal>all</literal>. + </para> + </note> + </listitem> + </varlistentry> + + + <varlistentry id="psql-metacommand-if"> + <term><literal>\if</literal> <replaceable class="parameter">expression</replaceable></term> + <term><literal>\elif</literal> <replaceable class="parameter">expression</replaceable></term> + <term><literal>\else</literal></term> + <term><literal>\endif</literal></term> + <listitem> + <para> + This group of commands implements nestable conditional blocks. + A conditional block must begin with an <command>\if</command> and end + with an <command>\endif</command>. In between there may be any number + of <command>\elif</command> clauses, which may optionally be followed + by a single <command>\else</command> clause. Ordinary queries and + other types of backslash commands may (and usually do) appear between + the commands forming a conditional block. + </para> + <para> + The <command>\if</command> and <command>\elif</command> commands read + their argument(s) and evaluate them as a Boolean expression. If the + expression yields <literal>true</literal> then processing continues + normally; otherwise, lines are skipped until a + matching <command>\elif</command>, <command>\else</command>, + or <command>\endif</command> is reached. Once + an <command>\if</command> or <command>\elif</command> test has + succeeded, the arguments of later <command>\elif</command> commands in + the same block are not evaluated but are treated as false. Lines + following an <command>\else</command> are processed only if no earlier + matching <command>\if</command> or <command>\elif</command> succeeded. + </para> + <para> + The <replaceable class="parameter">expression</replaceable> argument + of an <command>\if</command> or <command>\elif</command> command + is subject to variable interpolation and backquote expansion, just + like any other backslash command argument. After that it is evaluated + like the value of an on/off option variable. So a valid value + is any unambiguous case-insensitive match for one of: + <literal>true</literal>, <literal>false</literal>, <literal>1</literal>, + <literal>0</literal>, <literal>on</literal>, <literal>off</literal>, + <literal>yes</literal>, <literal>no</literal>. For example, + <literal>t</literal>, <literal>T</literal>, and <literal>tR</literal> + will all be considered to be <literal>true</literal>. + </para> + <para> + Expressions that do not properly evaluate to true or false will + generate a warning and be treated as false. + </para> + <para> + Lines being skipped are parsed normally to identify queries and + backslash commands, but queries are not sent to the server, and + backslash commands other than conditionals + (<command>\if</command>, <command>\elif</command>, + <command>\else</command>, <command>\endif</command>) are + ignored. Conditional commands are checked only for valid nesting. + Variable references in skipped lines are not expanded, and backquote + expansion is not performed either. + </para> + <para> + All the backslash commands of a given conditional block must appear in + the same source file. If EOF is reached on the main input file or an + <command>\include</command>-ed file before all local + <command>\if</command>-blocks have been closed, + then <application>psql</application> will raise an error. + </para> + <para> + Here is an example: + </para> +<programlisting> +-- check for the existence of two separate records in the database and store +-- the results in separate psql variables +SELECT + EXISTS(SELECT 1 FROM customer WHERE customer_id = 123) as is_customer, + EXISTS(SELECT 1 FROM employee WHERE employee_id = 456) as is_employee +\gset +\if :is_customer + SELECT * FROM customer WHERE customer_id = 123; +\elif :is_employee + \echo 'is not a customer but is an employee' + SELECT * FROM employee WHERE employee_id = 456; +\else + \if yes + \echo 'not a customer or employee' + \else + \echo 'this will never print' + \endif +\endif +</programlisting> + </listitem> + </varlistentry> + + + <varlistentry> + <term><literal>\ir</literal> or <literal>\include_relative</literal> <replaceable class="parameter">filename</replaceable></term> + <listitem> + <para> + The <literal>\ir</literal> command is similar to <literal>\i</literal>, but resolves + relative file names differently. When executing in interactive mode, + the two commands behave identically. However, when invoked from a + script, <literal>\ir</literal> interprets file names relative to the + directory in which the script is located, rather than the current + working directory. + </para> + </listitem> + </varlistentry> + + + <varlistentry> + <term><literal>\l[+]</literal> or <literal>\list[+] [ <link linkend="app-psql-patterns"><replaceable class="parameter">pattern</replaceable></link> ]</literal></term> + <listitem> + <para> + List the databases in the server and show their names, owners, + character set encodings, and access privileges. + If <replaceable class="parameter">pattern</replaceable> is specified, + only databases whose names match the pattern are listed. + If <literal>+</literal> is appended to the command name, database + sizes, default tablespaces, and descriptions are also displayed. + (Size information is only available for databases that the current + user can connect to.) + </para> + </listitem> + </varlistentry> + + + <varlistentry> + <term><literal>\lo_export <replaceable class="parameter">loid</replaceable> <replaceable class="parameter">filename</replaceable></literal></term> + + <listitem> + <para> + Reads the large object with <acronym>OID</acronym> <replaceable + class="parameter">loid</replaceable> from the database and + writes it to <replaceable + class="parameter">filename</replaceable>. Note that this is + subtly different from the server function + <function>lo_export</function>, which acts with the permissions + of the user that the database server runs as and on the server's + file system. + </para> + <tip> + <para> + Use <command>\lo_list</command> to find out the large object's + <acronym>OID</acronym>. + </para> + </tip> + </listitem> + </varlistentry> + + + <varlistentry> + <term><literal>\lo_import <replaceable class="parameter">filename</replaceable> [ <replaceable class="parameter">comment</replaceable> ]</literal></term> + + <listitem> + <para> + Stores the file into a <productname>PostgreSQL</productname> + large object. Optionally, it associates the given + comment with the object. Example: +<programlisting> +foo=> <userinput>\lo_import '/home/peter/pictures/photo.xcf' 'a picture of me'</userinput> +lo_import 152801 +</programlisting> + The response indicates that the large object received object + ID 152801, which can be used to access the newly-created large + object in the future. For the sake of readability, it is + recommended to always associate a human-readable comment with + every object. Both OIDs and comments can be viewed with the + <command>\lo_list</command> command. + </para> + + <para> + Note that this command is subtly different from the server-side + <function>lo_import</function> because it acts as the local user + on the local file system, rather than the server's user and file + system. + </para> + </listitem> + </varlistentry> + + <varlistentry> + <term><literal>\lo_list[+]</literal></term> + <listitem> + <para> + Shows a list of all <productname>PostgreSQL</productname> + large objects currently stored in the database, + along with any comments provided for them. + If <literal>+</literal> is appended to the command name, + each large object is listed with its associated permissions, + if any. + </para> + </listitem> + </varlistentry> + + <varlistentry> + <term><literal>\lo_unlink <replaceable class="parameter">loid</replaceable></literal></term> + + <listitem> + <para> + Deletes the large object with <acronym>OID</acronym> + <replaceable class="parameter">loid</replaceable> from the + database. + </para> + + <tip> + <para> + Use <command>\lo_list</command> to find out the large object's + <acronym>OID</acronym>. + </para> + </tip> + </listitem> + </varlistentry> + + + <varlistentry> + <term><literal>\o</literal> or <literal>\out [ <replaceable class="parameter">filename</replaceable> ]</literal></term> + <term><literal>\o</literal> or <literal>\out [ |<replaceable class="parameter">command</replaceable> ]</literal></term> + <listitem> + <para> + Arranges to save future query results to the file <replaceable + class="parameter">filename</replaceable> or pipe future results + to the shell command <replaceable + class="parameter">command</replaceable>. If no argument is + specified, the query output is reset to the standard output. + </para> + + <para> + If the argument begins with <literal>|</literal>, then the entire remainder + of the line is taken to be + the <replaceable class="parameter">command</replaceable> to execute, + and neither variable interpolation nor backquote expansion are + performed in it. The rest of the line is simply passed literally to + the shell. + </para> + + <para> + <quote>Query results</quote> includes all tables, command + responses, and notices obtained from the database server, as + well as output of various backslash commands that query the + database (such as <command>\d</command>); but not error + messages. + </para> + + <tip> + <para> + To intersperse text output in between query results, use + <command>\qecho</command>. + </para> + </tip> + </listitem> + </varlistentry> + + + <varlistentry> + <term><literal>\p</literal> or <literal>\print</literal></term> + <listitem> + <para> + Print the current query buffer to the standard output. + If the current query buffer is empty, the most recently executed query + is printed instead. + </para> + </listitem> + </varlistentry> + + <varlistentry> + <term><literal>\password [ <replaceable class="parameter">username</replaceable> ]</literal></term> + <listitem> + <para> + Changes the password of the specified user (by default, the current + user). This command prompts for the new password, encrypts it, and + sends it to the server as an <command>ALTER ROLE</command> command. This + makes sure that the new password does not appear in cleartext in the + command history, the server log, or elsewhere. + </para> + </listitem> + </varlistentry> + + <varlistentry> + <term><literal>\prompt [ <replaceable class="parameter">text</replaceable> ] <replaceable class="parameter">name</replaceable></literal></term> + <listitem> + <para> + Prompts the user to supply text, which is assigned to the variable + <replaceable class="parameter">name</replaceable>. + An optional prompt string, <replaceable + class="parameter">text</replaceable>, can be specified. (For multiword + prompts, surround the text with single quotes.) + </para> + + <para> + By default, <literal>\prompt</literal> uses the terminal for input and + output. However, if the <option>-f</option> command line switch was + used, <literal>\prompt</literal> uses standard input and standard output. + </para> + </listitem> + </varlistentry> + + <varlistentry> + <term><literal>\pset [ <replaceable class="parameter">option</replaceable> [ <replaceable class="parameter">value</replaceable> ] ]</literal></term> + + <listitem> + <para> + This command sets options affecting the output of query result tables. + <replaceable class="parameter">option</replaceable> + indicates which option is to be set. The semantics of + <replaceable class="parameter">value</replaceable> vary depending + on the selected option. For some options, omitting <replaceable + class="parameter">value</replaceable> causes the option to be toggled + or unset, as described under the particular option. If no such + behavior is mentioned, then omitting + <replaceable class="parameter">value</replaceable> just results in + the current setting being displayed. + </para> + + <para> + <command>\pset</command> without any arguments displays the current status + of all printing options. + </para> + + <para> + Adjustable printing options are: + <variablelist> + <varlistentry> + <term><literal>border</literal></term> + <listitem> + <para> + The <replaceable class="parameter">value</replaceable> must be a + number. In general, the higher + the number the more borders and lines the tables will have, + but details depend on the particular format. + In <acronym>HTML</acronym> format, this will translate directly + into the <literal>border=...