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<!-- $LynxId: environments.html,v 1.22 2021/07/01 21:02:38 tom Exp $ -->
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01//EN">
<html>
<head>
<meta name="generator" content=
"HTML Tidy for HTML5 for Linux version 5.6.0">
<title>Help on Lynx's Environment variables</title>
<link rev="made" href="mailto:lynx-dev@nongnu.org">
<meta http-equiv="Content-Type" content=
"text/html; charset=us-ascii">
<meta name="description" content=
"Describes environment variables used by Lynx. Some are specific to Lynx, others are common with similar programs.">
</head>
<body>
<div class="nav">
<ul>
<li><a href="#overview">Environment Variables</a></li>
<li><a href="#env">Variables Used By Lynx</a></li>
<li><a href="#setenv">Variables Set or Modified By Lynx</a></li>
<li><a href="#cgi">Simulated CGI Support</a></li>
<li><a href="#language">Native Language Support</a></li>
<li><a href="#proxy">Proxy details and examples</a></li>
<li><a href="#dos">Win32 (95/NT) and 386 DOS</a></li>
</ul>
</div>
<h2><a name="overview" id="overview">Environment Variables</a></h2>
<pre>
In addition to various “standard” environment variables
such as HOME, PATH, USER, DISPLAY, TMPDIR, etc, <strong>Lynx</strong> utilizes
several <strong>Lynx</strong>-specific environment variables, <a href="#env">if they exist</a>.
Others may be created or modified by <strong>Lynx</strong> to pass data to
an external program, or for other reasons. These are
listed separately <a href="#setenv">below</a>.
See also the sections on <a href=
"#cgi">Simulated CGI Support</a> and
<a href="#language">Native Language Support</a>, below.
Note: Not all environment variables apply to all types of
platforms supported by <strong>Lynx</strong>, though most do. Feedback on
platform dependencies is solicited. See also <a href=
"#dos">win32/dos</a> specific
variables.
</pre>
<h2><a name="env" id="env">Variables Used By Lynx</a></h2>
<pre>
COLORTERM
If set, color capability for the terminal
is forced on at startup time. The actual
value assigned to the variable is ignored.
This variable is only meaningful if <strong>Lynx</strong>
was built using the slang screen-handling
library.
LYNX_CFG
This variable, if set, will override
the default location and name of the
global configuration file (normally,
lynx.cfg) that was defined by the
LYNX_CFG_FILE constant in the
userdefs.h file, during installation.
See the userdefs.h file for more
information.
LYNX_HELPFILE
If set, this variable overrides the
compiled-in URL and configuration file
URL for the <strong>Lynx</strong> help file.
LYNX_LOCALEDIR
If set, this variable overrides the
compiled-in location of the locale
directory which contains native lan-
guage (NLS) message text.
LYNX_LSS
This variable, if set, specifies the
location of the default <strong>Lynx</strong> character
style sheet file. [Currently only
meaningful if <strong>Lynx</strong> was built using
experimental color style support.]
LYNX_SAVE_SPACE
This variable, if set, will override
the default path prefix for files
saved to disk that is defined in the
lynx.cfg SAVE_SPACE: statement. See
the lynx.cfg file for more information.
LYNX_TEMP_SPACE
This variable, if set, will override
the default path prefix for temporary
files that was defined during installation,
as well as any value that may
be assigned to the TMPDIR variable.
LYNX_TRACE
If set, causes <strong>Lynx</strong> to write a trace
file as if the -trace option were sup-
plied.
LYNX_TRACE_FILE
If set, overrides the compiled-in name
of the trace file, which is either
Lynx.trace or LY-TRACE.LOG (the latter
on the DOS platform). The trace file
is in either case relative to the home
directory.
MAIL
This variable specifies the default
inbox <strong>Lynx</strong> will check for new mail, if
such checking is enabled in the
lynx.cfg file.
NEWS_ORGANIZATION
This variable, if set, provides the
string used in the Organization:
header of USENET news postings. It will
override the setting of the ORGANIZATION
environment variable, if it is also set
(and, on UNIX, the contents of an
/etc/organization file, if present).
NNTPSERVER
If set, this variable specifies the
default NNTP server that will be used
for USENET news reading and posting
with <strong>Lynx</strong>, via news: URL's.
ORGANIZATION
This variable, if set, provides the
string used in the Organization:
header of USENET news postings. On
UNIX, it will override the contents of
an /etc/organization file, if present.
<em>PROTOCOL</em>_proxy
<strong>Lynx</strong> supports the use of proxy servers
that can act as firewall gateways and
caching servers. They are preferable
to the older gateway servers (see
WWW_access_GATEWAY, below).
