Why We Need Shell Scripting

Shell is a software program that acts as a mediator between the kernel and the user. It reads the commands and interrupts by sending requests to execute a program. So, the shell is known as a command interpreter.

It contains almost 100 system calls. It tells the kernel to carry out various tasks for the program. These tasks are as follows −

• Opening a file.

• Writing a file.

• Obtaining information about a file.

• Executing programs.

• Terminating a process.

• Changing the priority of processes.

• Getting the time and date.

Need of shell scripting

Let us see the reasons for using shell scripts which are given below −

• Shell helps in doing work which is repetitive in nature. For example: When executing a bunch of commands, often, shells can take all these commands directly from a stored file and execute it, instead of writing them again every time.

• They are used to get routine backups by admins.

• They are easier to write and debug than other programming languages like C or C++.

• We can transfer the shell script to other UNIX and similar operating systems and execute.

• Shell scripts are also used to monitor systems regularly.

Now let us see different shells used in different operating systems, which are as follows −

The shells used on Linux operating system are as follows −

• The Korn Shell,

• Bourne-Again Shell,

• Tcsh

The shells used on UNIX operating system are as follows −

• The Korn Shell

• The C Shell

• Bourne-Again Shell

The shells used on Windows operating system are as follows −

• Aston Shell

• Window Blinds

• Xoblite