</literal> attribute. + In most other formats only values 0 (no border), 1 (internal + dividing lines), and 2 (table frame) make sense, and values above 2 + will be treated the same as <literal>border = 2</literal>. + The <literal>latex</literal> and <literal>latex-longtable</literal> + formats additionally allow a value of 3 to add dividing lines + between data rows. + </para> + </listitem> + </varlistentry> + + <varlistentry> + <term><literal>columns</literal></term> + <listitem> + <para> + Sets the target width for the <literal>wrapped</literal> format, and also + the width limit for determining whether output is wide enough to + require the pager or switch to the vertical display in expanded auto + mode. + Zero (the default) causes the target width to be controlled by the + environment variable <envar>COLUMNS</envar>, or the detected screen width + if <envar>COLUMNS</envar> is not set. + In addition, if <literal>columns</literal> is zero then the + <literal>wrapped</literal> format only affects screen output. + If <literal>columns</literal> is nonzero then file and pipe output is + wrapped to that width as well. + </para> + </listitem> + </varlistentry> + + <varlistentry> + <term><literal>csv_fieldsep</literal></term> + <listitem> + <para> + Specifies the field separator to be used in + <acronym>CSV</acronym> output format. If the separator character + appears in a field's value, that field is output within double + quotes, following standard <acronym>CSV</acronym> rules. + The default is a comma. + </para> + </listitem> + </varlistentry> + + <varlistentry> + <term><literal>expanded</literal> (or <literal>x</literal>)</term> + <listitem> + <para> + If <replaceable class="parameter">value</replaceable> is specified it + must be either <literal>on</literal> or <literal>off</literal>, which + will enable or disable expanded mode, or <literal>auto</literal>. + If <replaceable class="parameter">value</replaceable> is omitted the + command toggles between the on and off settings. When expanded mode + is enabled, query results are displayed in two columns, with the + column name on the left and the data on the right. This mode is + useful if the data wouldn't fit on the screen in the + normal <quote>horizontal</quote> mode. In the auto setting, the + expanded mode is used whenever the query output has more than one + column and is wider than the screen; otherwise, the regular mode is + used. The auto setting is only + effective in the aligned and wrapped formats. In other formats, it + always behaves as if the expanded mode is off. + </para> + </listitem> + </varlistentry> + + <varlistentry> + <term><literal>fieldsep</literal></term> + <listitem> + <para> + Specifies the field separator to be used in unaligned output + format. That way one can create, for example, tab-separated + output, which other programs might prefer. To + set a tab as field separator, type <literal>\pset fieldsep + '\t'</literal>. The default field separator is + <literal>'|'</literal> (a vertical bar). + </para> + </listitem> + </varlistentry> + + <varlistentry> + <term><literal>fieldsep_zero</literal></term> + <listitem> + <para> + Sets the field separator to use in unaligned output format to a zero + byte. + </para> + </listitem> + </varlistentry> + + <varlistentry> + <term><literal>footer</literal></term> + <listitem> + <para> + If <replaceable class="parameter">value</replaceable> is specified + it must be either <literal>on</literal> or <literal>off</literal> + which will enable or disable display of the table footer + (the <literal>(<replaceable>n</replaceable> rows)</literal> count). + If <replaceable class="parameter">value</replaceable> is omitted the + command toggles footer display on or off. + </para> + </listitem> + </varlistentry> + + <varlistentry> + <term><literal>format</literal></term> + <listitem> + <para> + Sets the output format to one of <literal>aligned</literal>, + <literal>asciidoc</literal>, + <literal>csv</literal>, + <literal>html</literal>, + <literal>latex</literal>, + <literal>latex-longtable</literal>, <literal>troff-ms</literal>, + <literal>unaligned</literal>, or <literal>wrapped</literal>. + Unique abbreviations are allowed. + </para> + + <para><literal>aligned</literal> format is the standard, + human-readable, nicely formatted text output; this is the default. + </para> + + <para><literal>unaligned</literal> format writes all columns of a row on one + line, separated by the currently active field separator. This + is useful for creating output that might be intended to be read + in by other programs, for example, tab-separated or comma-separated + format. However, the field separator character is not treated + specially if it appears in a column's value; + so <acronym>CSV</acronym> format may be better suited for such + purposes. + </para> + + <para><literal>csv</literal> format + <indexterm> + <primary>CSV (Comma-Separated Values) format</primary> + <secondary>in psql</secondary> + </indexterm> + writes column values separated by commas, applying the quoting + rules described in + <ulink url="https://tools.ietf.org/html/rfc4180">RFC 4180</ulink>. + This output is compatible with the CSV format of the server's + <command>COPY</command> command. + A header line with column names is generated unless + the <literal>tuples_only</literal> parameter is + <literal>on</literal>. Titles and footers are not printed. + Each row is terminated by the system-dependent end-of-line character, + which is typically a single newline (<literal>\n</literal>) for + Unix-like systems or a carriage return and newline sequence + (<literal>\r\n</literal>) for Microsoft Windows. + Field separator characters other than comma can be selected with + <command>\pset csv_fieldsep</command>. + </para> + + <para><literal>wrapped</literal> format is like <literal>aligned</literal> but wraps + wide data values across lines to make the output fit in the target + column width. The target width is determined as described under + the <literal>columns</literal> option. Note that <application>psql</application> will + not attempt to wrap column header titles; therefore, + <literal>wrapped</literal> format behaves the same as <literal>aligned</literal> + if the total width needed for column headers exceeds the target. + </para> + + <para> + The <literal>asciidoc</literal>, <literal>html</literal>, + <literal>latex</literal>, <literal>latex-longtable</literal>, and + <literal>troff-ms</literal> formats put out tables that are intended + to be included in documents using the respective mark-up + language. They are not complete documents! This might not be + necessary in <acronym>HTML</acronym>, but in + <application>LaTeX</application> you must have a complete + document wrapper. + The <literal>latex</literal> format + uses <application>LaTeX</application>'s <literal>tabular</literal> + environment. + The <literal>latex-longtable</literal> format + requires the <application>LaTeX</application> + <literal>longtable</literal> and <literal>booktabs</literal> packages. + </para> + </listitem> + </varlistentry> + + <varlistentry> + <term><literal>linestyle</literal></term> + <listitem> + <para> + Sets the border line drawing style to one + of <literal>ascii</literal>, <literal>old-ascii</literal>, + or <literal>unicode</literal>. + Unique abbreviations are allowed. (That would mean one + letter is enough.) + The default setting is <literal>ascii</literal>. + This option only affects the <literal>aligned</literal> and + <literal>wrapped</literal> output formats. + </para> + + <para><literal>ascii</literal> style uses plain <acronym>ASCII</acronym> + characters. Newlines in data are shown using + a <literal>+</literal> symbol in the right-hand margin. + When the <literal>wrapped</literal> format wraps data from + one line to the next without a newline character, a dot + (<literal>.</literal>) is shown in the right-hand margin of the first line, + and again in the left-hand margin of the following line. + </para> + + <para><literal>old-ascii</literal> style uses plain <acronym>ASCII</acronym> + characters, using the formatting style used + in <productname>PostgreSQL</productname> 8.4 and earlier. + Newlines in data are shown using a <literal>:</literal> + symbol in place of the left-hand column separator. + When the data is wrapped from one line + to the next without a newline character, a <literal>;</literal> + symbol is used in place of the left-hand column separator. + </para> + + <para><literal>unicode</literal> style uses Unicode box-drawing characters. + Newlines in data are shown using a carriage return symbol + in the right-hand margin. When the data is wrapped from one line + to the next without a newline character, an ellipsis symbol + is shown in the right-hand margin of the first line, and + again in the left-hand margin of the following line. + </para> + + <para> + When the <literal>border</literal> setting is greater than zero, + the <literal>linestyle</literal> option also determines the + characters with which the border lines are drawn. + Plain <acronym>ASCII</acronym> characters work everywhere, but + Unicode characters look nicer on displays that recognize them. + </para> + </listitem> + </varlistentry> + + <varlistentry> + <term><literal>null</literal></term> + <listitem> + <para> + Sets the string to be printed in place of a null value. + The default is to print nothing, which can easily be mistaken for + an empty string. For example, one might prefer <literal>\pset null + '(null)'</literal>. + </para> + </listitem> + </varlistentry> + + <varlistentry> + <term><literal>numericlocale</literal></term> + <listitem> + <para> + If <replaceable class="parameter">value</replaceable> is specified + it must be either <literal>on</literal> or <literal>off</literal> + which will enable or disable display of a locale-specific character + to separate groups of digits to the left of the decimal marker. + If <replaceable class="parameter">value</replaceable> is omitted the + command toggles between regular and locale-specific numeric output. + </para> + </listitem> + </varlistentry> + + <varlistentry> + <term><literal>pager</literal></term> + <listitem> + <para> + Controls use of a pager program for query and <application>psql</application> + help output. + When the <literal>pager</literal> option is <literal>off</literal>, the pager + program is not used. When the <literal>pager</literal> option is + <literal>on</literal>, the pager is used when appropriate, i.e., when the + output is to a terminal and will not fit on the screen. + The <literal>pager</literal> option can also be set to <literal>always</literal>, + which causes the pager to be used for all terminal output regardless + of whether it fits on the screen. <literal>\pset pager</literal> + without a <replaceable class="parameter">value</replaceable> + toggles pager use on and off. + </para> + + <para> + If the environment variable <envar>PSQL_PAGER</envar> + or <envar>PAGER</envar> is set, output to be paged is piped to the + specified program. Otherwise a platform-dependent default program + (such as <filename>more</filename>) is used. + </para> + + <para> + When using the <literal>\watch</literal> command to execute a query + repeatedly, the environment variable <envar>PSQL_WATCH_PAGER</envar> + is used to find the pager program instead, on Unix systems. This is + configured separately because it may confuse traditional pagers, but + can be used to send output to tools that understand + <application>psql</application>'s output format (such as + <filename>pspg --stream</filename>). + </para> + </listitem> + </varlistentry> + + <varlistentry> + <term><literal>pager_min_lines</literal></term> + <listitem> + <para> + If <literal>pager_min_lines</literal> is