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+@ignore
+This file documents the user interface to the GNU History library.
+
+Copyright (C) 1988--2020 Free Software Foundation, Inc.
+Authored by Brian Fox and Chet Ramey.
+
+Permission is granted to make and distribute verbatim copies of this manual
+provided the copyright notice and this permission notice are preserved on
+all copies.
+
+Permission is granted to process this file through Tex and print the
+results, provided the printed document carries copying permission notice
+identical to this one except for the removal of this paragraph (this
+paragraph not being relevant to the printed manual).
+
+Permission is granted to copy and distribute modified versions of this
+manual under the conditions for verbatim copying, provided also that the
+GNU Copyright statement is available to the distributee, and provided that
+the entire resulting derived work is distributed under the terms of a
+permission notice identical to this one.
+
+Permission is granted to copy and distribute translations of this manual
+into another language, under the above conditions for modified versions.
+@end ignore
+
+@node Using History Interactively
+@chapter Using History Interactively
+
+@ifclear BashFeatures
+@defcodeindex bt
+@end ifclear
+
+@ifset BashFeatures
+This chapter describes how to use the @sc{gnu} History Library
+interactively, from a user's standpoint.
+It should be considered a user's guide.
+For information on using the @sc{gnu} History Library in other programs,
+see the @sc{gnu} Readline Library Manual.
+@end ifset
+@ifclear BashFeatures
+This chapter describes how to use the @sc{gnu} History Library interactively,
+from a user's standpoint.  It should be considered a user's guide.  For
+information on using the @sc{gnu} History Library in your own programs,
+@pxref{Programming with GNU History}.
+@end ifclear
+
+@ifset BashFeatures
+@menu
+* Bash History Facilities::	How Bash lets you manipulate your command
+				history.
+* Bash History Builtins::	The Bash builtin commands that manipulate
+				the command history.
+* History Interaction::		What it feels like using History as a user.
+@end menu
+@end ifset
+@ifclear BashFeatures
+@menu
+* History Interaction::		What it feels like using History as a user.
+@end menu
+@end ifclear
+
+@ifset BashFeatures
+@node Bash History Facilities
+@section Bash History Facilities
+@cindex command history
+@cindex history list
+
+When the @option{-o history} option to the @code{set} builtin
+is enabled (@pxref{The Set Builtin}),
+the shell provides access to the @dfn{command history},
+the list of commands previously typed.
+The value of the @env{HISTSIZE} shell variable is used as the
+number of commands to save in a history list.
+The text of the last @env{$HISTSIZE}
+commands (default 500) is saved.
+The shell stores each command in the history list prior to
+parameter and variable expansion
+but after history expansion is performed, subject to the
+values of the shell variables
+@env{HISTIGNORE} and @env{HISTCONTROL}.
+
+When the shell starts up, the history is initialized from the
+file named by the @env{HISTFILE} variable (default @file{~/.bash_history}).
+The file named by the value of @env{HISTFILE} is truncated, if
+necessary, to contain no more than the number of lines specified by
+the value of the @env{HISTFILESIZE} variable.
+When a shell with history enabled exits, the last
+@env{$HISTSIZE} lines are copied from the history list to the file
+named by @env{$HISTFILE}.
+If the @code{histappend} shell option is set (@pxref{Bash Builtins}),
+the lines are appended to the history file,
+otherwise the history file is overwritten.
+If @env{HISTFILE}
+is unset, or if the history file is unwritable, the history is not saved.
+After saving the history, the history file is truncated
+to contain no more than @env{$HISTFILESIZE} lines.
+If @env{HISTFILESIZE} is unset, or set to null, a non-numeric value, or
+a numeric value less than zero, the history file is not truncated.
+
+If the @env{HISTTIMEFORMAT} is set, the time stamp information
+associated with each history entry is written to the history file,
+marked with the history comment character.
+When the history file is read, lines beginning with the history
+comment character followed immediately by a digit are interpreted
+as timestamps for the following history entry.
+
+The builtin command @code{fc} may be used to list or edit and re-execute
+a portion of the history list.
+The @code{history} builtin may be used to display or modify the history
+list and manipulate the history file.
+When using command-line editing, search commands
+are available in each editing mode that provide access to the
+history list (@pxref{Commands For History}).
+
+The shell allows control over which commands are saved on the history
+list.  The @env{HISTCONTROL} and @env{HISTIGNORE}
+variables may be set to cause the shell to save only a subset of the
+commands entered.
