.\" Copyright (c) 1983, 1990, 1993 .\" The Regents of the University of California. All rights reserved. .\" .\" Redistribution and use in source and binary forms, with or without .\" modification, are permitted provided that the following conditions .\" are met: .\" 1. Redistributions of source code must retain the above copyright .\" notice, this list of conditions and the following disclaimer. .\" 2. Redistributions in binary form must reproduce the above copyright .\" notice, this list of conditions and the following disclaimer in the .\" documentation and/or other materials provided with the distribution. .\" 3. Neither the name of the University nor the names of its contributors .\" may be used to endorse or promote products derived from this software .\" without specific prior written permission. .\" .\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND .\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE .\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE .\" ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE .\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL .\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS .\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) .\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT .\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY .\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF .\" SUCH DAMAGE. .\" .\" @(#)environ.7 8.3 (Berkeley) 4/19/94 .\" $FreeBSD$ .\" .Dd April 12, 2003 .Dt ENVIRON 7 .Os .Sh NAME .Nm environ .Nd user environment .Sh SYNOPSIS .Ar extern char **environ ; .Sh DESCRIPTION An array of strings called the .Ar environment is made available by .Xr execve 2 when a process begins. By convention these strings have the form .Dq Ar name=value . The following names are used by various commands: .Bl -tag -width LC_MONETARY .It Ev BLOCKSIZE The size of the block units used by several commands, most notably .Xr df 1 , .Xr du 1 and .Xr ls 1 . This variable is processed by the .Xr getbsize 3 function. .It Ev COLUMNS The user's preferred width in column positions for the terminal. Utilities such as .Xr ls 1 and .Xr who 1 use this to format output into columns. If unset or empty, utilities will use an .Xr ioctl 2 call to ask the terminal driver for the width. .It Ev EDITOR Default editor name. .It Ev EXINIT A startup list of commands read by .Xr ex 1 and .Xr vi 1 . .It Ev HOME A user's login directory, set by .Xr login 1 from the password file .Xr passwd 5 . .It Ev LANG This variable configures all programs which use .Xr setlocale 3 to use the specified locale unless the .Ev LC_* variables are set. .It Ev LC_ALL Overrides the values of .Ev LC_COLLATE , .Ev LC_CTYPE , .Ev LC_MESSAGES , .Ev LC_MONETARY , .Ev LC_NUMERIC , .Ev LC_TIME and .Ev LANG . .It Ev LC_COLLATE Locale to be used for ordering of strings. .It Ev LC_CTYPE Locale to be used for character classification (letter, space, digit, etc.) and for interpreting byte sequences as multibyte characters. .It Ev LC_MESSAGES Locale to be used for diagnostic messages. .It Ev LC_MONETARY Locale to be used for interpreting monetary input and formatting output. .It Ev LC_NUMERIC Locale to be used for interpreting numeric input and formatting output. .It Ev LC_TIME Locale to be used for interpreting dates input and for formatting output. .It Ev MAIL The location of the user's mailbox instead of the default in /var/mail, used by .Xr mail 1 , .Xr sh 1 , and many other mail clients. .It Ev NLSPATH List of directories to be searched for the message catalog referred to by .Ev LC_MESSAGES . See .Xr catopen 3 . .It Ev PAGER Default paginator program. The program specified by this variable is used by .Xr mail 1 , .Xr man 1 , .Xr ftp 1 , etc, to display information which is longer than the current display. .It Ev PATH The sequence of directories, separated by colons, searched by .Xr csh 1 , .Xr sh 1 , .Xr system 3 , .Xr execvp 3 , etc, when looking for an executable file. .Ev PATH is set to ``/usr/bin:/bin'' initially by .Xr login 1 . .It Ev PRINTER The name of the default printer to be used by .Xr lpr 1 , .Xr lpq 1 , and .Xr lprm 1 . .It Ev PWD The current directory pathname. .It Ev SHELL The full pathname of the user's login shell. .It Ev TERM The kind of terminal for which output is to be prepared. This information is used by commands, such as .Xr nroff 1 or .Xr plot 1 which may exploit special terminal capabilities. See .Pa /usr/share/misc/termcap .Pq Xr termcap 5 for a list of terminal types. .It Ev TERMCAP The string describing the terminal in .Ev TERM , or, if it begins with a '/', the name of the termcap file. See .Ev TERMPATH below, and .Xr termcap 5 . .It Ev TERMPATH A sequence of pathnames of termcap files, separated by colons or spaces, which are searched for terminal descriptions in the order listed. Having no .Ev TERMPATH is equivalent to a .Ev TERMPATH of .Dq Pa $HOME/.termcap:/etc/termcap . .Ev TERMPATH is ignored if .Ev TERMCAP contains a full pathname. .It Ev TMPDIR The directory in which to store temporary files. Most applications use either .Dq /tmp or .Dq /var/tmp . Setting this variable will make them use another directory. .It Ev TZ The timezone to use when displaying dates. The normal format is a pathname relative to .Dq Pa /usr/share/zoneinfo . For example, the command .Dq env TZ=America/Los_Angeles date displays the current time in California. See .Xr tzset 3 for more information. .It Ev USER The login name of the user. .El .Pp Further names may be placed in the environment by the .Ic export command and .Ar name=value arguments in .Xr sh 1 , or by the .Ic setenv command if you use .Xr csh 1 . It is unwise to change certain .Xr sh 1 variables that are frequently exported by .Pa .profile files, such as .Ev MAIL , .Ev PS1 , .Ev PS2 , and .Ev IFS , unless you know what you are doing. .Pp The current environment variables can be printed with .Xr env 1 , .Xr set 1 or .Xr printenv 1 in .Xr sh 1 and .Xr env 1 , .Xr printenv 1 or the .Cm printenv built-in command in .Xr csh 1 . .Sh PROGRAMMING Programs can query and modify the environment, using the environment routines .Xr getenv 3 , .Xr putenv 3 , .Xr setenv 3 and .Xr unsetenv 3 . Direct access can be made through the global variable .Va environ , though it is recommended that changes to the enviroment still be made through the environment routines. .Pp Shared libraries and bundles don't have direct access to .Va environ , which is only available to the loader .Xr ld 1 when a complete program is being linked. The environment routines can still be used, but if direct access to .Va environ is needed, the .Fn _NSGetEnviron routine, defined in .In crt_externs.h , can be used to retrieve the address of .Va environ at runtime. .Sh SEE ALSO .Xr cd 1 , .Xr csh 1 , .Xr env 1 , .Xr ex 1 , .Xr login 1 , .Xr printenv 1 , .Xr sh 1 , .Xr execve 2 , .Xr execle 3 , .Xr getenv 3 , .Xr putenv 3 , .Xr setenv 3 , .Xr unsetenv 3 , .Xr setlocale 3 , .Xr system 3 , .Xr termcap 3 , .Xr termcap 5 .Sh HISTORY The .Nm manual page appeared in .Bx 4.2 .