"Some of bash's features are, in no particular order:
editing and completion; history and command re-entry; job control;
shell functions and aliases; arrays; arithmetic; ANSI C quoting;
tilde expansion; brace expansion; substring capabilities; indirect
variable expansion; expanded I/O capabilities; control of built-in
commands; help; directory stack; POSIX mode; internationalisation;
bash is the default shell on all popular Linux distributions.
For this reason, it's widely used, but rarely to anything like its
bash is, perhaps, the Linux program you use the most at work,
yet how much are you really getting out of it? If you would like to
enhance your productivity by reducing the amount of keystrokes you
type on a given day, this document is for you."