imported>Guy Harris: /* Assignment: PHP */ Link PHP.

2025-11-29T20:14:31Z

Assignment: PHP: Link PHP.

← Previous revision		Revision as of 20:14, 29 November 2025
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	== Design ==		== Design ==
	In all [[Unix]] and [[Unix-like]] systems, as well as on Windows, each process has its own separate set of environment [[Variable (~~programming~~)\|variable]]s. By default, when a process is created, it inherits a duplicate [[run-time environment]] of its parent process, except for explicit changes made by the parent when it creates the child. At the [[Application programming interface\|API]] level, these changes must be done between running <code>fork</code> and <code>exec</code>. Alternatively, from [[command shell]]s such as [[Bash (Unix shell)\|bash]], a user can change environment variables for a particular command invocation by indirectly invoking it via <code>[[env]]</code> or using the <code>ENVIRONMENT_VARIABLE=VALUE <command></code> notation. A running program can access the values of environment variables for configuration purposes.		In all [[Unix]] and [[Unix-like]] systems, as well as on Windows, each process has its own separate set of environment [[Variable (computer science)\|variable]]s. By default, when a process is created, it inherits a duplicate [[run-time environment]] of its parent process, except for explicit changes made by the parent when it creates the child. At the [[Application programming interface\|API]] level, these changes must be done between running <code>fork</code> and <code>exec</code>. Alternatively, from [[command shell]]s such as [[Bash (Unix shell)\|bash]], a user can change environment variables for a particular command invocation by indirectly invoking it via <code>[[env]]</code> or using the <code>ENVIRONMENT_VARIABLE=VALUE <command></code> notation. A running program can access the values of environment variables for configuration purposes.

	[[Shell script]]s and [[Batch file\|batch files]] use environment variables to communicate data and preferences to [[child process]]es. They can also be used to store temporary values for reference later in a shell script. However, in Unix, [[#Unix\|non-exported variables]] are preferred for this as they do not leak outside the process.		[[Shell script]]s and [[Batch file\|batch files]] use environment variables to communicate data and preferences to [[child process]]es. They can also be used to store temporary values for reference later in a shell script. However, in Unix, [[#Unix\|non-exported variables]] are preferred for this as they do not leak outside the process.
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	HELP SETLOCAL		HELP SETLOCAL
	</syntaxhighlight>		</syntaxhighlight>


	In [[PowerShell]], the assignment follows a syntax similar to Unix:		In [[PowerShell]], the assignment follows a syntax similar to Unix:
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	<syntaxhighlight lang="powershell">		<syntaxhighlight lang="powershell">
	$env:VARIABLE = "VALUE"		$env:VARIABLE = "VALUE"
			</syntaxhighlight>

			=== Assignment: PHP ===
			In [[PHP]] the <code>putenv()</code> function should be used.<ref>{{cite web \|title=putenv() \|url=https://www.php.net/manual/en/function.putenv.php \|website=PHP Manual \|publisher=The PHP Documentation Group}}</ref><ref>{{cite web \|title=putenv() PHP Function \|url=https://doc.raided.eu/web/php/functions/putenv/ \|website=The Raided Foundation Docs \|publisher=the Raided Foundation}}</ref>
			<syntaxhighlight lang="php">
			putenv("VARIABLE_NAME"="VALUE");
	</syntaxhighlight>		</syntaxhighlight>

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	In this list, there is no environment variable that refers to the location of the user's ''My Documents'' directory, so there is no standard method for setting a program's home directory to be the ''My Documents'' directory.		In this list, there is no environment variable that refers to the location of the user's ''My Documents'' directory, so there is no standard method for setting a program's home directory to be the ''My Documents'' directory.

