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:

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

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

PATH The sequence of directories, separated by colons, searched
by csh(1), sh(1), system(3), execvp(3), etc., when looking
for an executable file. PATH is set to:

/usr/bin:/usr/ucb:/usr/etc:/home/<hostname>/<username>/bin:
/usr/lib:/usr/local/bin

initially by login(1).

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

SHELL The full pathname of the user’s login shell.

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

TERMCAP The string describing the terminal in TERM, or, if it
begins with a ’/’, the name of the termcap file. See
TERMPATH below, termcap(5), and termcap(3).

TERMPATH A sequence of pathnames of termcap files, separated by
colons or spaces, which are searched for terminal
descriptions in the order listed. Having no TERMPATH is
equivalent to a TERMPATH of
"$HOME/.termcap:/etc/termcap". TERMPATH is ignored if
TERMCAP contains a full pathname.

USER The login name of the user.

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). It is unwise to change certain sh(1) variables
that are frequently exported by .profile files, such as MAIL, PS1,
PS2, and IFS, unless you know what you are doing.

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