cd
$ cd Desktop/
cd takes a directory name as an argument, and switches into that directory.

cd ..
$ cd ..
$ cd ../..
To move up one directory, use cd ... Here, cd .. navigates up from jan/memory/ to jan/.

ls
$ ls
2014  2015  hardware.txt
ls lists all files and directories in the working directory

mkdir
$ mkdir media
mkdir takes in a directory name as an argument, and then creates a new directory in the current working directory. Here we used mkdir to create a new directory named media/.

pwd
$ pwd
/home/ccuser/workspace/blog
pwd prints the name of the working directory

rm
$ rm waterboy.txt
rm deletes files. Here we remove the file waterboy.txt from the file system.