If you’ve ever written a paper, then you know that the Tab key exists on a keyboard. This key is a lazy Terminal user’s best friend, because it acts as an autofiller for unique names. Say you want to open theWorldsLongestDatasetwiththeWorldsLongestName.dat. First, that name is really long. Second, there’s a lot of weird capitalization. Say that there are a few file names in the same directory that start with “the,” but none of them start with “theW.” Thus, you can type vi theW and hit the tab key. Suddenly, what you’ve typed is now vi theWorldsLongestDatasetwiththeWorldsLongestName.dat, and you can hit enter to view the file. The tab key can also be used to bring you to the next point of difference, in addition to finishing commands or program names. If I type just whi, then hit tab twice, the Terminal will list the two things that start with whi, which are the which and while commands. Thus, by then typing a c or l, and hitting tab once more, I will have the completed command. This is a great help if you know how a file name starts, but don’t remember its unique breaking point.