environ(5)environ(5)NAMEenviron - User environment
SYNOPSIS
extern char **environ;
DESCRIPTION
An array of strings called the environment is made available by the
execve() function when a process begins. By convention these strings
have the form name=value. The following names are used by various com‐
mands: A startup list of commands read by ex, edit, and vi. A user's
login directory, set by login from the password file passwd. The
sequence of directories, separated by colons, searched by csh, sh, sys‐
tem, execvp, etc, when looking for an executable file. PATH is set to
:/usr/ucb:/bin:/usr/bin initially by login. The name of the default
printer to be used by lpr, lpq, and lprm. The full pathname of the
user's login shell. The kind of terminal for which output is to be
prepared. This information is used by commands, such as nroff which may
exploit special terminal capabilities. � .\" See /usr/share/misc/term‐
cap for a list of terminal types. .\"from TP " .\" Bold under TP !" -->
The string describing the terminal in the TERM environment variable,
or, if it begins with a / (slash), the name of the termcap file. See
TERMPATH below. 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. The login name of the user.
Further names may be placed in the environment by the export command
and name=value arguments in sh, or by the setenv command if you use
csh. It is unwise to change certain sh variables that are frequently
exported by files, such as MAIL, PS1, PS2, and IFS.
SEE ALSO
Functions: exec(2), system(3)
Commands: csh(1), ex(1), login(1), sh(1)environ(5)