A shell script is a program that can be run in the Linux shell. Scripts are written in an interpreted language and consist of commands, functions and variables. These items are entered into a plaintext file that can then be run as a command.
Shell scripts in Linux are useful when you need to issue several commands to carry out a specific task. You don’t need to enter these command manually each time, one by one. Instead, you can create a script that contains all these commands.
Here is an example shell script:
Because, by default, most Linux systems use bash, shell scripts are most often written in the bash shell scripting language. Other shell scripting languages (tcsh, ksh) are similar to bash.