Different Shells

First, the UNIX OS used Bourne shell.Later many were introduced for different flavors of UNIX/Linux.

Some of them..

• Sh       -- Bourne Shell
• Csh     -- C Shell
• Ksh     -- Korn Shell
• Tcsh    -- enhanced C Shell
• Bash   -- GNU Bourne Again Shell
• Zsh     -- extension to Bash, Ksh and Tcsh
• Pdksh  -- extension to KSH

The Syntax of all the Shells  is 95% similar.

We will discuss in further posts , the Bash shell programming, as it is the most common one.

Whenever we type a command on terminal window, the shell will execute immediately.
To check the shell we are using, type the command

echo $SHELL

And to check its version.

bash --version

Note: In Linux, the filenames are case-sensitive. Means, hello.txt and Hello.txt are two different files, this is not the case in Windows.