fish is a user friendly command line shell for UNIX-like operating systems
As a user friendly commandline shell intended mostly for interactive use, the fish shell has three high level goals. These are:
• Everything that can be done in other shell languages should be possible to do in fish, though fish may rely on external commands in doing so.
• Fish should be user friendly, but not at the expense of expressiveness. Most tradeoffs between power and ease of use can be avoided with careful design.
• Whenever possible without breaking the above goals, fish should follow the Posix syntax.