ENVIRON(5)

NAME
environ - user environment

SYNOPSIS
extern char **environ;

DESCRIPTION
An array of strings called the `environment' is made available by exec(2) when a process begins. By convention these strings have the form `name=value'. The following names are used by various commands:

PATH
    The sequence of directory prefixes that sh, time, nice(1), etc., apply in searching for a file known by an incomplete path name. The prefixes are separated by `:'. Login(1) sets PATH=:/bin:/usr/bin.

HOME
    A user's login directory, set by login(1) from the password file passwd(5).

TERM
    The kind of terminal for which output is to be prepared. This information is used by commands, such as nroff or plot(1), which may exploit special terminal capabilities. See /etc/termcap (termcap(5)) for a list of terminal types.

SHELL
    The file name of the users login shell.

TERMCAP
    The string describing the terminal in TERM, or the name of the termcap file, see termcap(5),termlib(3).

EXINIT
    A startup list of commands read by ex(1), edit(1), and vi(1).

Further names may be placed in the environment by the export command and `name=value' arguments in sh(1), or by the setenv command if you use csh(1). Arguments may also be placed in the environment at the point of an exec(2). It is unwise to conflict with certain sh(1) variables that are frequently exported by `.profile' files: MAIL, PS1, PS2, IFS.

SEE ALSO
csh(1), ex(1), login(1), sh(1), exec(2), system(3), termlib(3), termcap(5), term(7)