set to a number greater than the + page height, the pager program will not be called unless there are + at least this many lines of output to show. The default setting + is 0. + </para> + </listitem> + </varlistentry> + + <varlistentry> + <term><literal>recordsep</literal></term> + <listitem> + <para> + Specifies the record (line) separator to use in unaligned + output format. The default is a newline character. + </para> + </listitem> + </varlistentry> + + <varlistentry> + <term><literal>recordsep_zero</literal></term> + <listitem> + <para> + Sets the record separator to use in unaligned output format to a zero + byte. + </para> + </listitem> + </varlistentry> + + <varlistentry> + <term><literal>tableattr</literal> (or <literal>T</literal>)</term> + <listitem> + <para> + In <acronym>HTML</acronym> format, this specifies attributes + to be placed inside the <sgmltag>table</sgmltag> tag. This + could for example be <literal>cellpadding</literal> or + <literal>bgcolor</literal>. Note that you probably don't want + to specify <literal>border</literal> here, as that is already + taken care of by <literal>\pset border</literal>. + If no + <replaceable class="parameter">value</replaceable> is given, + the table attributes are unset. + </para> + <para> + In <literal>latex-longtable</literal> format, this controls + the proportional width of each column containing a left-aligned + data type. It is specified as a whitespace-separated list of values, + e.g., <literal>'0.2 0.2 0.6'</literal>. Unspecified output columns + use the last specified value. + </para> + </listitem> + </varlistentry> + + <varlistentry> + <term><literal>title</literal> (or <literal>C</literal>)</term> + <listitem> + <para> + Sets the table title for any subsequently printed tables. This + can be used to give your output descriptive tags. If no + <replaceable class="parameter">value</replaceable> is given, + the title is unset. + </para> + </listitem> + </varlistentry> + + <varlistentry> + <term><literal>tuples_only</literal> (or <literal>t</literal>)</term> + <listitem> + <para> + If <replaceable class="parameter">value</replaceable> is specified + it must be either <literal>on</literal> or <literal>off</literal> + which will enable or disable tuples-only mode. + If <replaceable class="parameter">value</replaceable> is omitted the + command toggles between regular and tuples-only output. + Regular output includes extra information such + as column headers, titles, and various footers. In tuples-only + mode, only actual table data is shown. + </para> + </listitem> + </varlistentry> + + <varlistentry> + <term><literal>unicode_border_linestyle</literal></term> + <listitem> + <para> + Sets the border drawing style for the <literal>unicode</literal> + line style to one of <literal>single</literal> + or <literal>double</literal>. + </para> + </listitem> + </varlistentry> + + <varlistentry> + <term><literal>unicode_column_linestyle</literal></term> + <listitem> + <para> + Sets the column drawing style for the <literal>unicode</literal> + line style to one of <literal>single</literal> + or <literal>double</literal>. + </para> + </listitem> + </varlistentry> + + <varlistentry> + <term><literal>unicode_header_linestyle</literal></term> + <listitem> + <para> + Sets the header drawing style for the <literal>unicode</literal> + line style to one of <literal>single</literal> + or <literal>double</literal>. + </para> + </listitem> + </varlistentry> + </variablelist> + </para> + + <para> + Illustrations of how these different formats look can be seen in + <xref linkend="app-psql-examples"/>, below. + </para> + + <tip> + <para> + There are various shortcut commands for <command>\pset</command>. See + <command>\a</command>, <command>\C</command>, <command>\f</command>, + <command>\H</command>, <command>\t</command>, <command>\T</command>, + and <command>\x</command>. + </para> + </tip> + + </listitem> + </varlistentry> + + + <varlistentry> + <term><literal>\q</literal> or <literal>\quit</literal></term> + <listitem> + <para> + Quits the <application>psql</application> program. + In a script file, only execution of that script is terminated. + </para> + </listitem> + </varlistentry> + + + <varlistentry> + <term><literal>\qecho <replaceable class="parameter">text</replaceable> [ ... ] </literal></term> + <listitem> + <para> + This command is identical to <command>\echo</command> except + that the output will be written to the query output channel, as + set by <command>\o</command>. + </para> + </listitem> + </varlistentry> + + + <varlistentry> + <term><literal>\r</literal> or <literal>\reset</literal></term> + <listitem> + <para> + Resets (clears) the query buffer. + </para> + </listitem> + </varlistentry> + + + <varlistentry> + <term><literal>\s [ <replaceable class="parameter">filename</replaceable> ]</literal></term> + <listitem> + <para> + Print <application>psql</application>'s command line history + to <replaceable class="parameter">filename</replaceable>. + If <replaceable class="parameter">filename</replaceable> is omitted, + the history is written to the standard output (using the pager if + appropriate). This command is not available + if <application>psql</application> was built + without <application>Readline</application> support. + </para> + </listitem> + </varlistentry> + + + <varlistentry> + <term><literal>\set [ <replaceable class="parameter">name</replaceable> [ <replaceable class="parameter">value</replaceable> [ ... ] ] ]</literal></term> + + <listitem> + <para> + Sets the <application>psql</application> variable <replaceable + class="parameter">name</replaceable> to <replaceable + class="parameter">value</replaceable>, or if more than one value + is given, to the concatenation of all of them. If only one + argument is given, the variable is set to an empty-string value. To + unset a variable, use the <command>\unset</command> command. + </para> + + <para><command>\set</command> without any arguments displays the names and values + of all currently-set <application>psql</application> variables. + </para> + + <para> + Valid variable names can contain letters, digits, and + underscores. See <xref linkend="app-psql-variables"/> below for details. + Variable names are case-sensitive. + </para> + + <para> + Certain variables are special, in that they + control <application>psql</application>'s behavior or are + automatically set to reflect connection state. These variables are + documented in <xref linkend="app-psql-variables"/>, below. + </para> + + <note> + <para> + This command is unrelated to the <acronym>SQL</acronym> + command <link linkend="sql-set"><command>SET</command></link>. + </para> + </note> + </listitem> + </varlistentry> + + + <varlistentry> + <term><literal>\setenv <replaceable class="parameter">name</replaceable> [ <replaceable class="parameter">value</replaceable> ]</literal></term> + + <listitem> + <para> + Sets the environment variable <replaceable + class="parameter">name</replaceable> to <replaceable + class="parameter">value</replaceable>, or if the + <replaceable class="parameter">value</replaceable> is + not supplied, unsets the environment variable. Example: +<programlisting> +testdb=> <userinput>\setenv PAGER less</userinput> +testdb=> <userinput>\setenv LESS -imx4F</userinput> +</programlisting></para> + </listitem> + </varlistentry> + + <varlistentry> + <term><literal>\sf[+] <replaceable class="parameter">function_description</replaceable> </literal></term> + + <listitem> + <para> + This command fetches and shows the definition of the named function or procedure, + in the form of a <command>CREATE OR REPLACE FUNCTION</command> or + <command>CREATE OR REPLACE PROCEDURE</command> command. + The definition is printed to the current query output channel, + as set by <command>\o</command>. + </para> + + <para> + The target function can be specified by name alone, or by name + and arguments, for example <literal>foo(integer, text)</literal>. + The argument types must be given if there is more + than one function of the same name. + </para> + + <para> + If <literal>+</literal> is appended to the command name, then the + output lines are numbered, with the first line of the function body + being line 1. + </para> + + <para> + Unlike most other meta-commands, the entire remainder of the line is + always taken to be the argument(s) of <command>\sf</command>, and neither + variable interpolation nor backquote expansion are performed in the + arguments. + </para> + </listitem> + </varlistentry> + + + <varlistentry> + <term><literal>\sv[+] <replaceable class="parameter">view_name</replaceable> </literal></term> + + <listitem> + <para> + This command fetches and shows the definition of the named view, + in the form of a <command>CREATE OR REPLACE VIEW</command> command. + The definition is printed to the current query output channel, + as set by <command>\o</command>. + </para> + + <para> + If <literal>+</literal> is appended to the command name, then the + output lines are numbered from 1. + </para> + + <para> + Unlike most other meta-commands, the entire remainder of the line is + always taken to be the argument(s) of <command>\sv</command>, and neither + variable interpolation nor backquote expansion are performed in the + arguments. + </para> + </listitem> + </varlistentry> + + + <varlistentry> + <term><literal>\t</literal></term> + <listitem> + <para> + Toggles the display of output column name headings and row count + footer. This command is equivalent to <literal>\pset + tuples_only</literal> and is provided for convenience. + </para> + </listitem> + </varlistentry> + + + <varlistentry> + <term><literal>\T <replaceable class="parameter">table_options</replaceable></literal></term> + <listitem> + <para> + Specifies attributes to be placed within the + <sgmltag>table</sgmltag> tag in <acronym>HTML</acronym> + output format. This command is equivalent to <literal>\pset + tableattr <replaceable + class="parameter">table_options</replaceable></literal>. + </para> + </listitem> + </varlistentry> + + + <varlistentry> + <term><literal>\timing [ <replaceable class="parameter">on</replaceable> | <replaceable class="parameter">off</replaceable> ]</literal></term> + <listitem> + <para> + With a parameter, turns displaying of how long each SQL statement + takes on or off. Without a parameter, toggles the display between + on and off. The display is in milliseconds; intervals longer than + 1 second are also shown in minutes:seconds format, with hours and + days fields added if needed. + </para> + </listitem> + </varlistentry> + + + <varlistentry> + <term><literal>\unset <replaceable class="parameter">name</replaceable></literal></term> + + <listitem> + <para> + Unsets (deletes) the <application>psql</application> variable <replaceable + class="parameter">name</replaceable>. + </para> + + <para> + Most variables that control <application>psql</application>'s behavior + cannot be unset; instead, an <literal>\unset</literal> command is interpreted + as setting them to their default values. + See <xref linkend="app-psql-variables"/> below. + </para> + </listitem> + </varlistentry> + + + <varlistentry> + <term><literal>\w</literal> or <literal>\write</literal> <replaceable class="parameter">filename</replaceable></term> + <term><literal>\w</literal> or <literal>\write</literal> <literal>|</literal><replaceable class="parameter">command</replaceable></term> + <listitem> + <para> + Writes the current query buffer to the file <replaceable + class="parameter">filename</replaceable> or pipes it to the shell + command <replaceable class="parameter">command</replaceable>. + If the current query buffer is empty, the most recently executed query + is written instead. + </para> + + <para> + If the argument begins with <literal>|</literal>, then the entire remainder + of the line is taken to be + the <replaceable class="parameter">command</replaceable> to execute, + and neither variable interpolation nor backquote expansion are + performed in it. The rest of the line is simply passed literally to + the