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.
The following variables are recognized by various commands:
BLOCKSIZE
The size of the block units used by several commands, most notably
df(1),
du(1),
and
ls(1).
May be specified in units of a byte by specifying a number,
in units of a kilobyte by specifying a number followed by
‘K’
or
‘k’,
in units of a megabyte by specifying a number followed by
‘M’
or
‘m’,
or in units of a gigabyte by specifying a number followed
by
‘G’
or
‘g’.
Sizes less than 512 bytes or greater than a gigabyte are ignored.
EXINIT
A list of startup commands read by
ex(1)
and
vi(1).
HOME
The user's login directory, set by
login(1)
from the password file
passwd(5).
LOGNAME
The login name of the user.
PATH
The sequence of directories, separated by colons, searched by
csh(1),
sh(1),
ksh(1),
system(3),
execvp(3),
etc. when looking for an executable file.
Initially set to the value of
_PATH_DEFPATH
by
login(1),
traditionally
/usr/bin:/bin,
but expanded to include
/usr/sbin,
/sbin,
/usr/X11R6/bin,
and
/usr/local/bin
in
OpenBSD.
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
/usr/share/misc/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.
TMPDIR
The directory in which to store temporary files.
Most applications use either
/tmp
or
/var/tmp.
Setting this variable will make them use another directory.
TZ
The time zone to use when displaying dates.
The normal format is a pathname relative to
/usr/share/zoneinfo.
For example, the command
envTZ=US/Pacific date
displays the current time in California.
See
tzset(3)
for more information.
USER
Deprecated synonym of
LOGNAME
(for backwards compatibility).
Further names may be placed in the environment by the
export
command and
name
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.
The current environment variables can be printed with
env(1)
or
printenv(1).