What are the primary differences between shells? [closed]

Question

I was recently unable to answer what the differences between the fish shell and the bash shell were. Some of my questions deal with --> How come bash uses .bashrc and fish doesn't? I would really appreciate it if someone could shine some light on the subject. Note: This question doesn't just pertain to fish and bash rather it pertains to most shells alike.

Answer 1

The different shells support different commands and syntaxes. While the commonly used ones are somewhat compatible with the Bourne shell (predecessor to bash, the POSIX shell standard, and many other shells), they do vary. In particular, bash adds a lot of features not available in those other shells.

"bash" is a contraction of "Bourne again shell", a reference to the shell it was intended to supercede.

How come bash uses .bashrc and fish doesn't?

Because .bashrc is specific to bash. Most people use bash as their interactive shell, even if they use a different shell for executing scripts. Using .bashrc to set up your bash interactive environment allows you to put things in there that will only work on bash.

An alternative to .bashrc which is not bash-specific is .profile. The commands in .profile are intended to be used for any shell used interactively (the concept of .profile originated with the Bourne shell).

Note that .bashrc is read by non-login shells (eg subshells of your login shell) whereas .profile isn't.