[adduser student] to create a user named ‘student’
[passwd student] to change the password for user named ‘student’
[man command] to Show command details in brief
[what command] what is the command actually
[where command] location of the command
[which command] to Show exactly from where the command runs
[date] to show date
[cd directory] to change to the directory
[ls -a directory] to show hidden files
[ls -l directory] to show files of the directory
[touch file] to make a file
[cat file] to read the file
[mkdir directory] to make a directory
[who] to show who are logged in which terminals.
[cp source destination] to copy a source file to its destination directory.
[mv ] to move a source file to its destination directory.
[rm -i file] to remove a file
[rm -r directory] to remove directory