add users to switch user

[jatty]

I am new to linux 

I want to know about the su command  all details

[Raul1]

From the command line you can run:

man su

For most commands you will find a man page, also you can find man pages for different topics, if you want to search you can run:

apropos mytopic

it will show you all the man pages that have the string mytopic in the name or description

[Razique]

You can consult Linux manpages for that. To invoke it for a particular command use man <command>

The man man command will provide you with more information on how to browse the documentation.