	== Pseudo-environment variables ==		==Pseudo-environment variables==
	<!-- Section header used in redirects -->		<!-- Section header used in redirects -->
	The command processors in DOS and Windows also support pseudo-environment variables. These are values that are fetched like environment variables, but are not truly stored in the environment but computed when requested.		The command processors in DOS and Windows also support pseudo-environment variables. These are values that are fetched like environment variables, but are not truly stored in the environment but computed when requested.
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	{{anchor\|System information variable\|Internal variable}}		{{anchor\|System information variable\|Internal variable}}
	Some command-line processors (like [[DR-DOS]] <code>COMMAND.COM</code>,<ref name="Caldera_1998_USER"/> [[Multiuser DOS]] <code>MDOS.COM</code>/<code>[[TMP.EXE]]</code> (Terminal Message Process), JP Software [[4DOS]], [[4OS2]], [[~~4NT (shell)~~\|~~4NT]], [[~~Take Command (~~command line interpreter~~)~~\|Take Command~~]] and Windows [[cmd.exe]]) support a type of pseudo-environment variables named ''system information variables'' (Novell / Caldera terminology)<ref name="Caldera_1998_USER"/> or ''internal variables'' (JP Software terminology),<ref name="4DOS_8.00_HELP"/> which can be used to retrieve various possibly dynamic, but read-only information about the running system in batch jobs. The returned values represent the status of the system in the moment these variables are queried; that is, reading them multiple times in a row may return different values even within the same command; querying them has no direct effect on the system. Since they are not stored in the environment, they are not listed by [[SET (DOS command)\|SET]] and do not exist for external programs to retrieve. If a true environment variable of the same name is defined, it takes precedence over the corresponding variable until the environment variable is deleted again. They are not case-sensitive.		Some command-line processors (like [[DR-DOS]] <code>COMMAND.COM</code>,<ref name="Caldera_1998_USER"/> [[Multiuser DOS]] <code>MDOS.COM</code>/<code>[[TMP.EXE]]</code> (Terminal Message Process), JP Software [[4DOS]], [[4OS2]], [[Take Command Console\|Take Command (formerly 4NT)]] and Windows [[cmd.exe]]) support a type of pseudo-environment variables named ''system information variables'' (Novell / Caldera terminology)<ref name="Caldera_1998_USER"/> or ''internal variables'' (JP Software terminology),<ref name="4DOS_8.00_HELP"/> which can be used to retrieve various possibly dynamic, but read-only information about the running system in batch jobs. The returned values represent the status of the system in the moment these variables are queried; that is, reading them multiple times in a row may return different values even within the same command; querying them has no direct effect on the system. Since they are not stored in the environment, they are not listed by [[SET (DOS command)\|SET]] and do not exist for external programs to retrieve. If a true environment variable of the same name is defined, it takes precedence over the corresponding variable until the environment variable is deleted again. They are not case-sensitive.
	While almost all such variables are prefixed with an [[underscore]] ("<code>_</code>") by 4DOS etc. by convention (f.e. <code>[[#%_SECOND%\|%_SECOND%]]</code>),<ref name="4DOS_8.00_HELP"/> they are not under DR-DOS <code>COMMAND.COM</code> (f.e. <code>[[#%OS_VERSION%\|%OS_VERSION%]]</code>).		While almost all such variables are prefixed with an [[underscore]] ("<code>_</code>") by 4DOS etc. by convention (f.e. <code>[[#%_SECOND%\|%_SECOND%]]</code>),<ref name="4DOS_8.00_HELP"/> they are not under DR-DOS <code>COMMAND.COM</code> (f.e. <code>[[#%OS_VERSION%\|%OS_VERSION%]]</code>).

