∙ Working with files

How to create, delete, rename and copy files (and folders)

Contents

Learn more

We give some warnings on this page, but don’t be intimidated! Mistakes are only human, and you won’t be able to damage your computer through any of these commands.

To improve your skills in backing up, version control, and minimising risk in computing, look for our courses on Best Practices in Software Engineering.

Course materials

From this point forward, you will need to download the course materials; move this to a suitable folder, and unzip it.

If you are using GitBash on Windows, copy and run this command

git clone https://github.com/alleetanner/intro-to-command-line.git

In our terminal, use the command line to move into the course materials folder, command-line-files. When you run ls in this folder, you should see the list of contents looking like

example_files     sandpit    some_plays

Personally, I don’t find that clear to look at, so let’s use our first flag, running ls -l.

Questions

What do you think the -l is short for?
What extra information are you given?
Try some more flags and work out what they do: -s, -t, -r
And some flag combinations: -ls, -lrt

Info

Flags are also known as “options” - you will have to get used to this!
Flags start with a -, a dash.
Spoken, the command ls -l might be said “L S dash L”… but sometimes people say “minus”, or “hyphen” instead of “dash”. These all mean the same thing: the key to the left of the =+ key.

Copying

Let’s move into the folder called sandpit and play with some files. Firstly, let’s copy a file:

cp data1 data3

Here we are saying “copy the file called data1 to a new file called data3”. We now have two identical copies of the same file, only different by name.

Warning

The command line will overwrite files with no warning! If, for example, data3 already exists, the command cp data1 data3 would overwrite data3 with the contents of data1 - permanently deleting the contents of data3!
With great power comes great responsibility! :)

Deleting

Now let’s try to delete, or “remove”, the file we just made:

rm data3

Here we said “remove the file called data3”.

Warning

rm, “remove” is the same as delete. But without a recycle bin, undo, back button, or any other safety-nets.
rm, cp and mv commands all have the potential to cause permanent data loss!

Now let’s try copying, moving and removing folders. There are some folders in the sandpit to play with. Have a go at using cp and rm on there, and notice what it will and will not let you do. For folders that are not empty, we will need to use another flag:

cp -r folder_with_files_inside folder_copy

Here we asked the computer to “copy, recursively, this folder to that folder”. Empty folders can be copied, moved and removed, but you will need to use -r if there are items insides. -r is a common flag which we will use again later.

Info

Not all flags mean the same, when applied to other commands! -r does the same thing for cp and mv and rm, but don’t assume it does the same thing for all commands!

Try moving into the folder with files inside.

Question

Can you cp a file to the folder containing the one you are in?

Moving

Finally, let’s look at moving files.

mv data1 data4

Which means, “move the file called to data1 to a file called data4”. Move is essentially “rename” (although it is doing exactly the same as moving items in your graphical interface).

Warning

As such, if data4 already existed, it would be deleted by the command mv data1 data4! Be very careful with mv!
OK, that is my last warning for now :)

Exercise

Have a play in the sandpit, using cd, ls, mkdir and the file manipulation commands cp, rm and mv.

Exercise

Can you mv one file to more than one destination?
What happens if you give cp no destination?
Can you cp, but without being inside the folder it is located in?
Can you move a folder?
How does moving a file onto a folder behave?
Can you mv the folder you are actually in?