Each protocol used by <strong>Lynx</strong> (http, ftp,
gopher, etc), can be mapped separately
by setting environment variables of
the form <em>PROTOCOL</em>_proxy (literally:
http_proxy, ftp_proxy, gopher_proxy,
etc), to “http://some.server.dom:port/”.
See <a href=
"#proxy">Proxy details and examples</a>.
WWW_<em>access</em>_GATEWAY
<strong>Lynx</strong> still supports use of gateway
servers, with the servers specified
via “WWW_<em>access</em>_GATEWAY” variables
(where “access” is lower case and can
be “http”, “ftp”, “gopher” or “wais”),
however most gateway servers have been
discontinued. Note that you do not
include a terminal “/” for gateways,
but do for proxies specified by <em>PROTOCOL</em>_proxy
environment variables. See <a href=
"#proxy">Proxy details</a>.
WWW_HOME
This variable, if set, will override
the default startup URL specified in
any of the <strong>Lynx</strong> configuration files.
</pre>
<h2><a name="setenv" id="setenv">Variables Set or Modified By
Lynx</a></h2>
<pre>
LYNX_PRINT_DATE This variable is set by the <strong>Lynx</strong>
p(rint) function, to the “Date:” string
seen in the document's “Information
about” page (= cmd), if any. It is
created for use by an external program,
as defined in a lynx.cfg
PRINTER: definition statement. If the
field does not exist for the document,
the variable is set to a null string
under UNIX, or “No Date” under VMS.
LYNX_PRINT_LASTMOD This variable is set by the <strong>Lynx</strong>
p(rint) function, to the Last Mod:
string seen in the document's “Information
about” page (= cmd), if any.
It is created for use by an external
program, as defined in a lynx.cfg
PRINTER: definition statement. If the
field does not exist for the document,
the variable is set to a null string
under UNIX, or “No LastMod” under VMS.
LYNX_PRINT_TITLE This variable is set by the <strong>Lynx</strong>
p(rint) function, to the Linkname:
string seen in the document's “Information
about” page (= cmd), if any.
It is created for use by an external
program, as defined in a lynx.cfg
PRINTER: definition statement. If the
field does not exist for the document,
the variable is set to a null string
under UNIX, or “No Title” under VMS.
LYNX_PRINT_URL This variable is set by the <strong>Lynx</strong>
p(rint) function, to the URL: string
seen in the document's “Information
about” page (= cmd), if any. It is
created for use by an external program,
as defined in a lynx.cfg
PRINTER: definition statement. If the
field does not exist for the document,
the variable is set to a null string
under UNIX, or “No URL” under VMS.
LYNX_VERSION This variable is always set by <strong>Lynx</strong>,
and may be used by an external program
to determine if it was invoked by
<strong>Lynx</strong>. See also the comments in the
distribution's sample mailcap file,
for notes on usage in such a file.
SSL_CERT_DIR Set to the directory containing trusted
certificates.
SSL_CERT_FILE Set to the full path and filename for
your file of trusted certificates.
TERM Normally, this variable is used by
<strong>Lynx</strong> to determine the terminal type
being used to invoke <strong>Lynx</strong>. If, however,
it is unset at startup time (or
has the value “unknown”), or if the
-term command-line option is used,
<strong>Lynx</strong> will set or modify its value
to the user specified terminal type
(for the <strong>Lynx</strong> execution environment).
Note: If set/modified by <strong>Lynx</strong>, the values of
the LINES and/or COLUMNS environment
variables may also be changed.
</pre>
<h2><a name="cgi" id="cgi">Simulated CGI Support</a></h2>
<p>If built with the cgi-links option enabled,
<strong>Lynx</strong> allows access to a cgi script directly
without the need for an http daemon.</p>
<p>When executing such “lynxcgi scripts” (if
enabled), the following variables may be set for simulating a CGI
environment:</p>
<pre>
CONTENT_LENGTH
CONTENT_TYPE
DOCUMENT_ROOT
HTTP_ACCEPT_CHARSET
HTTP_ACCEPT_LANGUAGE
HTTP_USER_AGENT
PATH_INFO
PATH_TRANSLATED
QUERY_STRING
REMOTE_ADDR
REMOTE_HOST
REQUEST_METHOD
SERVER_SOFTWARE
</pre>
<p>Other environment variables are not inherited by the script,
unless they are provided via a LYNXCGI_ENVIRONMENT statement in
the configuration file. See the lynx.cfg file, and the (draft)
CGI 1.1 Specification
<http://Web.Golux.Com/coar/cgi/draft-coar-cgi-v11-00.txt>
for the definition and usage of these variables.</p>
<p>The CGI Specification, and other associated documentation,
should be consulted for general information on CGI script
programming.</p>
<h2><a name="language" id="language">Native Language Support</a></h2>
<p>If configured and installed with Native Language Support,
<strong>Lynx</strong> will display status and other messages in
your local language. See the file ABOUT_NLS in the source
distribution, or at your local GNU site, for more information
about internationalization.</p>
<p>The following environment variables may be used to alter
default settings:</p>
<pre>
LANG This variable, if set, will override
the default message language. It is
an ISO 639 two-letter code identifying
the language. Language codes are NOT
the same as the country codes given in
ISO 3166.