+The @code{cmdhist}
+shell option, if enabled, causes the shell to attempt to save each
+line of a multi-line command in the same history entry, adding
+semicolons where necessary to preserve syntactic correctness.
+The @code{lithist}
+shell option causes the shell to save the command with embedded newlines
+instead of semicolons.
+The @code{shopt} builtin is used to set these options.
+@xref{The Shopt Builtin}, for a description of @code{shopt}.
+
+@node Bash History Builtins
+@section Bash History Builtins
+@cindex history builtins
+
+Bash provides two builtin commands which manipulate the
+history list and history file.
+
+@table @code
+
+@item fc
+@btindex fc
+@example
+@code{fc [-e @var{ename}] [-lnr] [@var{first}] [@var{last}]}
+@code{fc -s [@var{pat}=@var{rep}] [@var{command}]}
+@end example
+
+The first form selects a range of commands from @var{first} to
+@var{last} from the history list and displays or edits and re-executes
+them.
+Both @var{first} and
+@var{last} may be specified as a string (to locate the most recent
+command beginning with that string) or as a number (an index into the
+history list, where a negative number is used as an offset from the
+current command number).
+
+When listing, a @var{first} or @var{last} of 0 is equivalent to -1
+and -0 is equivalent to the current command (usually the @code{fc}
+command);
+otherwise 0 is equivalent to -1 and -0 is invalid.
+
+If @var{last} is not specified, it is set to
+@var{first}.  If @var{first} is not specified, it is set to the previous
+command for editing and @minus{}16 for listing.  If the @option{-l} flag is
+given, the commands are listed on standard output.  The @option{-n} flag
+suppresses the command numbers when listing.  The @option{-r} flag
+reverses the order of the listing.  Otherwise, the editor given by
+@var{ename} is invoked on a file containing those commands.  If
+@var{ename} is not given, the value of the following variable expansion
+is used: @code{$@{FCEDIT:-$@{EDITOR:-vi@}@}}.  This says to use the
+value of the @env{FCEDIT} variable if set, or the value of the
+@env{EDITOR} variable if that is set, or @code{vi} if neither is set.
+When editing is complete, the edited commands are echoed and executed.
+
+In the second form, @var{command} is re-executed after each instance
+of @var{pat} in the selected command is replaced by @var{rep}.
+@var{command} is interpreted the same as @var{first} above.
+
+A useful alias to use with the @code{fc} command is @code{r='fc -s'}, so
+that typing @samp{r cc} runs the last command beginning with @code{cc}
+and typing @samp{r} re-executes the last command (@pxref{Aliases}).
+
+@item history
+@btindex history
+@example
+history [@var{n}]
+history -c
+history -d @var{offset}
+history -d @var{start}-@var{end}
+history [-anrw] [@var{filename}]
+history -ps @var{arg}
+@end example
+
+With no options, display the history list with line numbers.
+Lines prefixed with a @samp{*} have been modified.
+An argument of @var{n} lists only the last @var{n} lines.
+If the shell variable @env{HISTTIMEFORMAT} is set and not null,
+it is used as a format string for @var{strftime} to display
+the time stamp associated with each displayed history entry.
+No intervening blank is printed between the formatted time stamp
+and the history line.
+
+Options, if supplied, have the following meanings:
+
+@table @code
+@item -c
+Clear the history list.  This may be combined
+with the other options to replace the history list completely.
+
+@item -d @var{offset}
+Delete the history entry at position @var{offset}.
+If @var{offset} is positive, it should be specified as it appears when
+the history is displayed.
+If @var{offset} is negative, it is interpreted as relative to one greater
+than the last history position, so negative indices count back from the
+end of the history, and an index of @samp{-1} refers to the current
+@code{history -d} command.
+
+@item -d @var{start}-@var{end}
+Delete the history entries between positions @var{start} and @var{end},
+inclusive.  Positive and negative values for @var{start} and @var{end}
+are interpreted as described above.
+
+@item -a
+Append the new history lines to the history file.
+These are history lines entered since the beginning of the current
+Bash session, but not already appended to the history file.
+
+@item -n
+Append the history lines not already read from the history file
+to the current history list.  These are lines appended to the history
+file since the beginning of the current Bash session.
+
+@item -r
+Read the history file and append its contents to
+the history list.
+
+@item -w
+Write out the current history list to the history file.
+
+@item -p
+Perform history substitution on the @var{arg}s and display the result
+on the standard output, without storing the results in the history list.
+
+@item -s
+The @var{arg}s are added to the end of
+the history list as a single entry.