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	{{Reflist\|refs=		{{Reflist\|refs=
	<ref name="ClassicShS">{{cite book \|title=Classic Shell Scripting \|publisher=[[O'Reilly Media\|O'Reilly]] \|isbn=978-0-596-00595-5 \|date=May 2005 \|author-first1=Arnold \|author-last1=Robbins \|author-first2=Nelson H. F. \|author-last2=Beebe \|editor-last1=Apandi \|editor-first1=Tatiana \|editor-last2=Randal \|editor-first2=Allison \|editor-last3=Witwer \|editor-first3=Adam \|edition=1}}</ref>{{rp\|112}}		<ref name="ClassicShS">{{cite book \|title=Classic Shell Scripting \|publisher=[[O'Reilly Media\|O'Reilly]] \|isbn=978-0-596-00595-5 \|date=May 2005 \|author-first1=Arnold \|author-last1=Robbins \|author-first2=Nelson H. F. \|author-last2=Beebe \|editor-last1=Apandi \|editor-first1=Tatiana \|editor-last2=Randal \|editor-first2=Allison \|editor-last3=Witwer \|editor-first3=Adam \|edition=1}}</ref>{{rp\|112}}
	<ref name="OG_unset">{{cite web \|title=unset - unset values and attributes of variables and functions{{snd}} \|work=Commands & Utilities Reference, [[Single UNIX Specification\|The Single UNIX Specification]] - The Open Group Base Specifications, IEEE Std 1003.1-2008 \|date=2016 \|orig-date=2001 \|edition=Issue 7 \|issue=7 \|publisher=The [[IEEE]] and [[The Open Group]] \|url=~~http~~://pubs.opengroup.org/onlinepubs/9699919799/utilities/V3_chap02.html#unset \|access-date=2017-12-18 \|url-status=live \|archive-url=https://web.archive.org/web/20171218175244/http://pubs.opengroup.org/onlinepubs/9699919799/utilities/V3_chap02.html \|archive-date=2017-12-18}}</ref>		<ref name="OG_unset">{{cite web \|title=unset - unset values and attributes of variables and functions{{snd}} \|work=Commands & Utilities Reference, [[Single UNIX Specification\|The Single UNIX Specification]] - The Open Group Base Specifications, IEEE Std 1003.1-2008 \|date=2016 \|orig-date=2001 \|edition=Issue 7 \|issue=7 \|publisher=The [[IEEE]] and [[The Open Group]] \|url=https://pubs.opengroup.org/onlinepubs/9699919799/utilities/V3_chap02.html#unset \|access-date=2017-12-18 \|url-status=live \|archive-url=https://web.archive.org/web/20171218175244/http://pubs.opengroup.org/onlinepubs/9699919799/utilities/V3_chap02.html \|archive-date=2017-12-18}}</ref>
	<ref name="Bash_unset">{{cite web \|title=The unset builtin command \|date=2015-07-31 \|orig-date=2011 \|author=fgrose \|work=Bash Hackers Wiki \|url=http://wiki.bash-hackers.org/commands/builtin/unset \|access-date=2017-12-18 \|url-status=live \|archive-url=https://web.archive.org/web/20171218175214/http://wiki.bash-hackers.org/commands/builtin/unset \|archive-date=2017-12-18}}</ref>		<ref name="Bash_unset">{{cite web \|title=The unset builtin command \|date=2015-07-31 \|orig-date=2011 \|author=fgrose \|work=Bash Hackers Wiki \|url=http://wiki.bash-hackers.org/commands/builtin/unset \|access-date=2017-12-18 \|url-status=live \|archive-url=https://web.archive.org/web/20171218175214/http://wiki.bash-hackers.org/commands/builtin/unset \|archive-date=2017-12-18}}</ref>
	<ref name="appdata">{{cite web \|title=Store and retrieve settings and other app data \|date=2017-11-14 \|author-first1=Mike \|author-last1=Jacobs \|author-first2=Alexander \|author-last2=Koren \|author-first3=Michael \|author-last3=Satran \|publisher=[[Microsoft]] \|url=https://docs.microsoft.com/en-us/windows/uwp/app-settings/store-and-retrieve-app-data \|access-date=2017-12-18 \|url-status=live \|archive-url=https://web.archive.org/web/20171218175200/https://docs.microsoft.com/de-de/windows/uwp/design/app-settings/store-and-retrieve-app-data \|archive-date=2017-12-18}}</ref>		<ref name="appdata">{{cite web \|title=Store and retrieve settings and other app data \|date=2017-11-14 \|author-first1=Mike \|author-last1=Jacobs \|author-first2=Alexander \|author-last2=Koren \|author-first3=Michael \|author-last3=Satran \|publisher=[[Microsoft]] \|url=https://docs.microsoft.com/en-us/windows/uwp/app-settings/store-and-retrieve-app-data \|access-date=2017-12-18 \|url-status=live \|archive-url=https://web.archive.org/web/20171218175200/https://docs.microsoft.com/de-de/windows/uwp/design/app-settings/store-and-retrieve-app-data \|archive-date=2017-12-18}}</ref>
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	<ref name="Allen_2005">{{cite web \|author-first1=William \|author-last1=Allen \|author-first2=Linda \|author-last2=Allen \|title=Windows 95/98/ME ERRORLEVELs \|url=http://www.allenware.com/mcsw/errorlevels.zip \|url-status=dead \|archive-url=https://web.archive.org/web/20110707113138/http://www.allenware.com/mcsw/errorlevels.zip \|archive-date=2011-07-07}}</ref>		<ref name="Allen_2005">{{cite web \|author-first1=William \|author-last1=Allen \|author-first2=Linda \|author-last2=Allen \|title=Windows 95/98/ME ERRORLEVELs \|url=http://www.allenware.com/mcsw/errorlevels.zip \|url-status=dead \|archive-url=https://web.archive.org/web/20110707113138/http://www.allenware.com/mcsw/errorlevels.zip \|archive-date=2011-07-07}}</ref>
