As mentioned above, the shell is a scripting language, so there must be an interpreter to execute the scripts.
The common shell scripting interpreters on Unix/linux include bash, sh, csh, Ksh, and so on, which are used to call them a shell. We often say that there are many kinds of shells, actually speaking of shell script interpreter.
Bash
Bash is the default shell for the Linux standard, and this tutorial is based on bash. The bash was completed by Brian Fox and Chet Ramey, a bourneagain shell abbreviation with 40 internal commands.
Linux uses it as the default shell because it has features such as the following:
You can use the functions of doskey like DOS to view and quickly enter and modify commands with the arrow keys.
A command that begins with a string is automatically given by finding a match.
Contains its own Help function, you can just type help below the prompt to get related assistance.
SH
SH was developed by Steve Bourne and is the abbreviation for the Bourne Shell, which is the default shell of the UNIX standard.
Ash
The ash shell was written by Kenneth Almquist, a small shell that occupies the least system resources in Linux, and it contains only 24 internal commands, making it inconvenient to use.
CSH
CSH is a Linux-based kernel that consists of 47 authors, represented by William Joy, and has 52 internal commands. The shell is actually a shell that points to/bin/tcsh, which means that csh is actually tcsh.
Ksh
Ksh is an abbreviation for the Korn shell, written by Eric Gisin, with a total of 42 internal commands. The biggest advantage of the shell is that it is almost completely compatible with the ksh of the commercial distribution, so you can try out the commercial version of the performance without having to pay for the commercial version.
Note: BASH is the acronym for the Bourne Again shell, the default shell for the Linux standard, which is based on the Bourne shell and absorbs some of the features of the C shell and Korn shell. Bash is fully compatible with SH, meaning that scripts written in SH can be executed without modification in bash.
Shell Learning 2-several common shells
