Table 7-1. Common environment variables
Variable name
Stored information
DISPLAY
used by the X Window system to identify the display server
DOMAIN
domain name
EDITOR
stores your favorite line editor
HISTSIZE
size of the shell history file in number of lines
HOME
path to your home directory
HOSTNAME
local host name
INPUTRC
location of definition file for input devices such as keyboard
LANG
preferred language
LD_LIBRARY_PATH
paths to search for libraries
LOGNAME
login name
MAIL
location of your incoming mail folder
MANPATH
paths to search for man pages
OS
string describing the operating system
OSTYPE
more information about version etc.
PAGER
used by programs like man
which need to know what to do in case output is more than one terminal window.
PATH
search paths for commands
PS1
primary prompt
PS2
secondary prompt
PWD
present working directory
SHELL
current shell
TERM
terminal type
UID
user ID
USER(NAME)
user name
VISUAL
your favorite full-screen editor
XENVIRONMENT
location of your personal settings for X behavior
XFILESEARCHPATH
paths to search for graphical libraries
A lot of variables are not only predefined but also preset, using configuration files. We discuss these in the next section.