shell. + </para> + </listitem> + </varlistentry> + + + <varlistentry> + <term><literal>\warn <replaceable class="parameter">text</replaceable> [ ... ]</literal></term> + <listitem> + <para> + This command is identical to <command>\echo</command> except + that the output will be written to <application>psql</application>'s + standard error channel, rather than standard output. + </para> + </listitem> + </varlistentry> + + + <varlistentry> + <term><literal>\watch [ <replaceable class="parameter">seconds</replaceable> ]</literal></term> + <listitem> + <para> + Repeatedly execute the current query buffer (as <literal>\g</literal> does) + until interrupted or the query fails. Wait the specified number of + seconds (default 2) between executions. Each query result is + displayed with a header that includes the <literal>\pset title</literal> + string (if any), the time as of query start, and the delay interval. + </para> + <para> + If the current query buffer is empty, the most recently sent query + is re-executed instead. + </para> + </listitem> + </varlistentry> + + + <varlistentry> + <term><literal>\x [ <replaceable class="parameter">on</replaceable> | <replaceable class="parameter">off</replaceable> | <replaceable class="parameter">auto</replaceable> ]</literal></term> + <listitem> + <para> + Sets or toggles expanded table formatting mode. As such it is equivalent to + <literal>\pset expanded</literal>. + </para> + </listitem> + </varlistentry> + + + <varlistentry> + <term><literal>\z [ <link linkend="app-psql-patterns"><replaceable class="parameter">pattern</replaceable></link> ]</literal></term> + <listitem> + <para> + Lists tables, views and sequences with their + associated access privileges. + If a <replaceable class="parameter">pattern</replaceable> is + specified, only tables, views and sequences whose names match the + pattern are listed. + </para> + + <para> + This is an alias for <command>\dp</command> (<quote>display + privileges</quote>). + </para> + </listitem> + </varlistentry> + + + <varlistentry> + <term><literal>\! [ <replaceable class="parameter">command</replaceable> ]</literal></term> + <listitem> + <para> + With no argument, escapes to a sub-shell; <application>psql</application> + resumes when the sub-shell exits. With an argument, executes the + shell command <replaceable class="parameter">command</replaceable>. + </para> + + <para> + Unlike most other meta-commands, the entire remainder of the line is + always taken to be the argument(s) of <command>\!</command>, and neither + variable interpolation nor backquote expansion are performed in the + arguments. The rest of the line is simply passed literally to the + shell. + </para> + </listitem> + </varlistentry> + + + <varlistentry> + <term><literal>\? [ <replaceable class="parameter">topic</replaceable> ]</literal></term> + <listitem> + <para> + Shows help information. The optional + <replaceable class="parameter">topic</replaceable> parameter + (defaulting to <literal>commands</literal>) selects which part of <application>psql</application> is + explained: <literal>commands</literal> describes <application>psql</application>'s + backslash commands; <literal>options</literal> describes the command-line + options that can be passed to <application>psql</application>; + and <literal>variables</literal> shows help about <application>psql</application> configuration + variables. + </para> + </listitem> + </varlistentry> + + + <varlistentry> + <term><literal>\;</literal></term> + <listitem> + <para> + Backslash-semicolon is not a meta-command in the same way as the + preceding commands; rather, it simply causes a semicolon to be + added to the query buffer without any further processing. + </para> + + <para> + Normally, <application>psql</application> will dispatch an SQL command to the + server as soon as it reaches the command-ending semicolon, even if + more input remains on the current line. Thus for example entering +<programlisting> +select 1; select 2; select 3; +</programlisting> + will result in the three SQL commands being individually sent to + the server, with each one's results being displayed before + continuing to the next command. However, a semicolon entered + as <literal>\;</literal> will not trigger command processing, so that the + command before it and the one after are effectively combined and + sent to the server in one request. So for example +<programlisting> +select 1\; select 2\; select 3; +</programlisting> + results in sending the three SQL commands to the server in a single + request, when the non-backslashed semicolon is reached. + The server executes such a request as a single transaction, + unless there are explicit <command>BEGIN</command>/<command>COMMIT</command> + commands included in the string to divide it into multiple + transactions. (See <xref linkend="protocol-flow-multi-statement"/> + for more details about how the server handles multi-query strings.) + </para> + </listitem> + </varlistentry> + + </variablelist> + </para> + + <refsect3 id="app-psql-patterns" xreflabel="Patterns"> + <title>Patterns</title> + + <indexterm> + <primary>patterns</primary> + <secondary>in psql and pg_dump</secondary> + </indexterm> + + <para> + The various <literal>\d</literal> commands accept a <replaceable + class="parameter">pattern</replaceable> parameter to specify the + object name(s) to be displayed. In the simplest case, a pattern + is just the exact name of the object. The characters within a + pattern are normally folded to lower case, just as in SQL names; + for example, <literal>\dt FOO</literal> will display the table named + <literal>foo</literal>. As in SQL names, placing double quotes around + a pattern stops folding to lower case. Should you need to include + an actual double quote character in a pattern, write it as a pair + of double quotes within a double-quote sequence; again this is in + accord with the rules for SQL quoted identifiers. For example, + <literal>\dt "FOO""BAR"</literal> will display the table named + <literal>FOO"BAR</literal> (not <literal>foo"bar</literal>). Unlike the normal + rules for SQL names, you can put double quotes around just part + of a pattern, for instance <literal>\dt FOO"FOO"BAR</literal> will display + the table named <literal>fooFOObar</literal>. + </para> + + <para> + Whenever the <replaceable class="parameter">pattern</replaceable> parameter + is omitted completely, the <literal>\d</literal> commands display all objects + that are visible in the current schema search path — this is + equivalent to using <literal>*</literal> as the pattern. + (An object is said to be <firstterm>visible</firstterm> if its + containing schema is in the search path and no object of the same + kind and name appears earlier in the search path. This is equivalent to the + statement that the object can be referenced by name without explicit + schema qualification.) + To see all objects in the database regardless of visibility, + use <literal>*.*</literal> as the pattern. + </para> + + <para> + Within a pattern, <literal>*</literal> matches any sequence of characters + (including no characters) and <literal>?</literal> matches any single character. + (This notation is comparable to Unix shell file name patterns.) + For example, <literal>\dt int*</literal> displays tables whose names + begin with <literal>int</literal>. But within double quotes, <literal>*</literal> + and <literal>?</literal> lose these special meanings and are just matched + literally. + </para> + + <para> + A relation pattern that contains a dot (<literal>.</literal>) is interpreted as a schema + name pattern followed by an object name pattern. For example, + <literal>\dt foo*.*bar*</literal> displays all tables whose table name + includes <literal>bar</literal> that are in schemas whose schema name + starts with <literal>foo</literal>. When no dot appears, then the pattern + matches only objects that are visible in the current schema search path. + Again, a dot within double quotes loses its special meaning and is matched + literally. A relation pattern that contains two dots (<literal>.</literal>) + is interpreted as a database name followed by a schema name pattern followed + by an object name pattern. The database name portion will not be treated as + a pattern and must match the name of the currently connected database, else + an error will be raised. + </para> + + <para> + A schema pattern that contains a dot (<literal>.</literal>) is interpreted + as a database name followed by a schema name pattern. For example, + <literal>\dn mydb.*foo*</literal> displays all schemas whose schema name + includes <literal>foo</literal>. The database name portion will not be + treated as a pattern and must match the name of the currently connected + database, else an error will be raised. + </para> + + <para> + Advanced users can use regular-expression notations such as character + classes, for example <literal>[0-9]</literal> to match any digit. All regular + expression special characters work as specified in + <xref linkend="functions-posix-regexp"/>, except for <literal>.</literal> which + is taken as a separator as mentioned above, <literal>*</literal> which is + translated to the regular-expression notation <literal>.*</literal>, + <literal>?</literal> which is translated to <literal>.</literal>, and + <literal>$</literal> which is matched literally. You can emulate + these pattern characters at need by writing + <literal>?</literal> for <literal>.</literal>, + <literal>(<replaceable class="parameter">R</replaceable>+|)</literal> for + <literal><replaceable class="parameter">R</replaceable>*</literal>, or + <literal>(<replaceable class="parameter">R</replaceable>|)</literal> for + <literal><replaceable class="parameter">R</replaceable>?</literal>. + <literal>$</literal> is not needed as a regular-expression character since + the pattern must match the whole name, unlike the usual + interpretation of regular expressions (in other words, <literal>$</literal> + is automatically appended to your pattern). Write <literal>*</literal> at the + beginning and/or end if you don't wish the pattern to be anchored. + Note that within double quotes, all regular expression special characters + lose their special meanings and are matched literally. Also, the regular + expression special characters are matched literally in operator name + patterns (i.e., the argument of <literal>\do</literal>). + </para> + </refsect3> + </refsect2> + + <refsect2> + <title>Advanced Features</title> + + <refsect3 id="app-psql-variables" xreflabel="Variables"> + <title>Variables</title> + + <para> + <application>psql</application> provides variable substitution + features similar to common Unix command shells. + Variables are simply name/value pairs, where the value + can be any string of any length. The name must consist of letters + (including non-Latin letters), digits, and underscores. + </para> + + <para> + To set a variable, use the <application>psql</application> meta-command + <command>\set</command>. For example, +<programlisting> +testdb=> <userinput>\set foo bar</userinput> +</programlisting> + sets the variable <literal>foo</literal> to the value + <literal>bar</literal>. To retrieve the content of the variable, precede + the name with a colon, for example: +<programlisting> +testdb=> <userinput>\echo :foo</userinput> +bar +</programlisting> + This works in both regular SQL commands and meta-commands; there is + more detail in <xref linkend="app-psql-interpolation"/>, below. + </para> + + <para> + If you call <command>\set</command> without a second argument, the + variable is set to an empty-string value. To unset (i.e., delete) + a variable, use the command <command>\unset</command>. To show the + values of all variables, call <command>\set</command> without any argument. + </para> + + <note> + <para> + The arguments of <command>\set</command> are subject to the same + substitution rules as with other commands. Thus you can construct + interesting references such as <literal>\set :foo + 'something'</literal> and