	<ref name="FD_2003_Errorlevel">{{cite web \|title=MS-DOS errorlevels \|author-first1=Eric \|author-last1=Auer \|author-first2=Matthias R. \|author-last2=Paul \|author-first3=Jim \|author-last3=Hall \|author-link3=Jim Hall (programmer) \|date=2015-12-24 \|orig-date=2003-12-31 \|url=http://www.freedos.org/technotes/technote/207.html \|url-status=dead \|archive-url=https://web.archive.org/web/20151224202118/http://www.freedos.org/technotes/technote/207.html \|archive-date=2015-12-24}}</ref>		<ref name="FD_2003_Errorlevel">{{cite web \|title=MS-DOS errorlevels \|author-first1=Eric \|author-last1=Auer \|author-first2=Matthias R. \|author-last2=Paul \|author-first3=Jim \|author-last3=Hall \|author-link3=Jim Hall (programmer) \|date=2015-12-24 \|orig-date=2003-12-31 \|url=http://www.freedos.org/technotes/technote/207.html \|url-status=dead \|archive-url=https://web.archive.org/web/20151224202118/http://www.freedos.org/technotes/technote/207.html \|archive-date=2015-12-24}}</ref>
	<ref name="Paul_2017">{{cite web \|title=The continuing saga of Windows 3.1 in enhanced mode on OmniBook 300 \|author-first=Matthias R. \|author-last=Paul \|orig-date=2017-08-07 \|date=2017-08-14 \|work=MoHPC - the Museum of HP Calculators \|url=~~http~~://hpmuseum.org/forum/thread-8774-post-77196.html#pid77196 \|access-date=2018-05-01 \|url-status=live \|archive-url=https://web.archive.org/web/20180501185933/http://hpmuseum.org/forum/thread-8774-post-77196.html \|archive-date=2018-05-01 \|quote=[…] set DRSYS=ON (optional to tell SYS you are aware of the fact that you're running it in a foreign environment and want to proceed anyway without having to individually ACK some warnings and extra info screens displayed in this scenario otherwise) […]}}</ref>		<ref name="Paul_2017">{{cite web \|title=The continuing saga of Windows 3.1 in enhanced mode on OmniBook 300 \|author-first=Matthias R. \|author-last=Paul \|orig-date=2017-08-07 \|date=2017-08-14 \|work=MoHPC - the Museum of HP Calculators \|url=https://hpmuseum.org/forum/thread-8774-post-77196.html#pid77196 \|access-date=2018-05-01 \|url-status=live \|archive-url=https://web.archive.org/web/20180501185933/http://hpmuseum.org/forum/thread-8774-post-77196.html \|archive-date=2018-05-01 \|quote=[…] set DRSYS=ON (optional to tell SYS you are aware of the fact that you're running it in a foreign environment and want to proceed anyway without having to individually ACK some warnings and extra info screens displayed in this scenario otherwise) […]}}</ref>
	<ref name="Paul_1997_SETENV">{{cite web \|title=SETENV v1.11 \|author-first=Matthias R. \|author-last=Paul \|date=1997-05-27 \|orig-date=1996 \|url=http://www.uni-bonn.de:80/~uzs180/mpdokeng.html#M.SETENV \|url-status=dead \|archive-url=https://web.archive.org/web/20090215001349/http://www.uni-bonn.de/~uzs180/mpdokeng.html#M.SETENV \|archive-date=2009-02-15 \|quote=[…] SETENV […] to hide and later restore the […] pre-environment […] By using SETENV.COM you can save some KiloBytes of rare DOS memory […] depending on the number of drivers loaded by [[INSTALL (CONFIG.SYS directive)\|INSTALL=]]/[[INSTALLHIGH (CONFIG.SYS directive)\|INSTALLHIGH=]]/[[HIINSTALL (CONFIG.SYS directive)\|HIINSTALL=]] and the current size of the pre-environment. […] this original […] feature cannot be found in any known memory manager/optimizer. […] \|access-date=2019-08-09}}</ref>		<ref name="Paul_1997_SETENV">{{cite web \|title=SETENV v1.11 \|author-first=Matthias R. \|author-last=Paul \|date=1997-05-27 \|orig-date=1996 \|url=http://www.uni-bonn.de:80/~uzs180/mpdokeng.html#M.SETENV \|url-status=dead \|archive-url=https://web.archive.org/web/20090215001349/http://www.uni-bonn.de/~uzs180/mpdokeng.html#M.SETENV \|archive-date=2009-02-15 \|quote=[…] SETENV […] to hide and later restore the […] pre-environment […] By using SETENV.COM you can save some KiloBytes of rare DOS memory […] depending on the number of drivers loaded by [[INSTALL (CONFIG.SYS directive)\|INSTALL=]]/[[INSTALLHIGH (CONFIG.SYS directive)\|INSTALLHIGH=]]/[[HIINSTALL (CONFIG.SYS directive)\|HIINSTALL=]] and the current size of the pre-environment. […] this original […] feature cannot be found in any known memory manager/optimizer. […] \|access-date=2019-08-09}}</ref>
	<ref name="PTS-DOS_2000">{{cite web \|title=PTS-DOS 2000 Pro User Manual \|url=http://download.paragon-software.com/doc/manual_dos_eng.pdf \|access-date=2018-05-12 \|url-status=live \|archive-url=https://web.archive.org/web/20180512094512/http://download.paragon-software.com/doc/manual_dos_eng.pdf \|archive-date=2018-05-12}}</ref>		<ref name="PTS-DOS_2000">{{cite web \|title=PTS-DOS 2000 Pro User Manual \|url=http://download.paragon-software.com/doc/manual_dos_eng.pdf \|access-date=2018-05-12 \|url-status=live \|archive-url=https://web.archive.org/web/20180512094512/http://download.paragon-software.com/doc/manual_dos_eng.pdf \|archive-date=2018-05-12}}</ref>
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	* {{man\|7\|environ\|Solaris}}		* {{man\|7\|environ\|Solaris}}
	* {{cite web \|title=Environment Variables Wiki \|url=http://environmentvariables.org \|archive-url=https://web.archive.org/web/20190427235415/http://environmentvariables.org/ \|archive-date=2019-04-27}}		* {{cite web \|title=Environment Variables Wiki \|url=http://environmentvariables.org \|archive-url=https://web.archive.org/web/20190427235415/http://environmentvariables.org/ \|archive-date=2019-04-27}}
	* [~~http~~://msdn.microsoft.com/en-us/library/windows/desktop/bb776899%28v=vs.85%29.aspx User Environment Variables]		* [https://msdn.microsoft.com/en-us/library/windows/desktop/bb776899%28v=vs.85%29.aspx User Environment Variables]
	* [https://web.archive.org/web/20180511150138/https://www.setx.cc/ fix setx.exe not found bug]		* [https://web.archive.org/web/20180511150138/https://www.setx.cc/ fix setx.exe not found bug]

