environ —user environment
An array of strings called theenvironment is made available byexecve(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 notablydf(1),du(1) andls(1). This variable is processed by thegetbsize(3) function.
COLUMNS- The user's preferred width in column positions for the terminal. Utilities such asls(1) andwho(1) use this to format output into columns. If unset or empty, utilities will use anioctl(2) call to ask the terminal driver for the width.
EDITOR- Default editor name.
EXINIT- A startup list of commands read byex(1) andvi(1).
HOME- A user's login directory, set bylogin(1) from the password filepasswd(5).
LANG- This variable configures all programs which usesetlocale(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 andLANG. LC_COLLATE- Locale to be used for ordering of characters. Note that this may also affect character ranges inregex(3), e.g., “[A-Z]” may include characters that “[[:upper:]]” would not, depending on how the specified locale orders characters.
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 formatting output.
LC_NUMERIC- Locale to be used for interpreting numeric input and formatting output.
LC_TIME- Locale to be used for interpreting dates input and for formatting output.
MAIL- The location of the user's mailbox instead of the default in /var/mail, used bymail(1),sh(1), and many other mail clients.
NLSPATH- List of directories to be searched for the message catalog referred to by
LC_MESSAGES. Seecatopen(3). PAGER- Default paginator program. The program specified by this variable is used bymail(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 bycsh(1),sh(1),system(3),execvp(3), etc, when looking for an executable file.
PATH is set to ``/usr/bin:/bin'' initially bylogin(1). PRINTER- The name of the default printer to be used bylpr(1),lpq(1), andlprm(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 asnroff(1) orplot(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. SeeTERMPATH below, andtermcap(5). 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 aTERMPATH of “$HOME/.termcap:/etc/termcap”.TERMPATH is ignored ifTERMCAP 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 format is a pathname relative to “/usr/share/zoneinfo”. For example, the command “env TZ=America/Los_Angeles date” displays the current time in California. Seetzset(3) for more information.
USER- The login name of the user.
Further names may be placed in the environment by theexport command andname=value arguments insh(1), or by thesetenv command if you usecsh(1). It is unwise to change certainsh(1) variables that are frequently exported by.profile files, such asMAIL,PS1,PS2, andIFS, unless you know what you are doing.
The current environment variables can be printed withenv(1),set(1) orprintenv(1) insh(1) andenv(1),printenv(1) or theprintenv built-in command incsh(1).
Programs can query and modify the environment, using the environment routinesgetenv(3),putenv(3),setenv(3) andunsetenv(3). Direct access can be made through the global variableenviron, though it is recommended that changes to the enviroment still be made through the environment routines.
Shared libraries and bundles don't have direct access toenviron, which is only available to the loaderld(1) when a complete program is being linked. The environment routines can still be used, but if direct access toenviron is needed, the_NSGetEnviron() routine, defined in<crt_externs.h>, can be used to retrieve the address ofenviron at runtime.
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)
Theenviron manual page appeared in4.2BSD.