Bash Shell Options

A POSIX compliant shell can be configured with the set and unset builtins. To inspect the enabled options, use the $SHELLOPTS shell variable.

bash(1) expands on the set of configuration options. These options are set with the shopt builtins. To inspect the enabled options, use the $BASHOPTS shell variable.

Contents

  1. Bash Shell Options
    1. Compatibility Levels
    2. Extended Debugging Mode
    3. Window Size

Compatibility Levels

bash(1) 4 introduced compatibility levels, wherein the behavior of the shell are modified. 

shopt -e compat31

The modes available through the shopt builtin are:

A shell only has one compatibility level, so each mode is mutually exclusive.

From bash(1) 4.3+, use of the $BASH_COMPAT shell variable is preferred.

Extended Debugging Mode

extdebug

Window Size

If checkwinsize is enabled, bash(1) checks the window size after every (non-builtin) command. This triggers updates to the $LINES and $COLUMNS shell variables.

This is a sensible default for all interactive shells. 

[[ $DISPLAY ]] && shopt -s checkwinsize

CategoryRicottone