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