cd 

Synatx: cd Name_Of_Directory

This command is used for changing directories. Type ‘cd’ command followed by the name of a directory for accessing that directory.
clear Used for clearing the screen of console.
df Used for checking disk space.
df -h Give an easily readable version of the output for the disk space
df –h –T Lists disk space including filesystem
finger Tells who is on the system. It can also give detailed information about who has access the computer.
finger name_of_user_accout Gives information on a certain user account.
logout Used for logging out from a particular user session in a system.
man name_of_command It pulls information about a particular Linux command. man –k followed by a certain word will give the list of all the commands containing that particular word.
more Used for reading the contents of a file. Just type this command followed by the name of file.
passwd Used for changing the password. Type this command and press enter and it will prompt you to change password.
pwd Type pwd and hit enter, it will tell you the name of the directory in which you are currently working.
nano Used for opening a text editor and editing files. Type the command and press enter and it will open a text editor. 

Type this command followed by the name of file for its editing.