BASH - What is Shell ____(1)

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The shell is the interface that the user uses to communicate with the system.

Shell Types

• Bourne Shell (sh): Original and standard Unix shell.
• Bourne Again Shell (bash): Standard shell on linux, compatible with sh but with improvements. It also incorporates features from csh and ksh.
• Korn Shell (ksh): Also an enhancement to the bourne shell
• C Shell (csh): Brings in itself improvements to the features of the C language.

To find out which shell is being used on the system, just type echo $0 or ècho $SHELLortail /etc/passwd`:

machine@machine:~$ echo $0
output: bash

In case you want to install another shell, before installing it let's check:

sudo dpkg -l | grep ksh

If it doesn't return anything, it means that ksh is not installed, so do:

sudo apt-get install ksh

Typing again will see that it will return this time:

sudo dpkg -l | grep ksh

Now to use ksh, just type ksh in the terminal. To exit ksh just type exit.

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