Access Applications directory in Terminal

In the Terminal you can type the absolute path...

cd /Applications

to access applications installed for all users.

If you want to access the root folder (named "Macintosh HD", in your case), it called / in Mac OS X (and other UNIX variants).

And cd, meaning change directory, is used to navigate.

Alternatively, you can use the shortcut ⌘+⇧+G in the Finder and type...

/Applications

You do not need to type out the whole name. Tab-completion automatically adds the last letters. You can invoke tab-completion by pressing ⇥ while typing /Applications.

In terminal type:

cd /
cd Applications

Or you can just type:

cd /Applications

At this point, if you type pwd (print working directory) it should return /Applications

A great place to start with Terminal is http://linuxcommand.org/learning_the_shell.php even though it is aimed at Linux users

To navigate using the terminal you will use 2 commands; cd and ls.

To change directory you use cd. Ex: cd myfolder/anotherFolder.

You can type pwd to display the current directory you are in.

To list the content of a directory use ls. You can get more info about the content of a directory using ls -al.

You will notice that here are 2 directories which are always present wherever you list the content of a directory: . and ...

. is simply a reference to the current directory so typing cd ./somedir and cd somedir are equivalent.

.. is a reference to the parent directory. So using cd .. will move you back to the parent directory.

There are 2 ways to navigate. Either by using the full path or by using the relative path.

Let's say you are in /Users/user20378. If you want to get to /Applications you can either navigate there using the full path cd /Application or the relative path cd ../../Applications.

Depending on where you want to navigate the relative path can be more or less efficient than the full path.

Use tab while typing the name of a folder or a file to auto complete.