Thanks for the Pdf Merging Online . ls and it common flags. ls lists the contents of the current directory. Using the -a flag lists all the contents, including hidden files. Using -l lists the detailed view, including info about permissions and owenership. cd. Used to change to a directory. Using cd ~ and cd without any arguments takes you to your home directory. Using cd / takes you to root cd .. takes you one level back. cp [source] [destination]. Used to copy files. Use the -r flag to copy directories. mv [source] [destination]. Used to move files. rm [name]. Used to remove files. Use -r flag to remove directories. Use with caution as it cannot be reversed. pwd. Displays the present working directory. mkdir and touch. Used to create directories and files respectively. cat. Displays the contents of a file. head and tail. Displays the first and last 10 lines of a file. Use the -n flag to specify the number of lines. Hope this helps.