Adjusting Shell Behavior Using set, shopt, and Environment Variables
This section combines Table A-5, set Options, and shopt options and provides a quick way to look for what you can configure and which of the three mechanisms you use to configure it. The options are loosely grouped according to function or purpose, but it’s worthwhile to scan the entire table to get an overall sense of what you can configure.
The “Set option” column contains the options that can be turned on
-arg command. All are initially off except
where noted. Items in the “Set full name” column, 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
The “Shopt option” column shows the options set with
arg. Versions of bash
prior to 2.0 had environment variables to perform some of these settings.
Setting them equated to
shopt -s. The
variables (and corresponding shopt options) were:
allow_null_glob_expansion (nullglob), cdable_vars
(cdable_vars), command_oriented_history (cmdhist), glob_dot_filenames
(dotglob), no_exit_on_failed_exec (execfail). These variables no
are not available in versions of bash prior to
The “Environment variable” column lists environment variables that affect bash configuration ...