LANGUAGE This variable, if set, will override
the default message language. This is a
GNU extension that has higher priority for
setting the message catalog than LANG or
LC_ALL.
LC_ALL and
LC_MESSAGES These variables, if set, specify the
notion of native language formatting
style. They are POSIXly correct.
LINGUAS This variable, if set prior to configuration,
limits the installed languages to specific values.
It is a space-separated list of two-letter codes.
Currently, it is hard-coded to a wish list.
NLSPATH This variable, if set, is used as the
path prefix for message catalogs.
</pre>
<h2><a name="proxy" id="proxy">Proxy details and examples</a></h2>
<p>To set your site's NTTP server as the default host for news
reading and posting via <strong>Lynx</strong>, set the
environment variable NNTPSERVER so that it points to its Internet
address. The variable “NNTPSERVER” is used to specify
the host which will be used as the default for news URLs.</p>
<dl>
<dt>UNIX</dt>
<dd>
<pre>
setenv NNTPSERVER "news.server.dom"
</pre>
</dd>
<dt>VMS</dt>
<dd>
<pre>
define/system NNTPSERVER "news.server.dom"
</pre>
</dd>
</dl>
<p><strong>Lynx</strong> still supports use of gateway servers,
with the servers specified via the variables
“WWW_access_GATEWAY”, where “access” is
lower case and can be “http”, “ftp”,
“gopher” or “wais”. Most of the gateway
servers have been discontinued, but
“http://www.w3.org:8001” is available for wais
searches (note that you do not include a terminal “/”
for gateways, but do for proxies; see below).</p>
<p><strong>Lynx</strong> version 2.2 and beyond supports the use
of proxy servers that can act as firewall gateways and caching
servers. They are preferable to the older gateway servers. Each
protocol used by <strong>Lynx</strong> can be mapped separately
using <em>PROTOCOL</em>_proxy environment variables as shown
below:</p>
<dl>
<dt>UNIX</dt>
<dd>
<blockquote>
<pre>
setenv http_proxy "http://some.server.dom:port/"
setenv https_proxy "http://some.server.dom:port/"
setenv ftp_proxy "http://some.server.dom:port/"
setenv gopher_proxy "http://some.server.dom:port/"
setenv news_proxy "http://some.server.dom:port/"
setenv newspost_proxy "http://some.server.dom:port/"
setenv newsreply_proxy "http://some.server.dom:port/"
setenv snews_proxy "http://some.server.dom:port/"
setenv snewspost_proxy "http://some.server.dom:port/"
setenv snewsreply_proxy "http://some.server.dom:port/"
setenv nntp_proxy "http://some.server.dom:port/"
setenv wais_proxy "http://some.server.dom:port/"
setenv finger_proxy "http://some.server.dom:port/"
setenv cso_proxy "http://some.server.dom:port/"
</pre>
</blockquote>
</dd>
<dt>VMS</dt>
<dd>
<blockquote>
<pre>
define "http_proxy" "http://some.server.dom:port/"
define "https_proxy" "http://some.server.dom:port/"
define "ftp_proxy" "http://some.server.dom:port/"
define "gopher_proxy" "http://some.server.dom:port/"
define "news_proxy" "http://some.server.dom:port/"
define "newspost_proxy" "http://some.server.dom:port/"
define "newsreply_proxy" "http://some.server.dom:port/"
define "snews_proxy" "http://some.server.dom:port/"
define "snewspost_proxy" "http://some.server.dom:port/"
define "snewsreply_proxy" "http://some.server.dom:port/"
define "nntp_proxy" "http://some.server.dom:port/"
define "wais_proxy" "http://some.server.dom:port/"
define "finger_proxy" "http://some.server.dom:port/"
define "cso_proxy" "http://some.server.dom:port/"
</pre>
</blockquote>
<p>(Encase *BOTH* strings in double-quotes to maintain lower
case for the <em>PROTOCOL</em>_proxy variable and for the
http access type; include /system if you want proxying for
all clients on your system.)</p>
</dd>
</dl>
<p>If you wish to override the use of a proxy server for specific
hosts or entire domains you may use the “no_proxy”
environment variable. The no_proxy variable can be a
comma-separated list of strings defining no-proxy zones in the
