Introduction to Shell

Computers understand the language of 0's and 1's called binary language, In the early days of computing, instructions are provided using binary language, which is difficult for all of us, to read and write. So in OSs, there is a special program called Shell. Shell accepts your instruction or commands in English and translates them into the computer's native binary language.

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What Shell Does do for us?

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Its environment provides for user interaction. Shell is a command language interpreter that executes commands read from the standard input device (keyboard) or from a file. Linux may use one of the most popular shells (In MS-DOS, the Shell name is COMMAND.COM which is also used for the same purpose, but it's not as powerful as our Linux Shells are!)

Generically speaking, a shell is any user interface to the UNIX operating system, i.e., any program that takes input from the user, translates it into instructions that the operating system can understand, and conveys the operating system's output back to the user.

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Types of Shells

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BASH ( Bourne-Again SHell ): Bash is a Unix shell and command language written by Brian Fox for the GNU Project as a free software replacement for the Bourne shell. Most common shell in Linux. It's a Freeware shell.

CSH (C SHell): The C shell is a Unix shell created by Bill Joy while he was a graduate student at the University of California, Berkeley in the late 1970s. The C shell's syntax and usage are very similar to the C programming language.

KSH (Korn SHell): KornShell ( ksh ) is a Unix shell that was developed by David Korn at Bell Labs in the early 1980s and announced at USENIX on July 14, 1983. 

Happy Exploring!