get <quote>soft links</quote> or + <quote>variable variables</quote> of <productname>Perl</productname> + or <productname><acronym>PHP</acronym></productname> fame, + respectively. Unfortunately (or fortunately?), there is no way to do + anything useful with these constructs. On the other hand, + <literal>\set bar :foo</literal> is a perfectly valid way to copy a + variable. + </para> + </note> + + <para> + A number of these variables are treated specially + by <application>psql</application>. They represent certain option + settings that can be changed at run time by altering the value of + the variable, or in some cases represent changeable state of + <application>psql</application>. + By convention, all specially treated variables' names + consist of all upper-case ASCII letters (and possibly digits and + underscores). To ensure maximum compatibility in the future, avoid + using such variable names for your own purposes. + </para> + + <para> + Variables that control <application>psql</application>'s behavior + generally cannot be unset or set to invalid values. An <literal>\unset</literal> + command is allowed but is interpreted as setting the variable to its + default value. A <literal>\set</literal> command without a second argument is + interpreted as setting the variable to <literal>on</literal>, for control + variables that accept that value, and is rejected for others. Also, + control variables that accept the values <literal>on</literal> + and <literal>off</literal> will also accept other common spellings of Boolean + values, such as <literal>true</literal> and <literal>false</literal>. + </para> + + <para> + The specially treated variables are: + </para> + + <variablelist> + <varlistentry> + <term> + <varname>AUTOCOMMIT</varname> + <indexterm> + <primary>autocommit</primary> + <secondary>psql</secondary> + </indexterm> + </term> + <listitem> + <para> + When <literal>on</literal> (the default), each SQL command is automatically + committed upon successful completion. To postpone commit in this + mode, you must enter a <command>BEGIN</command> or <command>START + TRANSACTION</command> SQL command. When <literal>off</literal> or unset, SQL + commands are not committed until you explicitly issue + <command>COMMIT</command> or <command>END</command>. The autocommit-off + mode works by issuing an implicit <command>BEGIN</command> for you, just + before any command that is not already in a transaction block and + is not itself a <command>BEGIN</command> or other transaction-control + command, nor a command that cannot be executed inside a transaction + block (such as <command>VACUUM</command>). + </para> + + <note> + <para> + In autocommit-off mode, you must explicitly abandon any failed + transaction by entering <command>ABORT</command> or <command>ROLLBACK</command>. + Also keep in mind that if you exit the session + without committing, your work will be lost. + </para> + </note> + + <note> + <para> + The autocommit-on mode is <productname>PostgreSQL</productname>'s traditional + behavior, but autocommit-off is closer to the SQL spec. If you + prefer autocommit-off, you might wish to set it in the system-wide + <filename>psqlrc</filename> file or your + <filename>~/.psqlrc</filename> file. + </para> + </note> + </listitem> + </varlistentry> + + <varlistentry> + <term><varname>COMP_KEYWORD_CASE</varname></term> + <listitem> + <para> + Determines which letter case to use when completing an SQL key word. + If set to <literal>lower</literal> or <literal>upper</literal>, the + completed word will be in lower or upper case, respectively. If set + to <literal>preserve-lower</literal> + or <literal>preserve-upper</literal> (the default), the completed word + will be in the case of the word already entered, but words being + completed without anything entered will be in lower or upper case, + respectively. + </para> + </listitem> + </varlistentry> + + <varlistentry> + <term><varname>DBNAME</varname></term> + <listitem> + <para> + The name of the database you are currently connected to. This is + set every time you connect to a database (including program + start-up), but can be changed or unset. + </para> + </listitem> + </varlistentry> + + <varlistentry> + <term><varname>ECHO</varname></term> + <listitem> + <para> + If set to <literal>all</literal>, all nonempty input lines are printed + to standard output as they are read. (This does not apply to lines + read interactively.) To select this behavior on program + start-up, use the switch <option>-a</option>. If set to + <literal>queries</literal>, + <application>psql</application> prints each query to standard output + as it is sent to the server. The switch to select this behavior is + <option>-e</option>. If set to <literal>errors</literal>, then only + failed queries are displayed on standard error output. The switch + for this behavior is <option>-b</option>. If set to + <literal>none</literal> (the default), then no queries are displayed. + </para> + </listitem> + </varlistentry> + + <varlistentry> + <term><varname>ECHO_HIDDEN</varname></term> + <listitem> + <para> + When this variable is set to <literal>on</literal> and a backslash command + queries the database, the query is first shown. + This feature helps you to study + <productname>PostgreSQL</productname> internals and provide + similar functionality in your own programs. (To select this behavior + on program start-up, use the switch <option>-E</option>.) If you set + this variable to the value <literal>noexec</literal>, the queries are + just shown but are not actually sent to the server and executed. + The default value is <literal>off</literal>. + </para> + </listitem> + </varlistentry> + + <varlistentry> + <term><varname>ENCODING</varname></term> + <listitem> + <para> + The current client character set encoding. + This is set every time you connect to a database (including + program start-up), and when you change the encoding + with <literal>\encoding</literal>, but it can be changed or unset. + </para> + </listitem> + </varlistentry> + + <varlistentry> + <term><varname>ERROR</varname></term> + <listitem> + <para> + <literal>true</literal> if the last SQL query failed, <literal>false</literal> if + it succeeded. See also <varname>SQLSTATE</varname>. + </para> + </listitem> + </varlistentry> + + <varlistentry> + <term><varname>FETCH_COUNT</varname></term> + <listitem> + <para> + If this variable is set to an integer value greater than zero, + the results of <command>SELECT</command> queries are fetched + and displayed in groups of that many rows, rather than the + default behavior of collecting the entire result set before + display. Therefore only a + limited amount of memory is used, regardless of the size of + the result set. Settings of 100 to 1000 are commonly used + when enabling this feature. + Keep in mind that when using this feature, a query might + fail after having already displayed some rows. + </para> + + <tip> + <para> + Although you can use any output format with this feature, + the default <literal>aligned</literal> format tends to look bad + because each group of <varname>FETCH_COUNT</varname> rows + will be formatted separately, leading to varying column + widths across the row groups. The other output formats work better. + </para> + </tip> + </listitem> + </varlistentry> + + <varlistentry> + <term><varname>HIDE_TABLEAM</varname></term> + <listitem> + <para> + If this variable is set to <literal>true</literal>, a table's access + method details are not displayed. This is mainly useful for + regression tests. + </para> + </listitem> + </varlistentry> + + <varlistentry> + <term><varname>HIDE_TOAST_COMPRESSION</varname></term> + <listitem> + <para> + If this variable is set to <literal>true</literal>, column + compression method details are not displayed. This is mainly + useful for regression tests. + </para> + </listitem> + </varlistentry> + + <varlistentry> + <term><varname>HISTCONTROL</varname></term> + <listitem> + <para> + If this variable is set to <literal>ignorespace</literal>, + lines which begin with a space are not entered into the history + list. If set to a value of <literal>ignoredups</literal>, lines + matching the previous history line are not entered. A value of + <literal>ignoreboth</literal> combines the two options. If + set to <literal>none</literal> (the default), all lines + read in interactive mode are saved on the history list. + </para> + <note> + <para> + This feature was shamelessly plagiarized from + <application>Bash</application>. + </para> + </note> + </listitem> + </varlistentry> + + <varlistentry> + <term><varname>HISTFILE</varname></term> + <listitem> + <para> + The file name that will be used to store the history list. If unset, + the file name is taken from the <envar>PSQL_HISTORY</envar> + environment variable. If that is not set either, the default + is <filename>~/.psql_history</filename>, + or <filename>%APPDATA%\postgresql\psql_history</filename> on Windows. + For example, putting: +<programlisting> +\set HISTFILE ~/.psql_history-:DBNAME +</programlisting> + in <filename>~/.psqlrc</filename> will cause + <application>psql</application> to maintain a separate history for + each database. + </para> + <note> + <para> + This feature was shamelessly plagiarized from + <application>Bash</application>. + </para> + </note> + </listitem> + </varlistentry> + + <varlistentry> + <term><varname>HISTSIZE</varname></term> + <listitem> + <para> + The maximum number of commands to store in the command history + (default 500). If set to a negative value, no limit is applied. + </para> + <note> + <para> + This feature was shamelessly plagiarized from + <application>Bash</application>. + </para> + </note> + </listitem> + </varlistentry> + + <varlistentry> + <term><varname>HOST</varname></term> + <listitem> + <para> + The database server host you are currently connected to. This is + set every time you connect to a database (including program + start-up), but can be changed or unset. + </para> + </listitem> + </varlistentry> + + <varlistentry> + <term><varname>IGNOREEOF</varname></term> + <listitem> + <para> + If set to 1 or less, sending an <acronym>EOF</acronym> character (usually + <keycombo action="simul"><keycap>Control</keycap><keycap>D</keycap></keycombo>) + to an interactive session of <application>psql</application> + will terminate the application. If set to a larger numeric value, + that many consecutive <acronym>EOF</acronym> characters must be typed to + make an interactive session terminate. If the variable is set to a + non-numeric value, it is interpreted as 10. The default is 0. + </para> + <note> + <para> + This feature was shamelessly plagiarized from + <application>Bash</application>. + </para> + </note> + </listitem> + </varlistentry> + + <varlistentry> + <term><varname>LASTOID</varname></term> + <listitem> + <para> + The value of the last affected OID, as returned from an + <command>INSERT</command> or <command>\lo_import</command> + command. This variable is only guaranteed to be valid until + after the result of the next <acronym>SQL</acronym> command has + been displayed. + <productname>PostgreSQL</productname> servers since version 12 do not + support OID system columns anymore, thus LASTOID will always be 0 + following <command>INSERT</command> when targeting such servers. + </para> + </listitem> + </varlistentry> + + <varlistentry> + <term><varname>LAST_ERROR_MESSAGE</varname></term> + <term><varname>LAST_ERROR_SQLSTATE</varname></term> + <listitem> + <para> + The primary error message and associated SQLSTATE code for the most + recent failed query in the current <application>psql</application> session, or + an empty string and <literal>00000</literal> if no error has occurred in + the current session. + </para> + </listitem> + </varlistentry> + + <varlistentry> + <term> + <varname>ON_ERROR_ROLLBACK</varname> + <indexterm> + <primary>rollback</primary> + <secondary>psql</secondary> + </indexterm> + </term> + <listitem> + <para> + When set to <literal>on</literal>, if a statement in a