ENVIRON(7)

NAME
environ - user environment

SYNOPSIS
extern char **environ;

DESCRIPTION
An array of strings called the “environment” is made available by execve(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=:/usr/ucb:/bin:/usr/bin.

ATTPATH, UCBPATH
    The value of PATH when changing to the corresponding universe. Login(1) sets ATTPATH=:/bin:/usr/bin and UCBPATH=:/usr/ucb:/bin:/usr/bin. See universe(1).

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(1) or plot(1G), 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.

ATTSHELL, UCBSHELL
    The value of SHELL when changing to the corresponding universe. Set by login(1) from the shell specified in the password file. See universe(1).

TERMCAP
    The string describing the terminal in TERM, or the name of the termcap file. See termcap(5) and termcap(3X).

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

USER
    The login name of the user.

LOGNAME
    The login name of the user (the same as USER) used by programs in the att universe.

MAIL
    The pathname of the users mailbox.

PRINTER
    The name of the default printer to be used by lpr(1), lpq(1), and lprm(1).

TZ  Time zone information. The format is sssnddd where sss is the standard local time zone abbreviation, n is the difference in hours from GMT, and ddd is the abbreviation for the local daylight-savings time zone (if any), for example EST5EDT or PST8PDT.

MANTROFF
    A string used by man(1) to format a manual page using troff(1). See man(1).

PAGER
    The crt paginator used by man(1) instead of more(1). See man(1).

PARALLEL
    The default parallel factor used by sh(1), make(1), lint(1), and apply(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 execve(2). It is unwise to conflict with certain sh(1) variables that are frequently exported by `.profile' files: PS1, PS2, IFS.

SEE ALSO
csh(1), ex(1), login(1), sh(1), universe(1), execve(2), system(3), termcap(3X), termcap(5)