An array of strings called the
is made available by
when a process begins.
By convention these strings have the form
The following variables are recognized by various commands:
The size of the block units used by several commands, most notably
May be specified in units of a byte by specifying a number,
in units of a kilobyte by specifying a number followed by
in units of a megabyte by specifying a number followed by
or in units of a gigabyte by specifying a number followed
Sizes less than 512 bytes or greater than a gigabyte are ignored.
A list of startup commands read by
The sequence of directories, separated by colons, searched by
etc. when looking for an executable file.
Initially set to the value of
but expanded to include
The kind of terminal for which output is to be prepared.
This information is used by commands such as
which may exploit special terminal capabilities.
for a list of terminal types.
The string describing the terminal in
or, if it begins with a
the name of the termcap file.
A sequence of pathnames of termcap files, separated by colons or spaces,
which are searched for terminal descriptions in the order listed.
is equivalent to a
is ignored if
contains a full pathname.
The directory in which to store temporary files.
Most applications use either
Setting this variable will make them use another directory.
The time zone to use when displaying dates.
The normal format is a pathname relative to
For example, the command
displays the current time in California.
for more information.
Deprecated synonym of
(for backwards compatibility).
Further names may be placed in the environment by the
or by the
command if you use
It is unwise to change certain
variables that are frequently exported by
files, such as
unless you know what you are doing.
The current environment variables can be printed with