Learning the bash Shell, Second Edition

set Options

Table 2.6 lists the options that can be turned on with the set - arg command. All are 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 B-6. Options to set

Option	Full Name	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	errexit	Exit the shell when a simple command exits with non-zero status. A simple command is a command not part of a while, until, or if; or part of a && or || list; or 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	Disable the hashing of commands.
	ignoreeof	Disallow CTRL-D to exit the shell.
-k	keyword	Place keyword arguments in the environment for a command.
-m	monitor	Enable job control (on by default in interactive shells).
-n	noexec	Read commands and check syntax but do not ...