If I were you, I'd forgo those instructions, and not bother with a PPA (unnecessary for icon themes), instead just placing the icon theme directories into '~/.icons/'; it's really that simple. Sometimes installation instructions overcomplicate matters, confusing people who aren't familiar with Linux. TBQH, I've probably been guilty of doing that myself.
Note that the following instructions don't verify the files in any way, which is what the gpg(1) step does (in a very thorough way).
So, what I would do is, install git(1) so you can work with Git repositories:
Clone the repository to the current directory:
Code: Select all
git clone 'https://github.com/PapirusDevelopmentTeam/papirus-icon-theme'
Copy the icon theme directories to your HOME:
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cp -r papirus-icon-theme/{Papirus{,-Light,-Dark},ePapirus{,-Dark}} ~/.icons/
If you want, you can now uninstall git(1):
Just ran those commands myself, and it worked fine. It's a nice theme.
Remember to remove that 'papirus-icon-theme' repository directory if you don't need it anymore.