Computer understand the language of 0’s(zeros) and 1’s(ones) called binary language. In early days of computing, instruction are provided using binary language, which is difficult for all of us, to read and write. So in O/s there is special program called Shell. Shell accepts your instruction or commands in English and translates it in to computers native binary language.
This is what Shell does for us
Your command (or) Shell Script —> Linux Shell —> Converted to Binary Language by Shell —> Now Linux Kernel understand your Request
You type your command and shell convert it is
$ Is 00101000
$ date —> Bash —> 10101011 —> Linux Kernel
$ time 01010010
It is environment provided for user interaction. Shell is a command language interpreter that executes commands and read from the standard input device or from a file.
Types of Linux Shells:
Shell is not part of system Kernel, but it uses the system kernel to executes programs, create files etc.
Several Shell available with Linux.
- BASH – Bourne-Again Shell
- CSH – C Shell
- KSH – Korn Shell
- TCSH – Advanced Version of C Shell