+
+@end table
+
+When any of the @option{-w}, @option{-r}, @option{-a}, or @option{-n} options is
+used, if @var{filename}
+is given, then it is used as the history file.  If not, then
+the value of the @env{HISTFILE} variable is used.
+
+@end table
+@end ifset
+
+@node History Interaction
+@section History Expansion
+@cindex history expansion
+
+The History library provides a history expansion feature that is similar
+to the history expansion provided by @code{csh}.  This section
+describes the syntax used to manipulate the history information.
+
+History expansions introduce words from the history list into
+the input stream, making it easy to repeat commands, insert the
+arguments to a previous command into the current input line, or
+fix errors in previous commands quickly.
+
+@ifset BashFeatures
+History expansion is performed immediately after a complete line
+is read, before the shell breaks it into words, and is performed
+on each line individually.  Bash attempts to inform the history
+expansion functions about quoting still in effect from previous lines.
+@end ifset
+
+History expansion takes place in two parts.  The first is to determine
+which line from the history list should be used during substitution.
+The second is to select portions of that line for inclusion into the
+current one.  The line selected from the history is called the
+@dfn{event}, and the portions of that line that are acted upon are
+called @dfn{words}.  Various @dfn{modifiers} are available to manipulate
+the selected words.  The line is broken into words in the same fashion
+that Bash does, so that several words
+surrounded by quotes are considered one word.
+History expansions are introduced by the appearance of the
+history expansion character, which is @samp{!} by default.
+
+History expansion implements shell-like quoting conventions:
+a backslash can be used to remove the special handling for the next character;
+single quotes enclose verbatim sequences of characters, and can be used to
+inhibit history expansion;
+and characters enclosed within double quotes may be subject to history
+expansion, since backslash can escape the history expansion character,
+but single quotes may not, since they are not treated specially within
+double quotes.
+
+@ifset BashFeatures
+When using the shell, only @samp{\} and @samp{'} may be used to escape the
+history expansion character, but the history expansion character is
+also treated as quoted if it immediately precedes the closing double quote
+in a double-quoted string. 
+@end ifset
+
+@ifset BashFeatures
+Several shell options settable with the @code{shopt}
+builtin (@pxref{The Shopt Builtin}) may be used to tailor
+the behavior of history expansion.  If the
+@code{histverify} shell option is enabled, and Readline
+is being used, history substitutions are not immediately passed to
+the shell parser.
+Instead, the expanded line is reloaded into the Readline
+editing buffer for further modification.
+If Readline is being used, and the @code{histreedit}
+shell option is enabled, a failed history expansion will be
+reloaded into the Readline editing buffer for correction.
+The @option{-p} option to the @code{history} builtin command
+may be used to see what a history expansion will do before using it.
+The @option{-s} option to the @code{history} builtin may be used to
+add commands to the end of the history list without actually executing
+them, so that they are available for subsequent recall.
+This is most useful in conjunction with Readline.
+
+The shell allows control of the various characters used by the
+history expansion mechanism with the @code{histchars} variable,
+as explained above (@pxref{Bash Variables}).  The shell uses
+the history comment character to mark history timestamps when
+writing the history file.
+@end ifset
+
+@menu
+* Event Designators::	How to specify which history line to use.
+* Word Designators::	Specifying which words are of interest.
+* Modifiers::		Modifying the results of substitution.
+@end menu
+
+@node Event Designators
+@subsection Event Designators
+@cindex event designators
+
+An event designator is a reference to a command line entry in the
+history list.
+Unless the reference is absolute, events are relative to the current
+position in the history list.
+@cindex history events
+
+@table @asis
+
+@item @code{!}
+@ifset BashFeatures
+Start a history substitution, except when followed by a space, tab,
+the end of the line, @samp{=} or @samp{(} (when the
+@code{extglob} shell option is enabled using the @code{shopt} builtin).
+@end ifset
+@ifclear BashFeatures
+Start a history substitution, except when followed by a space, tab,
+the end of the line, or @samp{=}.
+@end ifclear
+
+@item @code{!@var{n}}
+Refer to command line @var{n}.
+
+@item @code{!-@var{n}}
+Refer to the command @var{n} lines back.
+
+@item @code{!!}
+Refer to the previous command.  This is a synonym for @samp{!-1}.
+
+@item @code{!@var{string}}
+Refer to the most recent command
+preceding the current position in the history list
+starting with @var{string}.
+
+@item @code{!?@var{string}[?]}
+Refer to the most recent command
+preceding the current position in the history list
+containing @var{string}.
