But now you're down in HelloWorld/src/helloworld . How do you get back up to
HelloWorld ? To go up just one level, you'd type this:
$ cd ..
Or to go up two levels, type this:
$ cd ../..
That's two periods (or dots), which is pronounced “up one.” One dot by itself
means the current directory, which isn't very useful with cd , but we will use
“.” with other commands—especially when copying files.
But now suppose you need to visit a directory that isn't just in the current
directory or up one. How do you get there? Suppose I'm somewhere completely
different, like /home/minecraft , and I want to go to /Users/andy/Desktop/code/HelloWorld .
I'd do something like this:
$ cd /Users/andy/Desktop/code/HelloWorld
The leading slash makes the difference. Earlier, when you typed cdsrc , the cd
command looked for src right under the current directory. But if instead you
typed cd /src it would look for a directory named src under a directory named
“ / ”—which we call the root .
Root is the topmost directory on your system. It's above your code, above
your Desktop, above everything. Somewhere under root are your home
directory and Desktop. In my case, that's /Users/andy/Desktop . I could get there
the slow way by typing this sequence of commands:
$ cd /
$ cd Users
$ cd andy
$ cd Desktop
But we'll see a much easier way in just a moment. And speaking of shortcuts,
you don't even need to spell out each directory name fully, like D-e-s-k-t-o-p.
On most systems, there's a nice keyboard shortcut to save you from typing
out long names—the Tab key. If you type in the first few letters of a long name
and then press the Tab key, it will autocomplete to the long name. Suppose
I'm in my code directory: