B.5 Options

These are options that can be turned on with the set -o command. All are initially off except where noted. Abbrevs, where listed, are arguments to set that can be used instead of the full set -o command (e.g., set -a is an abbreviation for set -o allexport). The abbreviations are actually backward-compatible Bourne shell options.

Option	Abbrev	Meaning
allexport	-a	Export all subsequently defined variables.
errexit	-e	Exit the shell when a command exits with non-0 status.
bgnice		Run all background jobs at decreased priority (on by default).
emacs		Use emacs-style command-line editing.
gmacs		Use emacs-style command-line editing, but with a slightly different meaning for [CTRL-T] (See Chapter 2, Command-line Editing).
ignoreeof		Disallow [CTRL-D] to exit the shell.
markdirs		Add / to all directory names generated from wildcard expansion.
monitor	-m	Enable job control (on by default).
noclobber		Don't allow > redirection to existing files.
noexec	-n	Read commands and check for syntax errors, but don't execute them.
noglob	-f	Disable wildcard expansion.
nolog		Disable command history.
nounset	-u	Treat undefined variables as errors, not as null.
privileged	-p	Script is running in suid mode.
trackall	-h	Substitute full pathnames for commands in alias expansions.
verbose	-v	Print commands (verbatim) before running them.
vi		Use vi-style command-line editing.
viraw		Use vi mode and have each keystroke take effect immediately.
xtrace	-x	Print commands (after expansions) before running them.