a. Creating Directories

We now know how to explore files and directories, but how do we create them in the first place?

Step one: see where we are and what we already have

Let’s go back to our shell-lesson-data directory on the Desktop and use ls -F to see what it contains:

$ pwd

/Users/nelle/Desktop/shell-lesson-data

$ ls -F

creatures/  data/  molecules/  north-pacific-gyre/  notes.txt  pizza.cfg  solar.pdf  writing/

Create a directory

Let’s create a new directory called thesis using the command mkdir thesis (which has no output):

$ mkdir thesis

As you might guess from its name, mkdir means ‘make directory’. Since thesis is a relative path (i.e., does not have a leading slash, like /what/ever/thesis), the new directory is created in the current working directory:

$ ls -F

creatures/  data/  molecules/  north-pacific-gyre/  notes.txt  pizza.cfg
solar.pdf  thesis/  writing/

Since we’ve just created the thesis directory, there’s nothing in it yet:

$ ls -F thesis

Note that mkdir is not limited to creating single directories one at a time. The -p option allows mkdir to create a directory with nested subdirectories in a single operation:

$ mkdir -p project/data project/results

note

Two ways of doing the same thing

Using the shell to create a directory is no different than using a file explorer. If you open the current directory using your operating system’s graphical file explorer, the thesis directory will appear there too. While the shell and the file explorer are two different ways of interacting with the files, the files and directories themselves are the same.

note

Good names for files and directories

Complicated names of files and directories can make your life painful when working on the command line. Here we provide a few useful tips for the names of your files and directories.

  1. Don’t use spaces. Spaces can make a name more meaningful, but since spaces are used to separate arguments on the command line it is better to avoid them in names of files and directories. You can use - or _ instead (e.g. north-pacific-gyre/ rather than north pacific gyre/). To test this out, try typing mkdir north pacific gyreand see what directory (or directories!) are made when you check with ls -F.

  2. Don’t begin the name with - (dash). Commands treat names starting with - as options.

  3. Stick with letters, numbers, . (period or ‘full stop’), - (dash) and _ (underscore).

If you need to refer to names of files or directories that have spaces or other special characters, you should surround the name in quotes ("").