05: Getting from ‘A’ to ‘B’

  Wurm lab

We are in the home directory on the computer but we want to to work in the new learning_unix directory. To change directories in Unix, we use the cd command:

cd learning_unix
learner@:~/learning_unix$

Notice that on this system the command prompt has expanded to include our current directory. This doesn’t happen by default on all Unix systems, and you can configure what information appears as part of the command prompt (though we won’t cover that here).

Let’s make two new subdirectories and navigate into them:

learner@:learning_unix$ mkdir outer
learner@:learning_unix$ cd outer
learner@:outer$

learner@:outer$ mkdir inner
learner@:outer$ cd inner/
learner@:inner$

Remember that you can always find out where you are using pwd:

learner@:inner$ pwd
/home/learner/learning_unix/outer/inner

We created the two directories in separate steps, but it is possible to use the mkdir command in way to do this all in one step.

Like most Unix commands, mkdir supports command-line options which let you alter its behavior and functionality. Command-like options are - as the name suggests - optional arguments that are placed after the command name. They often take the form of single letters (following a dash). If we had used the -p option of the mkdir command we could have done this in one step instead of three above. E.g.

cd ~/learning_unix
mkdir -p outer/inner

You do not need to run it.

Note the spaces either side the -p!