SysIII/usr/src/man/man7/environ.7

.TH ENVIRON 7
.SH NAME
environ \- user environment
.SH DESCRIPTION
An array of strings called the ``environment'' is
made available by
.IR exec (2)
when a process begins.
By convention, these strings have the form
``name=value''.
The following names are used by various commands:
.PP
.PD 0
.TP
.SM
.B PATH
The sequence of directory prefixes that
.IR sh (1),
.IR time (1),
.IR nice (1),
.IR nohup (1),
etc.,
apply in searching for a file known by an incomplete path name.
The prefixes are separated by
colons
.RB ( \^:\^ ).
.IR Login (1)
sets
.SM
.BR PATH\*S=:/bin:/usr/bin .
.TP
.SM
.B HOME
Name of the user's login directory, set by
.IR login (1)
from the password file
.IR passwd (5).
.TP
.SM
.B TERM
The kind of terminal for which output is to be prepared.
This information is used by commands, such as
.IR mm (1)
or
.IR tplot (1G),
which may exploit special capabilities of that terminal.
.TP
.SM
.B TZ
Time zone information. The format is
.BI xxx n zzz
where
.B xxx
is standard local time zone abbreviation,
.I n\^
is the difference in hours from
.SM GMT\*S,
and
.B zzz
is the abbreviation for the daylight-saving local time zone,
if any;
for example,
.BR \s-1EST\s+15\s-1EDT\s+1 .
.PD
.PP
Further names may be placed in the environment by
the
.I export\^
command and ``name=value'' arguments in
.IR sh (1),
or by
.IR exec (2).
It is unwise to conflict with
certain shell variables that are frequently exported by
.B .profile
files:
.SM
.BR MAIL \*S,
.SM
.BR PS1 \*S,
.SM
.BR PS2 \*S,
.SM
.BR IFS \*S.
.SH SEE ALSO
env(1), login(1), sh(1), exec(2), getenv(3C), profile(5), term(7).