After logging into linux whatever you see is bash shell where you can issue commands.
I am just listing out basics commands here which can be used in exam. More commands will follow.
ls -> list content
ls -l -> list content in long listing format
alias -> display all aliases for current user
exit -> log out from the system
cd .. -> change to parent directory
cd - -> change to previous directory
cd -> change to home directory
ps -> display process status of current terminal
ps -l -> display process status of current terminal in Ctrl+c -> cancel/quit process
Ctrl+r -> search command
Ctrl+l -> clear screen
Ctrl+d -> log out
Ctrl+Alt+Delete -> reboot