ls m <TAB><TAB><TAB>Then push the <TAB> key. Linux is going to beep a couple of times, but you keep pushing. You will now see every file in the directory that begins with the letter 'm'
ls mo <TAB>
cd /usr # this will take you to the /usr directory
ls -l # This will give you a more detailed view about the contents of your current directory, which happens to be the /usr # directory.