1.\" Copyright (c) 1983, 1990 The Regents of the University of California. 2.\" All rights reserved. 3.\" 4.\" %sccs.include.redist.man% 5.\" 6.\" @(#)environ.7 6.5 (Berkeley) 06/24/90 7.\" 8.Dd 9.Dt ENVIRON 7 10.Os BSD 4.2 11.Sh NAME 12.Nm environ 13.Nd user environment 14.Sh SYNOPSIS 15.Ar extern char **environ ; 16.Sh DESCRIPTION 17An array of strings called the 18.Ar environment 19is made available by 20.Xr execve 2 21when a process begins. By convention these strings have the form 22.Dq Ar name=value . 23The following names are used by various commands: 24.Tw Fl 25.Tp Ev EXINIT 26A startup list of commands read by 27.Xr ex 1 , 28.Xr edit 1 , 29and 30.Xr vi 1 . 31.Tp Ev HOME 32A user's login directory, set by 33.Xr login 1 34from the password file 35.Xr passwd 5 . 36.Tp Ev PATH 37The sequence of directories, separated by colons, searched by 38.Xr csh 1 , 39.Xr sh 1 , 40.Xr system 3 , 41.Xr execvp 3 , 42etc, when looking for an executable file. 43PATH is set to ``:/usr/ucb:/bin:/usr/bin'' initially by 44.Xr login 1 . 45.Tp Ev PRINTER 46The name of the default printer to be used by 47.Xr lpr 1 , 48.Xr lpq 1 , 49and 50.Xr lprm 1 . 51.Tp Ev SHELL 52The full pathname of the user's login shell. 53.Tp Ev TERM 54The kind of terminal for which output is to be prepared. 55This information is used by commands, such as 56.Xr nroff 1 57or 58.Xr plot 1 59which may exploit special terminal capabilities. See 60.Pa /usr/share/misc/termcap 61.Pq Xr tmercap 5 62for a list of terminal types. 63.Tp Ev TERMCAP 64The string describing the terminal in TERM, or, if 65it begins with a '/', the name of the termcap file. 66See 67.Ev TERMPATH 68below, 69.Xr termcap 5 , 70and 71.Xr termcap . 72.Tp Ev TERMPATH 73A sequence of pathnames of termcap files, separated by colons or spaces, 74which are searched for terminal descriptions in the order listed. Having 75no 76.Ev TERMPATH 77is equivalent to a 78.Ev TERMPATH 79of 80.Dq Pa $HOME/.termcap:/etc/termcap . 81.Ev TERMPATH 82is ignored if 83.Ev TERMCAP 84contains a full pathname. 85.Tp Ev USER 86The login name of the user. 87.Tp 88.Pp 89Further names may be placed in the environment by the 90.Xr export 91command and 92.Ar name=value 93arguments in 94.Xr sh 1 , 95or by the 96.Xr setenv 97command if you use 98.Xr csh 1 . 99It is unwise to change certain 100.Xr sh 1 101variables that are frequently exported by 102.Pa .profile 103files, such as 104.Ev MAIL , 105.Ev PS1 , 106.Ev PS2 , 107and 108.Ev IFS , 109unless you know what you are doing. 110.Sh SEE ALSO 111.Xr csh 1 , 112.Xr ex 1 , 113.Xr login 1 , 114.Xr sh 1 , 115.Xr execve 2 , 116.Xr execle 3 , 117.Xr system 3 , 118.Xr termcap 3 , 119.Xr termcap 5 120.Sh HISTORY 121.Nm Environ 122appeared in 4.2 BSD. 123