NAME

environ − 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 commands:

EXINITA startup list of commands read by ex, edit, and vi. 

HOMEA user’s login directory, set by login from the password file passwd. 

PATHThe sequence of directories, separated by colons, searched by csh, sh, system, execvp, etc, when looking for an executable file.  PATH is set to :/usr/ucb:/bin:/usr/bin initially by login. 

PRINTERThe name of the default printer to be used by lpr, lpq, and lprm. 

SHELLThe full pathname of the user’s login shell. 

TERMThe 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. 

TERMCAP
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. 

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. 

USERThe 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 .profile files, such as MAIL, PS1, PS2, and IFS. 

RELATED INFORMATION

Functions: exec(2), system(3)

Commands: csh(1), ex(1), login(1), sh(1)