transaction block + generates an error, the error is ignored and the transaction + continues. When set to <literal>interactive</literal>, such errors are only + ignored in interactive sessions, and not when reading script + files. When set to <literal>off</literal> (the default), a statement in a + transaction block that generates an error aborts the entire + transaction. The error rollback mode works by issuing an + implicit <command>SAVEPOINT</command> for you, just before each command + that is in a transaction block, and then rolling back to the + savepoint if the command fails. + </para> + </listitem> + </varlistentry> + + <varlistentry> + <term><varname>ON_ERROR_STOP</varname></term> + <listitem> + <para> + By default, command processing continues after an error. When this + variable is set to <literal>on</literal>, processing will instead stop + immediately. In interactive mode, + <application>psql</application> will return to the command prompt; + otherwise, <application>psql</application> will exit, returning + error code 3 to distinguish this case from fatal error + conditions, which are reported using error code 1. In either case, + any currently running scripts (the top-level script, if any, and any + other scripts which it may have in invoked) will be terminated + immediately. If the top-level command string contained multiple SQL + commands, processing will stop with the current command. + </para> + </listitem> + </varlistentry> + + <varlistentry> + <term><varname>PORT</varname></term> + <listitem> + <para> + The database server port to which you are currently connected. + This is set every time you connect to a database (including + program start-up), but can be changed or unset. + </para> + </listitem> + </varlistentry> + + <varlistentry> + <term><varname>PROMPT1</varname></term> + <term><varname>PROMPT2</varname></term> + <term><varname>PROMPT3</varname></term> + <listitem> + <para> + These specify what the prompts <application>psql</application> + issues should look like. See <xref + linkend="app-psql-prompting"/> below. + </para> + </listitem> + </varlistentry> + + <varlistentry> + <term><varname>QUIET</varname></term> + <listitem> + <para> + Setting this variable to <literal>on</literal> is equivalent to the command + line option <option>-q</option>. It is probably not too useful in + interactive mode. + </para> + </listitem> + </varlistentry> + + <varlistentry> + <term><varname>ROW_COUNT</varname></term> + <listitem> + <para> + The number of rows returned or affected by the last SQL query, or 0 + if the query failed or did not report a row count. + </para> + </listitem> + </varlistentry> + + <varlistentry> + <term><varname>SERVER_VERSION_NAME</varname></term> + <term><varname>SERVER_VERSION_NUM</varname></term> + <listitem> + <para> + The server's version number as a string, for + example <literal>9.6.2</literal>, <literal>10.1</literal> or <literal>11beta1</literal>, + and in numeric form, for + example <literal>90602</literal> or <literal>100001</literal>. + These are set every time you connect to a database + (including program start-up), but can be changed or unset. + </para> + </listitem> + </varlistentry> + + <varlistentry> + <term><varname>SHOW_ALL_RESULTS</varname></term> + <listitem> + <para> + When this variable is set to <literal>off</literal>, only the last + result of a combined query (<literal>\;</literal>) is shown instead of + all of them. The default is <literal>on</literal>. The off behavior + is for compatibility with older versions of psql. + </para> + </listitem> + </varlistentry> + + <varlistentry> + <term><varname>SHOW_CONTEXT</varname></term> + <listitem> + <para> + This variable can be set to the + values <literal>never</literal>, <literal>errors</literal>, or <literal>always</literal> + to control whether <literal>CONTEXT</literal> fields are displayed in + messages from the server. The default is <literal>errors</literal> (meaning + that context will be shown in error messages, but not in notice or + warning messages). This setting has no effect + when <varname>VERBOSITY</varname> is set to <literal>terse</literal> + or <literal>sqlstate</literal>. + (See also <command>\errverbose</command>, for use when you want a verbose + version of the error you just got.) + </para> + </listitem> + </varlistentry> + + <varlistentry> + <term><varname>SINGLELINE</varname></term> + <listitem> + <para> + Setting this variable to <literal>on</literal> is equivalent to the command + line option <option>-S</option>. + </para> + </listitem> + </varlistentry> + + <varlistentry> + <term><varname>SINGLESTEP</varname></term> + <listitem> + <para> + Setting this variable to <literal>on</literal> is equivalent to the command + line option <option>-s</option>. + </para> + </listitem> + </varlistentry> + + <varlistentry> + <term><varname>SQLSTATE</varname></term> + <listitem> + <para> + The error code (see <xref linkend="errcodes-appendix"/>) associated + with the last SQL query's failure, or <literal>00000</literal> if it + succeeded. + </para> + </listitem> + </varlistentry> + + <varlistentry> + <term><varname>USER</varname></term> + <listitem> + <para> + The database user you are currently connected as. This is set + every time you connect to a database (including program + start-up), but can be changed or unset. + </para> + </listitem> + </varlistentry> + + <varlistentry> + <term><varname>VERBOSITY</varname></term> + <listitem> + <para> + This variable can be set to the values <literal>default</literal>, + <literal>verbose</literal>, <literal>terse</literal>, + or <literal>sqlstate</literal> to control the verbosity of error + reports. + (See also <command>\errverbose</command>, for use when you want a verbose + version of the error you just got.) + </para> + </listitem> + </varlistentry> + + <varlistentry> + <term><varname>VERSION</varname></term> + <term><varname>VERSION_NAME</varname></term> + <term><varname>VERSION_NUM</varname></term> + <listitem> + <para> + These variables are set at program start-up to reflect + <application>psql</application>'s version, respectively as a verbose string, + a short string (e.g., <literal>9.6.2</literal>, <literal>10.1</literal>, + or <literal>11beta1</literal>), and a number (e.g., <literal>90602</literal> + or <literal>100001</literal>). They can be changed or unset. + </para> + </listitem> + </varlistentry> + + </variablelist> + + </refsect3> + + <refsect3 id="app-psql-interpolation" xreflabel="SQL Interpolation"> + <title><acronym>SQL</acronym> Interpolation</title> + + <para> + A key feature of <application>psql</application> + variables is that you can substitute (<quote>interpolate</quote>) + them into regular <acronym>SQL</acronym> statements, as well as the + arguments of meta-commands. Furthermore, + <application>psql</application> provides facilities for + ensuring that variable values used as SQL literals and identifiers are + properly quoted. The syntax for interpolating a value without + any quoting is to prepend the variable name with a colon + (<literal>:</literal>). For example, +<programlisting> +testdb=> <userinput>\set foo 'my_table'</userinput> +testdb=> <userinput>SELECT * FROM :foo;</userinput> +</programlisting> + would query the table <literal>my_table</literal>. Note that this + may be unsafe: the value of the variable is copied literally, so it can + contain unbalanced quotes, or even backslash commands. You must make sure + that it makes sense where you put it. + </para> + + <para> + When a value is to be used as an SQL literal or identifier, it is + safest to arrange for it to be quoted. To quote the value of + a variable as an SQL literal, write a colon followed by the variable + name in single quotes. To quote the value as an SQL identifier, write + a colon followed by the variable name in double quotes. + These constructs deal correctly with quotes and other special + characters embedded within the variable value. + The previous example would be more safely written this way: +<programlisting> +testdb=> <userinput>\set foo 'my_table'</userinput> +testdb=> <userinput>SELECT * FROM :"foo";</userinput> +</programlisting> + </para> + + <para> + Variable interpolation will not be performed within quoted + <acronym>SQL</acronym> literals and identifiers. Therefore, a + construction such as <literal>':foo'</literal> doesn't work to produce a quoted + literal from a variable's value (and it would be unsafe if it did work, + since it wouldn't correctly handle quotes embedded in the value). + </para> + + <para> + One example use of this mechanism is to + copy the contents of a file into a table column. + First load the file into a variable and then interpolate the variable's + value as a quoted string: +<programlisting> +testdb=> <userinput>\set content `cat my_file.txt`</userinput> +testdb=> <userinput>INSERT INTO my_table VALUES (:'content');</userinput> +</programlisting> + (Note that this still won't work if <filename>my_file.txt</filename> contains NUL bytes. + <application>psql</application> does not support embedded NUL bytes in variable values.) + </para> + + <para> + Since colons can legally appear in SQL commands, an apparent attempt + at interpolation (that is, <literal>:name</literal>, + <literal>:'name'</literal>, or <literal>:"name"</literal>) is not + replaced unless the named variable is currently set. In any case, you + can escape a colon with a backslash to protect it from substitution. + </para> + + <para> + The <literal>:{?<replaceable>name</replaceable>}</literal> special syntax returns TRUE + or FALSE depending on whether the variable exists or not, and is thus + always substituted, unless the colon is backslash-escaped. + </para> + + <para> + The colon syntax for variables is standard <acronym>SQL</acronym> for + embedded query languages, such as <application>ECPG</application>. + The colon syntaxes for array slices and type casts are + <productname>PostgreSQL</productname> extensions, which can sometimes + conflict with the standard usage. The colon-quote syntax for escaping a + variable's value as an SQL literal or identifier is a + <application>psql</application> extension. + </para> + + </refsect3> + + <refsect3 id="app-psql-prompting" xreflabel="Prompting"> + <title>Prompting</title> + + <para> + The prompts <application>psql</application> issues can be customized + to your preference. The three variables <varname>PROMPT1</varname>, + <varname>PROMPT2</varname>, and <varname>PROMPT3</varname> contain strings + and special escape sequences that describe the appearance of the + prompt. Prompt 1 is the normal prompt that is issued when + <application>psql</application> requests a new command. Prompt 2 is + issued when more input is expected during command entry, for example + because the command was not terminated with a semicolon or a quote + was not closed. + Prompt 3 is issued when you are running an <acronym>SQL</acronym> + <command>COPY FROM STDIN</command> command and you need to type in + a row value on the terminal. + </para> + + <para> + The value of the selected prompt variable is printed literally, + except where a percent sign (<literal>%</literal>) is encountered. + Depending on the next character, certain other text is substituted + instead. Defined substitutions are: + + <variablelist> + <varlistentry> + <term><literal>%M</literal></term> + <listitem> + <para> + The full host name (with domain name) of the database server, + or <literal>[local]</literal> if the connection is over a Unix + domain socket, or + <literal>[local:<replaceable>/dir/name</replaceable>]</literal>, + if the Unix domain socket is not at the compiled in default + location. + </para> + </listitem> + </varlistentry> + + <varlistentry> + <term><literal>%m</literal></term> + <listitem> + <para> + The host name of the database server, truncated at the + first dot, or <literal>[local]</literal> if the connection is + over a Unix domain socket. + </para> + </listitem> + </varlistentry> + + <varlistentry> + <term><literal>%></literal></term> + <listitem><para>The port number at which the database server is listening.