1.\" $NetBSD: environ.7,v 1.3 1994/11/30 19:07:08 jtc Exp $ 2.\" 3.\" Copyright (c) 1983, 1990, 1993 4.\" The Regents of the University of California. All rights reserved. 5.\" 6.\" Redistribution and use in source and binary forms, with or without 7.\" modification, are permitted provided that the following conditions 8.\" are met: 9.\" 1. Redistributions of source code must retain the above copyright 10.\" notice, this list of conditions and the following disclaimer. 11.\" 2. Redistributions in binary form must reproduce the above copyright 12.\" notice, this list of conditions and the following disclaimer in the 13.\" documentation and/or other materials provided with the distribution. 14.\" 3. All advertising materials mentioning features or use of this software 15.\" must display the following acknowledgement: 16.\" This product includes software developed by the University of 17.\" California, Berkeley and its contributors. 18.\" 4. Neither the name of the University nor the names of its contributors 19.\" may be used to endorse or promote products derived from this software 20.\" without specific prior written permission. 21.\" 22.\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 23.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 24.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 25.\" ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 26.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 27.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 28.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 29.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 30.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 31.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 32.\" SUCH DAMAGE. 33.\" 34.\" @(#)environ.7 8.3 (Berkeley) 4/19/94 35.\" 36.Dd April 19, 1994 37.Dt ENVIRON 7 38.Os BSD 4.2 39.Sh NAME 40.Nm environ 41.Nd user environment 42.Sh SYNOPSIS 43.Ar extern char **environ ; 44.Sh DESCRIPTION 45An array of strings called the 46.Ar environment 47is made available by 48.Xr execve 2 49when a process begins. By convention these strings have the form 50.Dq Ar name=value . 51The following names are used by various commands: 52.Bl -tag -width BLOCKSIZE 53.It Ev BLOCKSIZE 54The size of the block units used by several commands, most notably 55.Xr df 1 , 56.Xr du 1 57and 58.Xr ls 1 . 59BLOCKSIZE may be specified in units of a byte by specifying a number, 60in units of a kilobyte by specifying a number followed by ``K'' or 61``k'', in units of a megabyte by specifying a number followed by ``M'' 62or ``m'' and in units of a gigabyte by specifying a number followed 63by ``G'' or ``g''. 64Sizes less than 512 bytes or greater than a gigabyte are ignored. 65.It Ev EXINIT 66A startup list of commands read by 67.Xr ex 1 , 68.Xr edit 1 , 69and 70.Xr vi 1 . 71.It Ev HOME 72A user's login directory, set by 73.Xr login 1 74from the password file 75.Xr passwd 5 . 76.It Ev PATH 77The sequence of directories, separated by colons, searched by 78.Xr csh 1 , 79.Xr sh 1 , 80.Xr system 3 , 81.Xr execvp 3 , 82etc, when looking for an executable file. 83PATH is set to ``:/usr/ucb:/bin:/usr/bin'' initially by 84.Xr login 1 . 85.It Ev PRINTER 86The name of the default printer to be used by 87.Xr lpr 1 , 88.Xr lpq 1 , 89and 90.Xr lprm 1 . 91.It Ev SHELL 92The full pathname of the user's login shell. 93.It Ev TERM 94The kind of terminal for which output is to be prepared. 95This information is used by commands, such as 96.Xr nroff 1 97or 98.Xr plot 1 99which may exploit special terminal capabilities. See 100.Pa /usr/share/misc/termcap 101.Pq Xr termcap 5 102for a list of terminal types. 103.It Ev TERMCAP 104The string describing the terminal in TERM, or, if 105it begins with a '/', the name of the termcap file. 106See 107.Ev TERMPATH 108below, 109.Xr termcap 5 , 110and 111.Xr termcap . 112.It Ev TERMPATH 113A sequence of pathnames of termcap files, separated by colons or spaces, 114which are searched for terminal descriptions in the order listed. Having 115no 116.Ev TERMPATH 117is equivalent to a 118.Ev TERMPATH 119of 120.Dq Pa $HOME/.termcap:/etc/termcap . 121.Ev TERMPATH 122is ignored if 123.Ev TERMCAP 124contains a full pathname. 125.It Ev TMPDIR 126The directory in which to store temporary files. 127Most applications use either 128.Dq /tmp 129or 130.Dq /var/tmp . 131Setting this variable will make them use another directory. 132.It Ev TZ 133The timezone to use when displaying dates. 134The normal format is a pathname relative to 135.Dq /usr/share/zoneinfo . 136For example, the command 137.Dq env TZ=US/Pacific date 138displays the current time in California. 139See 140.Xr tzset 3 141for more information. 142.It Ev USER 143The login name of the user. 144.El 145.Pp 146Further names may be placed in the environment by the 147.Xr export 148command and 149.Ar name=value 150arguments in 151.Xr sh 1 , 152or by the 153.Xr setenv 154command if you use 155.Xr csh 1 . 156It is unwise to change certain 157.Xr sh 1 158variables that are frequently exported by 159.Pa .profile 160files, such as 161.Ev MAIL , 162.Ev PS1 , 163.Ev PS2 , 164and 165.Ev IFS , 166unless you know what you are doing. 167.Sh SEE ALSO 168.Xr csh 1 , 169.Xr ex 1 , 170.Xr login 1 , 171.Xr sh 1 , 172.Xr execve 2 , 173.Xr execle 3 , 174.Xr system 3 , 175.Xr termcap 3 , 176.Xr termcap 5 177.Sh HISTORY 178The 179.Nm environ 180manual page appeared in 181.Bx 4.2 . 182