How do I change directories from the command line? [duplicate]

iBelieve's answer covers almost everything, but alternatively you can type

cd ~/Desktop/

the ~/ stands for /home/$USER/ or $HOME/

To answer your question mentioned in the quoted article:

The directory format is like this:

/
    home
        <username>
            Desktop
            Documents
            ...

so your command should be

cd /home/$USER/Desktop

To learn the directory structure, I'd suggest opening up the Home Folder app from the launcher on the left, and going to Computer and just exploring for a while. You won't be able to break anything outside of your home folder.

Because I haven't seen it mentioned yet, it should be noted that all directory names in Ubuntu (Linux) are case-sensitive. So even if you were in your correct home directory, executing a cd desktop should and will fail. If you look at @iBelieve's post, you can see that the Desktop directory starts with a capital 'D'. To get there, you will need to specify the correct case.

cd Desktop

To help you in the future, take a look at this Ubuntu help wiki page on using the terminal.

The following bash builtin commands are equivalent and they change the current working directory to your Desktop directory from your user home directory:

cd ~/Desktop               # my favorite

cd ~; cd Desktop

cd ~ && cd Desktop

cd $HOME/Desktop

cd /home/$USER/Desktop

cd /home/username/Desktop  # where 'username' is your user name

cd $CDPATH && cd Desktop

cd `locate -b '\Desktop'`

cd $(locate -b '\Desktop')