</para></listitem> + </varlistentry> + + <varlistentry> + <term><literal>%n</literal></term> + <listitem> + <para> + The database session user name. (The expansion of this + value might change during a database session as the result + of the command <command>SET SESSION + AUTHORIZATION</command>.) + </para> + </listitem> + </varlistentry> + + <varlistentry> + <term><literal>%/</literal></term> + <listitem><para>The name of the current database.</para></listitem> + </varlistentry> + + <varlistentry> + <term><literal>%~</literal></term> + <listitem><para>Like <literal>%/</literal>, but the output is <literal>~</literal> + (tilde) if the database is your default database.</para></listitem> + </varlistentry> + + <varlistentry> + <term><literal>%#</literal></term> + <listitem> + <para> + If the session user is a database superuser, then a + <literal>#</literal>, otherwise a <literal>></literal>. + (The expansion of this value might change during a database + session as the result of the command <command>SET SESSION + AUTHORIZATION</command>.) + </para> + </listitem> + </varlistentry> + + <varlistentry> + <term><literal>%p</literal></term> + <listitem> + <para>The process ID of the backend currently connected to.</para> + </listitem> + </varlistentry> + + <varlistentry> + <term><literal>%R</literal></term> + <listitem> + <para> + In prompt 1 normally <literal>=</literal>, + but <literal>@</literal> if the session is in an inactive branch of a + conditional block, or <literal>^</literal> if in single-line mode, + or <literal>!</literal> if the session is disconnected from the + database (which can happen if <command>\connect</command> fails). + In prompt 2 <literal>%R</literal> is replaced by a character that + depends on why <application>psql</application> expects more input: + <literal>-</literal> if the command simply wasn't terminated yet, + but <literal>*</literal> if there is an unfinished + <literal>/* ... */</literal> comment, + a single quote if there is an unfinished quoted string, + a double quote if there is an unfinished quoted identifier, + a dollar sign if there is an unfinished dollar-quoted string, + or <literal>(</literal> if there is an unmatched left parenthesis. + In prompt 3 <literal>%R</literal> doesn't produce anything. + </para> + </listitem> + </varlistentry> + + <varlistentry> + <term><literal>%x</literal></term> + <listitem> + <para> + Transaction status: an empty string when not in a transaction + block, or <literal>*</literal> when in a transaction block, or + <literal>!</literal> when in a failed transaction block, or <literal>?</literal> + when the transaction state is indeterminate (for example, because + there is no connection). + </para> + </listitem> + </varlistentry> + + <varlistentry> + <term><literal>%l</literal></term> + <listitem> + <para> + The line number inside the current statement, starting from <literal>1</literal>. + </para> + </listitem> + </varlistentry> + + <varlistentry> + <term><literal>%</literal><replaceable class="parameter">digits</replaceable></term> + <listitem> + <para> + The character with the indicated octal code is substituted. + </para> + </listitem> + </varlistentry> + + <varlistentry> + <term><literal>%:</literal><replaceable class="parameter">name</replaceable><literal>:</literal></term> + <listitem> + <para> + The value of the <application>psql</application> variable + <replaceable class="parameter">name</replaceable>. See + <xref linkend="app-psql-variables"/>, above, for details. + </para> + </listitem> + </varlistentry> + + <varlistentry> + <term><literal>%`</literal><replaceable class="parameter">command</replaceable><literal>`</literal></term> + <listitem> + <para> + The output of <replaceable + class="parameter">command</replaceable>, similar to ordinary + <quote>back-tick</quote> substitution. + </para> + </listitem> + </varlistentry> + + <varlistentry> + <term><literal>%[</literal> ... <literal>%]</literal></term> + <listitem> + <para> + Prompts can contain terminal control characters which, for + example, change the color, background, or style of the prompt + text, or change the title of the terminal window. In order for + the line editing features of <application>Readline</application> to work properly, these + non-printing control characters must be designated as invisible + by surrounding them with <literal>%[</literal> and + <literal>%]</literal>. Multiple pairs of these can occur within + the prompt. For example: +<programlisting> +testdb=> \set PROMPT1 '%[%033[1;33;40m%]%n@%/%R%[%033[0m%]%# ' +</programlisting> + results in a boldfaced (<literal>1;</literal>) yellow-on-black + (<literal>33;40</literal>) prompt on VT100-compatible, color-capable + terminals. + </para> + </listitem> + </varlistentry> + + <varlistentry> + <term><literal>%w</literal></term> + <listitem> + <para> + Whitespace of the same width as the most recent output of + <varname>PROMPT1</varname>. This can be used as a + <varname>PROMPT2</varname> setting, so that multi-line statements are + aligned with the first line, but there is no visible secondary prompt. + </para> + </listitem> + </varlistentry> + + </variablelist> + + To insert a percent sign into your prompt, write + <literal>%%</literal>. The default prompts are + <literal>'%/%R%x%# '</literal> for prompts 1 and 2, and + <literal>'>> '</literal> for prompt 3. + </para> + + <note> + <para> + This feature was shamelessly plagiarized from + <application>tcsh</application>. + </para> + </note> + + </refsect3> + + <refsect3 id="app-psql-readline"> + <title>Command-Line Editing</title> + + <indexterm> + <primary>Readline</primary> + <secondary>in psql</secondary> + </indexterm> + <indexterm> + <primary>libedit</primary> + <secondary>in psql</secondary> + </indexterm> + + <para> + <application>psql</application> uses + the <application>Readline</application> + or <application>libedit</application> library, if available, for + convenient line editing and retrieval. The command history is + automatically saved when <application>psql</application> exits and is + reloaded when <application>psql</application> starts up. Type + up-arrow or control-P to retrieve previous lines. + </para> + + <para> + You can also use tab completion to fill in partially-typed keywords + and SQL object names in many (by no means all) contexts. For example, + at the start of a command, typing <literal>ins</literal> and pressing + TAB will fill in <literal>insert into </literal>. Then, typing a few + characters of a table or schema name and pressing <literal>TAB</literal> + will fill in the unfinished name, or offer a menu of possible completions + when there's more than one. (Depending on the library in use, you may need to + press <literal>TAB</literal> more than once to get a menu.) + </para> + + <para> + Tab completion for SQL object names requires sending queries to the + server to find possible matches. In some contexts this can interfere + with other operations. For example, after <command>BEGIN</command> + it will be too late to issue <command>SET TRANSACTION ISOLATION + LEVEL</command> if a tab-completion query is issued in between. + If you do not want tab completion at all, you + can turn it off permanently by putting this in a file named + <filename>.inputrc</filename> in your home directory: +<programlisting> +$if psql +set disable-completion on +$endif +</programlisting> + (This is not a <application>psql</application> but a + <application>Readline</application> feature. Read its documentation + for further details.) + </para> + + <para> + The <option>-n</option> (<option>--no-readline</option>) command line + option can also be useful to disable use + of <application>Readline</application> for a single run + of <application>psql</application>. This prevents tab completion, + use or recording of command line history, and editing of multi-line + commands. It is particularly useful when you need to copy-and-paste + text that contains <literal>TAB</literal> characters. + </para> + </refsect3> + </refsect2> + </refsect1> + + + <refsect1 id="app-psql-environment" xreflabel="Environment"> + <title>Environment</title> + + <variablelist> + + <varlistentry> + <term><envar>COLUMNS</envar></term> + + <listitem> + <para> + If <literal>\pset columns</literal> is zero, controls the + width for the <literal>wrapped</literal> format and width for determining + if wide output requires the pager or should be switched to the + vertical format in expanded auto mode. + </para> + </listitem> + </varlistentry> + + <varlistentry> + <term><envar>PGDATABASE</envar></term> + <term><envar>PGHOST</envar></term> + <term><envar>PGPORT</envar></term> + <term><envar>PGUSER</envar></term> + + <listitem> + <para> + Default connection parameters (see <xref linkend="libpq-envars"/>). + </para> + </listitem> + </varlistentry> + + <varlistentry> + <term><envar>PG_COLOR</envar></term> + <listitem> + <para> + Specifies whether to use color in diagnostic messages. Possible values + are <literal>always</literal>, <literal>auto</literal> and + <literal>never</literal>. + </para> + </listitem> + </varlistentry> + + <varlistentry> + <term><envar>PSQL_EDITOR</envar></term> + <term><envar>EDITOR</envar></term> + <term><envar>VISUAL</envar></term> + + <listitem> + <para> + Editor used by the <command>\e</command>, <command>\ef</command>, + and <command>\ev</command> commands. + These variables are examined in the order listed; + the first that is set is used. + If none of them is set, the default is to use <filename>vi</filename> + on Unix systems or <filename>notepad.exe</filename> on Windows systems. + </para> + </listitem> + </varlistentry> + + <varlistentry> + <term><envar>PSQL_EDITOR_LINENUMBER_ARG</envar></term> + + <listitem> + <para> + When <command>\e</command>, <command>\ef</command>, or + <command>\ev</command> is used + with a line number argument, this variable specifies the + command-line argument used to pass the starting line number to + the user's editor. For editors such as <productname>Emacs</productname> or + <productname>vi</productname>, this is a plus sign. Include a trailing + space in the value of the variable if there needs to be space + between the option name and the line number. Examples: +<programlisting> +PSQL_EDITOR_LINENUMBER_ARG='+' +PSQL_EDITOR_LINENUMBER_ARG='--line ' +</programlisting> + </para> + + <para> + The default is <literal>+</literal> on Unix systems + (corresponding to the default editor <filename>vi</filename>, + and useful for many other common editors); but there is no + default on Windows systems. + </para> + </listitem> + </varlistentry> + + <varlistentry> + <term><envar>PSQL_HISTORY</envar></term> + + <listitem> + <para> + Alternative location for the command history file. Tilde (<literal>~</literal>) expansion is performed. + </para> + </listitem> + </varlistentry> + + <varlistentry> + <term><envar>PSQL_PAGER</envar></term> + <term><envar>PAGER</envar></term> + + <listitem> + <para> + If a query's results do not fit on the screen, they are piped + through this command. Typical values are <literal>more</literal> + or <literal>less</literal>. + Use of the pager can be disabled by setting <envar>PSQL_PAGER</envar> + or <envar>PAGER</envar> to an empty string, or by adjusting the + pager-related options of the <command>\pset</command> command. + These variables are examined in the order listed; + the first that is set is used. + If neither of them is set, the default is to use <literal>more</literal> on most + platforms, but <literal>less</literal> on Cygwin. + </para> + + </listitem> + </varlistentry> + + <varlistentry> + <term><envar>PSQL_WATCH_PAGER</envar></term> + + <listitem> + <para> + When a query is executed repeatedly with the <command>\watch</command> + command, a pager is not used by default. This behavior can be changed + by setting <envar>PSQL_WATCH_PAGER</envar> to a pager command, on Unix + systems. The <literal>pspg</literal> pager (not part of + <productname>PostgreSQL</productname> but available in many open source + software distributions) can display the output of + <command>\watch</command> if started with the option + <literal>--stream</literal>. + </para> + + </listitem> + </varlistentry> + + <varlistentry> + <term><envar>PSQLRC</envar></term> + + <listitem> + <para> + Alternative location of the user's <filename>.psqlrc</filename> file. Tilde (<literal>~</literal>) expansion is performed. + </para> + </listitem> + </varlistentry> + + <varlistentry> + <term><envar>SHELL</envar></term> + + <listitem> + <para> + Command executed by the <command>\!