1.\" $OpenBSD: environ.7,v 1.18 2010/10/28 17:55:04 jmc Exp $ 2.\" $NetBSD: environ.7,v 1.4 1995/07/03 19:45:07 jtc Exp $ 3.\" 4.\" Copyright (c) 1983, 1990, 1993 5.\" The Regents of the University of California. All rights reserved. 6.\" 7.\" Redistribution and use in source and binary forms, with or without 8.\" modification, are permitted provided that the following conditions 9.\" are met: 10.\" 1. Redistributions of source code must retain the above copyright 11.\" notice, this list of conditions and the following disclaimer. 12.\" 2. Redistributions in binary form must reproduce the above copyright 13.\" notice, this list of conditions and the following disclaimer in the 14.\" documentation and/or other materials provided with the distribution. 15.\" 3. Neither the name of the University nor the names of its contributors 16.\" may be used to endorse or promote products derived from this software 17.\" without specific prior written permission. 18.\" 19.\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 20.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 21.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 22.\" ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 23.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 24.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 25.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 26.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 27.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 28.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 29.\" SUCH DAMAGE. 30.\" 31.\" @(#)environ.7 8.3 (Berkeley) 4/19/94 32.\" 33.Dd $Mdocdate: October 28 2010 $ 34.Dt ENVIRON 7 35.Os 36.Sh NAME 37.Nm environ 38.Nd user environment 39.Sh SYNOPSIS 40.Ar extern char **environ ; 41.Sh DESCRIPTION 42An array of strings called the 43.Dq environment 44is made available by 45.Xr execve 2 46when a process begins. 47By convention these strings have the form 48.Ar name Ns = Ns Ar value . 49The following variables are recognized by various commands: 50.Bl -tag -width BLOCKSIZE 51.It Ev BLOCKSIZE 52The size of the block units used by several commands, most notably 53.Xr df 1 , 54.Xr du 1 , 55and 56.Xr ls 1 . 57May be specified in units of a byte by specifying a number, 58in units of a kilobyte by specifying a number followed by 59.Sq K 60or 61.Sq k , 62in units of a megabyte by specifying a number followed by 63.Sq M 64or 65.Sq m , 66or in units of a gigabyte by specifying a number followed 67by 68.Sq G 69or 70.Sq g . 71Sizes less than 512 bytes or greater than a gigabyte are ignored. 72.It Ev EXINIT 73A list of startup commands read by 74.Xr ex 1 75and 76.Xr vi 1 . 77.It Ev HOME 78The user's login directory, set by 79.Xr login 1 80from the password file 81.Xr passwd 5 . 82.It Ev LOGNAME 83The login name of the user. 84.It Ev PATH 85The sequence of directories, separated by colons, searched by 86.Xr csh 1 , 87.Xr sh 1 , 88.Xr ksh 1 , 89.Xr system 3 , 90.Xr execvp 3 , 91etc. when looking for an executable file. 92Initially set to the value of 93.Dv _PATH_DEFPATH 94by 95.Xr login 1 , 96traditionally 97.Pa /usr/bin:/bin , 98but expanded to include 99.Pa /usr/sbin , 100.Pa /sbin , 101.Pa /usr/X11R6/bin , 102and 103.Pa /usr/local/bin 104in 105.Ox . 106.It Ev PRINTER 107The name of the default printer to be used by 108.Xr lpq 1 , 109.Xr lpr 1 , 110and 111.Xr lprm 1 . 112.It Ev PWD 113The current working directory. 114.It Ev SHELL 115The full pathname of the user's login shell. 116.It Ev TERM 117The kind of terminal for which output is to be prepared. 118This information is used by commands such as 119.Xr mandoc 1 120which may exploit special terminal capabilities. 121See 122.Pa /usr/share/misc/termcap 123.Pq Xr termcap 5 124for a list of terminal types. 125.It Ev TERMCAP 126The string describing the terminal in 127.Ev TERM , 128or, if it begins with a 129.Ql / , 130the name of the termcap file. 131See 132.Ev TERMPATH 133below, 134.Xr termcap 5 , 135and 136.Xr termcap 3 . 137.It Ev TERMPATH 138A sequence of pathnames of termcap files, separated by colons or spaces, 139which are searched for terminal descriptions in the order listed. 140Having no 141.Ev TERMPATH 142is equivalent to a 143.Ev TERMPATH 144of 145.Pa $HOME/.termcap:/etc/termcap . 146.Ev TERMPATH 147is ignored if 148.Ev TERMCAP 149contains a full pathname. 150.It Ev TMPDIR 151The directory in which to store temporary files. 152Most applications use either 153.Pa /tmp 154or 155.Pa /var/tmp . 156Setting this variable will make them use another directory. 157.It Ev TZ 158The time zone to use when displaying dates. 159The normal format is a pathname relative to 160.Pa /usr/share/zoneinfo . 161For example, the command 162.Ic env TZ=US/Pacific date 163displays the current time in California. 164See 165.Xr tzset 3 166for more information. 167.It Ev USER 168Deprecated synonym of 169.Ev LOGNAME 170(for backwards compatibility). 171.El 172.Pp 173Further names may be placed in the environment by the 174.Ic export 175command and 176.Ar name Ns = Ns Ar value 177arguments in 178.Xr sh 1 , 179or by the 180.Ic setenv 181command if you use 182.Xr csh 1 . 183It is unwise to change certain 184.Xr sh 1 185variables that are frequently exported by 186.Pa .profile 187files, such as 188.Ev MAIL , 189.Ev PS1 , 190.Ev PS2 , 191and 192.Ev IFS , 193unless you know what you are doing. 194.Pp 195The current environment variables can be printed with 196.Xr env 1 197or 198.Xr printenv 1 . 199.Sh SEE ALSO 200.Xr csh 1 , 201.Xr env 1 , 202.Xr ex 1 , 203.Xr login 1 , 204.Xr printenv 1 , 205.Xr sh 1 , 206.Xr execve 2 , 207.Xr execle 3 , 208.Xr getenv 3 , 209.Xr system 3 , 210.Xr termcap 3 , 211.Xr tzset 3 , 212.Xr termcap 5 213.Sh HISTORY 214The 215.Nm 216manual page appeared in 217.Bx 4.2 . 218