The-Unix-Shell-Teaching-Notes

3.10 Reproduce a folder structure

You’re starting a new experiment and would like to duplicate the directory structure from your previous experiment so you can add new data.

Assume that the previous experiment is in a folder called 2016-05-18, which contains a data folder that in turn contains folders named raw and processed that contain data files. The goal is to copy the folder structure of the 2016-05-18 folder into a folder called 2016-05-20 so that your final directory structure looks like this:

2016-05-20/
└── data
├── processed
└── raw

Which of the following set of commands would achieve this objective? What would the other commands do?

$ mkdir 2016-05-20
$ mkdir 2016-05-20/data
$ mkdir 2016-05-20/data/processed
$ mkdir 2016-05-20/data/raw

$ mkdir 2016-05-20
$ cd 2016-05-20
$ mkdir data
$ cd data
$ mkdir raw processed

$ mkdir 2016-05-20/data/raw
$ mkdir 2016-05-20/data/processed

$ mkdir -p 2016-05-20/data/raw
$ mkdir -p 2016-05-20/data/processed

$ mkdir 2016-05-20
$ cd 2016-05-20
$ mkdir data
$ mkdir raw processed

Solution

The first two sets of commands achieve this objective. The first set uses relative paths to create the top-level directory before the subdirectories. The third set of commands will give an error because the default behavior of mkdir won’t create a subdirectory of a non-existent directory: the intermediate level folders must be created first. The fourth set of commands achieve this objective. Remember, the -p option, followed by a path of one or more directories, will cause mkdir to create any intermediate subdirectories as required. The final set of commands generates the ‘raw’ and ‘processed’ directories at the same level as the ‘data’ directory.

Episode 4 Exercise 1