DNS domain name space. If a tail substring of the domain-path for
a host matches one of these strings, transactions with that node
will not be proxied. Here is an example use of
“no_proxy”:</p>
<dl>
<dt>UNIX</dt>
<dd>
<pre>
setenv no_proxy "host.domain.dom, domain1.dom, domain2"
</pre>
</dd>
<dt>VMS</dt>
<dd>
<pre>
define "no_proxy" "host.domain.dom, domain1.dom, domain2"
</pre>
</dd>
</dl>
<p>You can include a port number in the no_proxy list to override
use of a proxy server for the host accessed via that port, but
not via other ports. For example, if you use
“host.domain.dom:119” and/or
“host.domain.dom:210”, then news (port 119) URLs
and/or any wais (port 210) searches on that host would be
excluded, but http, ftp, and gopher services (if normally
proxied) would still be included, as would any news or wais
services on other hosts.</p>
<p>Warning: Note that setting “il” as an entry in
this list will block proxying for the .mil domain as well as the
.il domain. If the entry is “.il” this will not
happen.</p>
<p>If you wish to override the use of a proxy server completely
(i.e., globally override any existing proxy variables), set the
value of “no_proxy” to “*”. This is the
only allowed use of * in no_proxy.</p>
<p>Note that <strong>Lynx</strong> treats file URLs on the local
host as requests for direct access to the file, and does not
attempt ftp if that fails. It treats both ftp URLs and file URLs
on remote hosts as ftp URLs, and does not attempt direct file
access for either. If ftp URLs are being proxied, file URLs on a
remote host will be converted to ftp URLs before submission by
<strong>Lynx</strong> to the proxy server, so no special
procedure for inducing the proxy server to handle them is
required. Other WWW clients may require that the http server's
configuration file have “Map file:* ftp:*” in it to
perform that conversion.</p>
<p>If you have not set NNTPSERVER, proxy or no_proxy environment
variables you can set them at run time via the configuration file
lynx.cfg (this will not override external settings).</p>
<h2><a name="dos" id="dos">Win32 (95/NT) and 386 DOS</a></h2>
<p>(adapted from “readme.txt” by Wayne Buttles<br>
and “readme.dos” by Doug Kaufman)</p>
<p>Here are some environment variables that should be set,
usually in a batch file that runs the <strong>Lynx</strong>
executable. Make sure that you have enough room left in your
environment. You may need to change your “SHELL=”
setting in config.sys. In addition, <strong>Lynx</strong> looks
for a “SHELL” environment variable when shelling to
DOS. If you wish to preserve the environment space when shelling,
put a line like this in your AUTOEXEC.BAT file also “SET
SHELL=C:\COMMAND.COM /E:2048”. It should match
CONFIG.SYS.</p>
<pre>
HOME Where to keep the bookmark file and personal config files.
TEMP or TMP Bookmarks are kept here with no HOME. Temp files here.
USER Set to your login name
LYNX_CFG Set to the full path and filename for lynx.cfg
</pre>
<p>386 version only:<br></p>
<pre>
WATTCP.CFG Set to the full path for the WATTCP.CFG directory
</pre>
<p>(Depending on how you compiled libtcp.a, you may have to use
WATCONF.)</p>
<p>Define these in your batch file for running
<strong>Lynx</strong>. For example, if your application line is
“D:\win32\lynx.bat”, lynx.bat for Win32 may look
like:</p>
<pre>
@ECHO OFF
set home=d:\win32
set temp=d:\tmp
set lynx_cfg=d:\win32\lynx.cfg
d:\win32\lynx.exe %1 %2 %3 %4 %5
</pre>
<p>In lynx_386, a typical batch file might look like:</p>
<pre>
@echo off
set HOME=f:/lynx2-8
set USER=your_login_name
set LYNX_CFG=%HOME%/lynx.cfg
set WATTCP.CFG=%HOME%
f:\lynx2-8\lynx %1 %2 %3 %4 %5 %6 %7 %8 %9
</pre>
<p>You will also need to make sure that the WATTCP.CFG file has
the correct information for IP number, Gateway, Netmask, and
Domain Name Server. This can also be automated in the batch
file.</p>
</body>
</html>
|