</command> command. + </para> + </listitem> + </varlistentry> + + <varlistentry> + <term><envar>TMPDIR</envar></term> + + <listitem> + <para> + Directory for storing temporary files. The default is + <filename>/tmp</filename>. + </para> + </listitem> + </varlistentry> + </variablelist> + + <para> + This utility, like most other <productname>PostgreSQL</productname> utilities, + also uses the environment variables supported by <application>libpq</application> + (see <xref linkend="libpq-envars"/>). + </para> + + </refsect1> + + + <refsect1> + <title>Files</title> + + <variablelist> + <varlistentry> + <term><filename>psqlrc</filename> and <filename>~/.psqlrc</filename></term> + <listitem> + <para> + Unless it is passed an <option>-X</option> option, + <application>psql</application> attempts to read and execute commands + from the system-wide startup file (<filename>psqlrc</filename>) and then + the user's personal startup file (<filename>~/.psqlrc</filename>), after + connecting to the database but before accepting normal commands. + These files can be used to set up the client and/or the server to taste, + typically with <command>\set</command> and <command>SET</command> + commands. + </para> + <para> + The system-wide startup file is named <filename>psqlrc</filename>. + By default it is + sought in the installation's <quote>system configuration</quote> directory, + which is most reliably identified by running <literal>pg_config + --sysconfdir</literal>. + Typically this directory will be <filename>../etc/</filename> + relative to the directory containing + the <productname>PostgreSQL</productname> executables. + The directory to look in can be set explicitly via + the <envar>PGSYSCONFDIR</envar> environment variable. + </para> + <para> + The user's personal startup file is named <filename>.psqlrc</filename> + and is sought in the invoking user's home directory. + On Windows the personal startup file is instead named + <filename>%APPDATA%\postgresql\psqlrc.conf</filename>. + In either case, this default file path can be overridden by setting + the <envar>PSQLRC</envar> environment variable. + </para> + <para> + Both the system-wide startup file and the user's personal startup file + can be made <application>psql</application>-version-specific + by appending a dash and the <productname>PostgreSQL</productname> + major or minor release identifier to the file name, + for example <filename>~/.psqlrc-&majorversion;</filename> or + <filename>~/.psqlrc-&version;</filename>. + The most specific version-matching file will be read in preference + to a non-version-specific file. + These version suffixes are added after determining the file path + as explained above. + </para> + </listitem> + </varlistentry> + + <varlistentry> + <term><filename>.psql_history</filename></term> + <listitem> + <para> + The command-line history is stored in the file + <filename>~/.psql_history</filename>, or + <filename>%APPDATA%\postgresql\psql_history</filename> on Windows. + </para> + <para> + The location of the history file can be set explicitly via + the <varname>HISTFILE</varname> <application>psql</application> variable or + the <envar>PSQL_HISTORY</envar> environment variable. + </para> + </listitem> + </varlistentry> + </variablelist> + </refsect1> + + + <refsect1> + <title>Notes</title> + + <itemizedlist> + <listitem> + <para><application>psql</application> works best with servers of the same + or an older major version. Backslash commands are particularly likely + to fail if the server is of a newer version than <application>psql</application> + itself. However, backslash commands of the <literal>\d</literal> family should + work with servers of versions back to 9.2, though not necessarily with + servers newer than <application>psql</application> itself. The general + functionality of running SQL commands and displaying query results + should also work with servers of a newer major version, but this cannot + be guaranteed in all cases. + </para> + <para> + If you want to use <application>psql</application> to connect to several + servers of different major versions, it is recommended that you use the + newest version of <application>psql</application>. Alternatively, you + can keep around a copy of <application>psql</application> from each + major version and be sure to use the version that matches the + respective server. But in practice, this additional complication should + not be necessary. + </para> + </listitem> + + <listitem> + <para> + Before <productname>PostgreSQL</productname> 9.6, + the <option>-c</option> option implied <option>-X</option> + (<option>--no-psqlrc</option>); this is no longer the case. + </para> + </listitem> + + <listitem> + <para> + Before <productname>PostgreSQL</productname> 8.4, + <application>psql</application> allowed the + first argument of a single-letter backslash command to start + directly after the command, without intervening whitespace. + Now, some whitespace is required. + </para> + </listitem> + </itemizedlist> + </refsect1> + + + <refsect1> + <title>Notes for Windows Users</title> + + <para> + <application>psql</application> is built as a <quote>console + application</quote>. Since the Windows console windows use a different + encoding than the rest of the system, you must take special care + when using 8-bit characters within <application>psql</application>. + If <application>psql</application> detects a problematic + console code page, it will warn you at startup. To change the + console code page, two things are necessary: + + <itemizedlist> + <listitem> + <para> + Set the code page by entering <userinput>cmd.exe /c chcp + 1252</userinput>. (1252 is a code page that is appropriate for + German; replace it with your value.) If you are using Cygwin, + you can put this command in <filename>/etc/profile</filename>. + </para> + </listitem> + + <listitem> + <para> + Set the console font to <literal>Lucida Console</literal>, because the + raster font does not work with the ANSI code page. + </para> + </listitem> + </itemizedlist></para> + + </refsect1> + + + <refsect1 id="app-psql-examples" xreflabel="Examples"> + <title>Examples</title> + + <para> + The first example shows how to spread a command over several lines of + input. Notice the changing prompt: +<programlisting> +testdb=> <userinput>CREATE TABLE my_table (</userinput> +testdb(> <userinput> first integer not null default 0,</userinput> +testdb(> <userinput> second text)</userinput> +testdb-> <userinput>;</userinput> +CREATE TABLE +</programlisting> + Now look at the table definition again: +<programlisting> +testdb=> <userinput>\d my_table</userinput> + Table "public.my_table" + Column | Type | Collation | Nullable | Default +--------+---------+-----------+----------+--------- + first | integer | | not null | 0 + second | text | | | +</programlisting> + Now we change the prompt to something more interesting: +<programlisting> +testdb=> <userinput>\set PROMPT1 '%n@%m %~%R%# '</userinput> +peter@localhost testdb=> +</programlisting> + Let's assume you have filled the table with data and want to take a + look at it: +<programlisting> +peter@localhost testdb=> SELECT * FROM my_table; + first | second +-------+-------- + 1 | one + 2 | two + 3 | three + 4 | four +(4 rows) +</programlisting> + You can display tables in different ways by using the + <command>\pset</command> command: +<programlisting> +peter@localhost testdb=> <userinput>\pset border 2</userinput> +Border style is 2. +peter@localhost testdb=> <userinput>SELECT * FROM my_table;</userinput> ++-------+--------+ +| first | second | ++-------+--------+ +| 1 | one | +| 2 | two | +| 3 | three | +| 4 | four | ++-------+--------+ +(4 rows) + +peter@localhost testdb=> <userinput>\pset border 0</userinput> +Border style is 0. +peter@localhost testdb=> <userinput>SELECT * FROM my_table;</userinput> +first second +----- ------ + 1 one + 2 two + 3 three + 4 four +(4 rows) + +peter@localhost testdb=> <userinput>\pset border 1</userinput> +Border style is 1. +peter@localhost testdb=> <userinput>\pset format csv</userinput> +Output format is csv. +peter@localhost testdb=> <userinput>\pset tuples_only</userinput> +Tuples only is on. +peter@localhost testdb=> <userinput>SELECT second, first FROM my_table;</userinput> +one,1 +two,2 +three,3 +four,4 +peter@localhost testdb=> <userinput>\pset format unaligned</userinput> +Output format is unaligned. +peter@localhost testdb=> <userinput>\pset fieldsep '\t'</userinput> +Field separator is " ". +peter@localhost testdb=> <userinput>SELECT second, first FROM my_table;</userinput> +one 1 +two 2 +three 3 +four 4 +</programlisting> + Alternatively, use the short commands: +<programlisting> +peter@localhost testdb=> <userinput>\a \t \x</userinput> +Output format is aligned. +Tuples only is off. +Expanded display is on. +peter@localhost testdb=> <userinput>SELECT * FROM my_table;</userinput> +-[ RECORD 1 ]- +first | 1 +second | one +-[ RECORD 2 ]- +first | 2 +second | two +-[ RECORD 3 ]- +first | 3 +second | three +-[ RECORD 4 ]- +first | 4 +second | four +</programlisting> + </para> + + <para> + Also, these output format options can be set for just one query by using + <literal>\g</literal>: +<programlisting> +peter@localhost testdb=> <userinput>SELECT * FROM my_table</userinput> +peter@localhost testdb-> <userinput>\g (format=aligned tuples_only=off expanded=on)</userinput> +-[ RECORD 1 ]- +first | 1 +second | one +-[ RECORD 2 ]- +first | 2 +second | two +-[ RECORD 3 ]- +first | 3 +second | three +-[ RECORD 4 ]- +first | 4 +second | four +</programlisting> + </para> + + <para> + Here is an example of using the <command>\df</command> command to + find only functions with names matching <literal>int*pl</literal> + and whose second argument is of type <type>bigint</type>: +<programlisting> +testdb=> <userinput>\df int*pl * bigint</userinput> + List of functions + Schema | Name | Result data type | Argument data types | Type +------------+---------+------------------+---------------------+------ + pg_catalog | int28pl | bigint | smallint, bigint | func + pg_catalog | int48pl | bigint | integer, bigint | func + pg_catalog | int8pl | bigint | bigint, bigint | func +(3 rows) +</programlisting> + </para> + + <para> + When suitable, query results can be shown in a crosstab representation + with the <command>\crosstabview</command> command: +<programlisting> +testdb=> <userinput>SELECT first, second, first > 2 AS gt2 FROM my_table;</userinput> + first | second | gt2 +-------+--------+----- + 1 | one | f + 2 | two | f + 3 | three | t + 4 | four | t +(4 rows) + +testdb=> <userinput>\crosstabview first second</userinput> + first | one | two | three | four +-------+-----+-----+-------+------ + 1 | f | | | + 2 | | f | | + 3 | | | t | + 4 | | | | t +(4 rows) +</programlisting> + +This second example shows a multiplication table with rows sorted in reverse +numerical order and columns with an independent, ascending numerical order. +<programlisting> +testdb=> <userinput>SELECT t1.first as "A", t2.first+100 AS "B", t1.first*(t2.first+100) as "AxB",</userinput> +testdb(> <userinput>row_number() over(order by t2.first) AS ord</userinput> +testdb(> <userinput>FROM my_table t1 CROSS JOIN my_table t2 ORDER BY 1 DESC</userinput> +testdb(> <userinput>\crosstabview "A" "B" "AxB" ord</userinput> + A | 101 | 102 | 103 | 104 +---+-----+-----+-----+----- + 4 | 404 | 408 | 412 | 416 + 3 | 303 | 306 | 309 | 312 + 2 | 202 | 204 | 206 | 208 + 1 | 101 | 102 | 103 | 104 +(4 rows) +</programlisting></para> + + </refsect1> + +</refentry> |