imported>BrandyBuizel: grammar

2025-06-22T01:26:13Z

grammar

← Previous revision		Revision as of 01:26, 22 June 2025
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	;{{anchor\|$TZ}}<code>$TZ</code>: Refers to [[time zone]]. It can be in several formats, either specifying the time zone itself or referencing a file (in <code>/usr/share/zoneinfo</code>).		;{{anchor\|$TZ}}<code>$TZ</code>: Refers to [[time zone]]. It can be in several formats, either specifying the time zone itself or referencing a file (in <code>/usr/share/zoneinfo</code>).

	;{{anchor\|$BROWSER}}<code>$BROWSER</code>: Contains a colon-separated list of a user's [[web browser]] preferences, for use by programs that need to allow the user to view content at a [[URL]]. The browsers in the list are intended to be attempted from first to last, stopping after the first one that succeeds. This arrangement allows for fallback behavior in different environments, e.g., in an [[X Window System\|X11]] environment, a graphical browser (such as [[Firefox]]) can be used, but in a console environment a terminal-base browser (such a [[Lynx (web browser)\|Lynx]]) can be used. A <code>%s</code> token may be present to specify where the URL should be placed; otherwise the browser should be launched with the URL as the first argument.<ref name="ESR_2002_BROWSER"/><ref name="LWN_2001_BROWSER"/><ref name="PERL_ENV_BROWSER"/><ref name="PYTHON_WEBBROWSER"/><ref name="DEBIAN_DFLT_WEB_BROWSER"/>		;{{anchor\|$BROWSER}}<code>$BROWSER</code>: Contains a colon-separated list of a user's [[web browser]] preferences, for use by programs that need to allow the user to view content at a [[URL]]. The browsers in the list are intended to be attempted from first to last, stopping after the first one that succeeds. This arrangement allows for fallback behavior in different environments, e.g., in an [[X Window System\|X11]] environment, a graphical browser (such as [[Firefox]]) can be used, but in a console environment a terminal-base browser (such as [[Lynx (web browser)\|Lynx]]) can be used. A <code>%s</code> token may be present to specify where the URL should be placed; otherwise the browser should be launched with the URL as the first argument.<ref name="ESR_2002_BROWSER"/><ref name="LWN_2001_BROWSER"/><ref name="PERL_ENV_BROWSER"/><ref name="PYTHON_WEBBROWSER"/><ref name="DEBIAN_DFLT_WEB_BROWSER"/>

