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(1), time(1), 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(4).

TERM The kind of terminal for which output is to be prepared.  This information is used by commands, such as nroff, more, or vi, which may exploit special terminal capabilities.  See termcap(4) and tset(1) for a list of terminal types. 

SHELL The file name of the user’s login shell. 

TERMCAP The string describing the terminal in TERM, or the name of the termcap file, see termcap(4).

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

USER The login name of the user. 

LOGNAME The login name of the user. 

MAIL The user’s mailbox. 

TZ The user’s time zone. 

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), mail(1), sh(1), tset(1), exec(2), system(3S), TZ(4), termcap(4), tty(7). 

Version 2.4  —  May 08, 1986