100 Useful Command-Line Utilities
by Oliver; 201477. shopt
shopt, for shell options, controls various togglable shell options, as its name suggests. You can see the options it controls by simply entering the command. For example, on my system:$ shopt cdable_vars off cdspell off checkhash off checkwinsize off cmdhist on compat31 off dotglob off . . .There's a discussion about shopt's histappend option in An Introduction to the Command-Line (on Unix-like systems) - history.
