ENVIRON(7)           BSD Miscellaneous Information Manual           ENVIRON(7)

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:

     BLOCKSIZE    The size of the block units used by several commands, most
                  notably df(1), du(1) and ls(1).  This variable is processed
                  by the getbsize(3) function.

     COLUMNS      The user's preferred width in column positions for the ter-
                  minal.  Utilities such as ls(1) and who(1) use this to for-
                  mat output into columns.  If unset or empty, utilities will
                  use an ioctl(2) call to ask the terminal driver for the
                  width.

     EDITOR       Default editor name.

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

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

     LANG         This variable configures all programs which use setlocale(3)
                  to use the specified locale unless the LC_* variables are
                  set.

     LC_ALL       Overrides the values of LC_COLLATE, LC_CTYPE, LC_MESSAGES,
                  LC_MONETARY, LC_NUMERIC, LC_TIME and LANG.

     LC_COLLATE   Locale to be used for ordering of strings.

     LC_CTYPE     Locale to be used for character classification (letter,
                  space, digit, etc.) and for interpreting byte sequences as
                  multibyte characters.

     LC_MESSAGES  Locale to be used for diagnostic messages.

     LC_MONETARY  Locale to be used for interpreting monetary input and for-
                  matting output.

     LC_NUMERIC   Locale to be used for interpreting numeric input and format-
                  ting output.

     LC_TIME      Locale to be used for interpreting dates input and for for-
                  matting output.

     MAIL         The location of the user's mailbox instead of the default in
                  /var/mail, used by mail(1), sh(1), and many other mail
                  clients.

     NLSPATH      List of directories to be searched for the message catalog
                  referred to by LC_MESSAGES.  See catopen(3).

     PAGER        Default paginator program.  The program specified by this
                  variable is used by mail(1), man(1), ftp(1), etc, to display
                  information which is longer than the current display.

     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:/bin''
                  initially by login(1).

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

     PWD          The current directory pathname.

     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) or
                  plot(1) which may exploit special terminal capabilities.
                  See /usr/share/misc/termcap (termcap(5)) for a list of ter-
                  minal types.

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

     TERMPATH     A sequence of pathnames of termcap files, separated by
                  colons or spaces, which are searched for terminal descrip-
                  tions 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 timezone to use when displaying dates.  The normal for-
                  mat is a pathname relative to ``/usr/share/zoneinfo''.  For
                  example, the command ``env TZ=America/Los_Angeles date''
                  displays the current time in California.  See tzset(3) for
                  more information.

     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 fre-
     quently 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), set(1) or
     printenv(1) in sh(1) and env(1), printenv(1) or the printenv built-in
     command in csh(1).

PROGRAMMING
     Programs can query and modify the environment, using the environment rou-
     tines getenv(3), putenv(3), setenv(3) and unsetenv(3).  Direct access can
     be made through the global variable environ, though it is recommended
     that changes to the enviroment still be made through the environment rou-
     tines.

     Shared libraries and bundles don't have direct access to environ, which
     is only available to the loader ld(1) when a complete program is being
     linked.  The environment routines can still be used, but if direct access
     to environ is needed, the _NSGetEnviron() routine, defined in
     <crt_externs.h>, can be used to retrieve the address of environ at run-
     time.

SEE ALSO
     cd(1), csh(1), env(1), ex(1), login(1), printenv(1), sh(1), execve(2),
     execle(3), getenv(3), putenv(3), setenv(3), unsetenv(3), setlocale(3),
     system(3), termcap(3), termcap(5)

HISTORY
     The environ manual page appeared in 4.2BSD.

BSD                             April 12, 2003                             BSD