	==={{anchor\|DOS-ENV}}DOS ===		==={{anchor\|DOS-ENV}}DOS ===

imported>Kvng: ws

2025-06-04T14:13:08Z

← Previous revision		Revision as of 14:13, 4 June 2025
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	By convention, names of environment variables are normally expressed in all capital letters. This helps keep environment variables distinctly different from other variables and identifiers used in programming codes. Nevertheless, note that case sensitivity in environment variable names differs between operating systems. That is, Unix-like operating systems are case-sensitive with respect to environment variable names, while DOS, OS/2, and Windows are not case-sensitive.		By convention, names of environment variables are normally expressed in all capital letters. This helps keep environment variables distinctly different from other variables and identifiers used in programming codes. Nevertheless, note that case sensitivity in environment variable names differs between operating systems. That is, Unix-like operating systems are case-sensitive with respect to environment variable names, while DOS, OS/2, and Windows are not case-sensitive.



	=== Unix ===		=== Unix ===

imported>Frap: /* DOS, OS/2 and Windows */

2025-05-31T12:21:09Z

DOS, OS/2 and Windows

Show changes

← Previous revision		Revision as of 01:26, 22 June 2025
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	;{{anchor\|$TZ}}<code>$TZ</code>: Refers to [[time zone]]. It can be in several formats, either specifying the time zone itself or referencing a file (in <code>/usr/share/zoneinfo</code>).		;{{anchor\|$TZ}}<code>$TZ</code>: Refers to [[time zone]]. It can be in several formats, either specifying the time zone itself or referencing a file (in <code>/usr/share/zoneinfo</code>).

	;{{anchor\|$BROWSER}}<code>$BROWSER</code>: Contains a colon-separated list of a user's [[web browser]] preferences, for use by programs that need to allow the user to view content at a [[URL]]. The browsers in the list are intended to be attempted from first to last, stopping after the first one that succeeds. This arrangement allows for fallback behavior in different environments, e.g., in an [[X Window System\|X11]] environment, a graphical browser (such as [[Firefox]]) can be used, but in a console environment a terminal-base browser (such a [[Lynx (web browser)\|Lynx]]) can be used. A <code>%s</code> token may be present to specify where the URL should be placed; otherwise the browser should be launched with the URL as the first argument.<ref name="ESR_2002_BROWSER"/><ref name="LWN_2001_BROWSER"/><ref name="PERL_ENV_BROWSER"/><ref name="PYTHON_WEBBROWSER"/><ref name="DEBIAN_DFLT_WEB_BROWSER"/>		;{{anchor\|$BROWSER}}<code>$BROWSER</code>: Contains a colon-separated list of a user's [[web browser]] preferences, for use by programs that need to allow the user to view content at a [[URL]]. The browsers in the list are intended to be attempted from first to last, stopping after the first one that succeeds. This arrangement allows for fallback behavior in different environments, e.g., in an [[X Window System\|X11]] environment, a graphical browser (such as [[Firefox]]) can be used, but in a console environment a terminal-base browser (such as [[Lynx (web browser)\|Lynx]]) can be used. A <code>%s</code> token may be present to specify where the URL should be placed; otherwise the browser should be launched with the URL as the first argument.<ref name="ESR_2002_BROWSER"/><ref name="LWN_2001_BROWSER"/><ref name="PERL_ENV_BROWSER"/><ref name="PYTHON_WEBBROWSER"/><ref name="DEBIAN_DFLT_WEB_BROWSER"/>

	==={{anchor\|DOS-ENV}}DOS ===		==={{anchor\|DOS-ENV}}DOS ===

Environment variable - Revision history

imported>Guy Harris: /* Assignment: PHP */ Link PHP.

imported>BrandyBuizel: grammar

imported>Kvng: ws

imported>Frap: /* DOS, OS/2 and Windows */