What is Bash
Bash is a program (toolbox) used to interact between user and operating system.
The BASH acronym is for the ‘Bourne-Again SHell’. Bash is one of many shells, or command language interpreters, in Unix system.
I called bash a “toolbox”, because it contains large variety of shell tools, for example, tools for read files, calculate math operations, control devices…
The main difference between bash and any other program is that bash was not created to process certain task. Bash was developed to take commands from user using the text-based interface.
One of the advantages of bash is that users can put list of commands to a one (script) and execute these commands from file.
Most of bash scripts have ‘.sh’ extension, for example: script.sh. Linux is an extensionless system, but it is good practice to add .sh extension.