Linux in a Nutshell, 6th Edition

Other Shell Variables

The following variables are not automatically set by the shell, although many of them can influence the shell’s behavior. They are typically used in your .profile file, where you can define them to suit your needs. Variables can be assigned values by issuing commands of the form:

variable=value

This list includes the type of value expected when defining these variables.

Variable expression	Description
CDPATH= dirs	Directories searched by cd ; allows shortcuts in changing directories; unset by default.
COLUMNS= n	Screen’s column width; used in line edit modes and select lists.
COMPREPLY=( words ...)	Array variable from which Bash reads the possible completions generated by a completion function.
EDITOR= file	Pathname of line-edit mode to turn on (can end in emacs or vi); used when VISUAL is not set.
EMACS	If the value starts with t, Bash assumes it’s running in an Emacs buffer and disables line editing.
ENV= file	Name of script that gets executed at startup; useful for storing alias and function definitions. For example, ENV=$HOME/.bashrc.
FCEDIT= file	Editor used by fc command (default is /bin/ed).
FIGNORE= pattern	Colon-separated list of patterns describing filenames to ignore when doing filename completion.
GLOBIGNORE= patlist	Colon-separated list of patterns describing the set of filenames to ignore during pattern matching.
HISTCONTROL= list	Colon-separated list of values controlling how commands are saved in the history file. Recognized values are: ignoredups, ignorespace, ignoreboth ...