bash Cookbook

set Options

The options in set Options can be turned on with the set -arg command. They are all initially off except where noted. Full names, where listed, are arguments to set that can be used with set -o. The full names braceexpand, histexpand, history, keyword, and onecmd are not available in versions of bash prior to 2.0. Also, in those versions, hashing is switched with -d.

Table A-6. set options

Option	Full name (-o)	Meaning
-a	allexport	Export all subsequently defined or modified variables.
-B	braceexpand	The shell performs brace expansion. This is on by default.
-b	notify	Report the status of terminating background jobs immediately.
-C	noclobber	Don’t allow redirection to overwrite existing files.
-E	errtrace	Any trap on ERR is inherited by shell functions, command substitutions, and commands executed in a subshell environment.
-e	errexit	Exit the shell when a simple command exits with nonzero status. A simple command is a command not part of a while, until, or if; nor part of a && or || list; nor a command whose return value is inverted by !.
	emacs	Use Emacs-style command-line editing.
-f	noglob	Disable pathname expansion.
-H	histexpand	Enable ! style history substitution. On by default in an interactive shell.
	history	Enable command history. On by default in interactive shells.
-h	hashall	Enable the hashing of commands.
	ignoreeof	Disallow Ctrl-D to exit the shell.
-k	keyword	All arguments in the form of assignment statements are placed in the environment for ...