How to Know Which Shell I am Using in Linux

Every Linux system has at least one shell where you can run commands, tasks, processes and shell scripts. Every Linux user is assigned a default shell. When a user opens terminal, they are logged into their default shell. Since there are multiple shells on most Linux systems, it may not be obvious which shell you are using. In this article, we will learn how to find out which shell you are using, how to list all available shells, and how to change your shell.

How to Know Which Shell I am Using in Linux

It is very easy to find out which shell you are using. Just open terminal and run either of the following commands.

# echo $0
OR
# echo $SHELL

$0 and $SHELL are system variables that store information about the shell the user is running. If you are using bash shell, you will see output like the following when you run the first command echo $0

-bash

You will see the following output when you run the second command echo $SHELL

/bin/bash

$0 stores the shell name and $SHELL stores the path to the shell.

If you want to list all shells installed on your system, or the ones you have access to, run the following command.

# cat /etc/shells

You will see the following kind of output depending on the shells installed on your system, as well as your access permissions.

# /etc/shells: valid login shells
/bin/sh
/bin/dash 
/bin/bash
/bin/rbash

If you want to change your default shell, use the chsh command, followed by -s or –shell option, followed by the full path of new shell you want to set as default. Here is the command to set your default shell as csh.

$ sudo chsh -s /bin/csh
OR
$ sudo chsh --shell /bin/csh

If you want to change the default shell of another user e.g. test_user, just add a space and mention it after the above commands, as shown.

$ sudo chsh -s /bin/csh test_user
OR
$ sudo chsh --shell /bin/csh test_user

In this article, we have learnt how to find out which shell you are using in Linux, how to list all available shells and how to switch shells. You can run these commands on almost all Linux systems, since they are universally available.

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