$BASH_VERSION # bash version
$EDITOR # default editor
$GROUPS # membership in groups
$HISTFILE # user shell`s history file
$HISTSIZE # how many commands can be stored in bash $HISTFILE
$HOME # home directory
$HOSTNAME # hostname
$LANG # locale for the shell
$LC_* # locale settings that override $LANG
$LC_ALL #
$LD_LIBRARY_PATH # paths to search for libraries
$PATH # paths to search for commands, priority order
$PS1 #
$PS2 #
$PWD # users working directory
$SHLLVL # current shell level
$TZ # current time zone if different from system time zone
$UID # user id
$VISUAL #