At any given point of time after logging in, a user at a terminal will have a "current working directory". There is only one current directory for a user, but many users can be present at a directory at the same time. "Navigation" refers to moving between the directories.

The terminal is where you'll type the commands. An example of a command is "ls". Typing "ls", without the quotes at the terminal will list all the files in the current directory you are in, Every command has numerous options. For example, "ls -l" will list the files in the long listing format. "l" (el) is one of the options of the ls command. "a" is another option of "ls". Options can be combined. Example : "ls -la" or "ls -al" will list the files in the long listing format, and the listing will include the hidden files too (due to the option "a").

Some of the commands that you will be using frequently are listed here.

man - to go to the manual pages. "man cd" will open the manual pages of the command cd.

ls - to list files. "man ls" will give you a list of the options available with ls.

cd - to navigate between directories. "cd /var/" will take you to the directory /var. "cd .." will take you one directory up in the linux file system tree.

cat - to read a file. "cat myfile" will output the file at the terminal.

pwd - to print the current working directory.

mkdir - to create a new directory inside the current directory. "mkdir newdir" will create a new directory named newdir.

mv - i) to move a file from a directory to another; ii) to rename a file. "mv file1 file2" will rename file1 to file2. "mv file1 /home/tom/" will move the file file1 from the current directory to the directory /home/tom.

rm - to remove files. "rm file1" will delete a file file1 from the current directory, once you confirm that you really want to delete the file, by entering "y" when you're asked to confirm.

cp - to copy fles. "cp file1 /home/tom/" makes a copy of the file file1 in the directory /home/tom.

who - to list all the users currently logged into the server.

passwd - to change your password.

touch - creates a new file. "touch a" will create a new file called "a".