environ — user
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:
- The size of the block units used by several commands, most notably
ls(1). This variable is processed by the
- The user's preferred width in column positions for the terminal. Utilities
such as ls(1) and
who(1) use this to format output into
columns. If unset or empty, utilities will use an
ioctl(2) call to ask the terminal
driver for the width.
- Default editor name.
- A startup list of commands read by ex(1)
- A user's login directory, set by
login(1) from the password file
- This variable configures all programs which use
setlocale(3) to use the specified
locale unless the
LC_* variables are set.
- Overrides the values of
- Locale to be used for ordering of characters. Note that this may also
affect character ranges in regex(3),
e.g., “[A-Z]” may include characters that
“[[:upper:]]” would not, depending on how the specified
locale orders characters.
- Locale to be used for character classification (letter, space, digit,
etc.) and for interpreting byte sequences as multibyte characters.
- Locale to be used for diagnostic messages.
- Locale to be used for interpreting monetary input and formatting
- Locale to be used for interpreting numeric input and formatting
- Locale to be used for interpreting dates input and for formatting
- 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.
- List of directories to be searched for the message catalog referred to by
- Default paginator program. The program specified by this variable is used
ftp(1), etc, to display information
which is longer than the current display.
- The sequence of directories, separated by colons, searched by
execvp(3), etc, when looking for an
PATH is set to ``/usr/bin:/bin''
initially by login(1).
- The name of the default printer to be used by
- The current directory pathname.
- 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(1)
or plot(1) which may exploit special
terminal capabilities. See /usr/share/misc/termcap
(termcap(5)) for a list of terminal
- The string describing the terminal in
TERM, or, if
it begins with a '/', the name of the termcap file. See
TERMPATH below, and
- A sequence of pathnames of termcap files, separated by colons or spaces,
which are searched for terminal descriptions in the order listed. Having
TERMPATH is equivalent to a
TERMPATH is ignored if
TERMCAP contains a full pathname.
- 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.
- 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. See
tzset(3) for more information.
- 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 frequently
exported by .profile files, such as
IFS, unless you
know what you are doing.
The current environment variables can be printed with
printenv(1) or the
printenv built-in command in
Programs can query and modify the environment, using the
environment routines getenv(3),
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
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
routine, defined in
<crt_externs.h>, can be used
to retrieve the address of environ at runtime.
environ manual page appeared in