+The trailing
+@samp{?} may be omitted if the @var{string} is followed immediately by
+a newline.
+If @var{string} is missing, the string from the most recent search is used;
+it is an error if there is no previous search string.
+
+@item @code{^@var{string1}^@var{string2}^}
+Quick Substitution.  Repeat the last command, replacing @var{string1}
+with @var{string2}.  Equivalent to
+@code{!!:s^@var{string1}^@var{string2}^}.
+
+@item @code{!#}
+The entire command line typed so far.
+
+@end table
+
+@node Word Designators
+@subsection Word Designators
+
+Word designators are used to select desired words from the event.
+A @samp{:} separates the event specification from the word designator.  It
+may be omitted if the word designator begins with a @samp{^}, @samp{$},
+@samp{*}, @samp{-}, or @samp{%}.  Words are numbered from the beginning
+of the line, with the first word being denoted by 0 (zero).  Words are
+inserted into the current line separated by single spaces.
+
+@need 0.75
+For example,
+
+@table @code
+@item !!
+designates the preceding command.  When you type this, the preceding
+command is repeated in toto.
+
+@item !!:$
+designates the last argument of the preceding command.  This may be
+shortened to @code{!$}.
+
+@item !fi:2
+designates the second argument of the most recent command starting with
+the letters @code{fi}.
+@end table
+
+@need 0.75
+Here are the word designators:
+ 
+@table @code
+
+@item 0 (zero)
+The @code{0}th word.  For many applications, this is the command word.
+
+@item @var{n}
+The @var{n}th word.
+
+@item ^
+The first argument; that is, word 1.
+
+@item $
+The last argument.
+
+@item %
+The first word matched by the most recent @samp{?@var{string}?} search,
+if the search string begins with a character that is part of a word.
+
+@item @var{x}-@var{y}
+A range of words; @samp{-@var{y}} abbreviates @samp{0-@var{y}}.
+
+@item *
+All of the words, except the @code{0}th.  This is a synonym for @samp{1-$}.
+It is not an error to use @samp{*} if there is just one word in the event;
+the empty string is returned in that case.
+
+@item @var{x}*
+Abbreviates @samp{@var{x}-$}
+
+@item @var{x}-
+Abbreviates @samp{@var{x}-$} like @samp{@var{x}*}, but omits the last word.
+If @samp{x} is missing, it defaults to 0.
+
+@end table
+
+If a word designator is supplied without an event specification, the
+previous command is used as the event.
+
+@node Modifiers
+@subsection Modifiers
+
+After the optional word designator, you can add a sequence of one or more
+of the following modifiers, each preceded by a @samp{:}.
+These modify, or edit, the word or words selected from the history event.
+
+@table @code
+
+@item h
+Remove a trailing pathname component, leaving only the head.
+
+@item t
+Remove all leading pathname components, leaving the tail.
+
+@item r
+Remove a trailing suffix of the form @samp{.@var{suffix}}, leaving
+the basename.
+
+@item e
+Remove all but the trailing suffix.
+
+@item p
+Print the new command but do not execute it.
+
+@ifset BashFeatures
+@item q
+Quote the substituted words, escaping further substitutions.
+
+@item x
+Quote the substituted words as with @samp{q},
+but break into words at spaces, tabs, and newlines.
+The @samp{q} and @samp{x} modifiers are mutually exclusive; the last one
+supplied is used.
+@end ifset
+
+@item s/@var{old}/@var{new}/
+Substitute @var{new} for the first occurrence of @var{old} in the
+event line.
+Any character may be used as the delimiter in place of @samp{/}.
+The delimiter may be quoted in @var{old} and @var{new}
+with a single backslash.  If @samp{&} appears in @var{new},
+it is replaced by @var{old}.  A single backslash will quote
+the @samp{&}.
+If @var{old} is null, it is set to the last @var{old}
+substituted, or, if no previous history substitutions took place,
+the last @var{string}
+in a !?@var{string}@code{[?]}
+search.
+If @var{new} is is null, each matching @var{old} is deleted.
+The final delimiter is optional if it is the last
+character on the input line.
+
+@item &
+Repeat the previous substitution.
+
+@item g
+@itemx a
+Cause changes to be applied over the entire event line.  Used in
+conjunction with @samp{s}, as in @code{gs/@var{old}/@var{new}/},
+or with @samp{&}.
+
+@item G
+Apply the following @samp{s} or @samp{&} modifier once to each word
+in the event.
+
+@end table