Fix "add-apt-repository: command not found" on Debian

The error

You run add-apt-repository and the shell says the command is not found.

The command comes with the package software-properties-common, which Debian does not always install.

Solution 1: Install the package

1. Open a terminal (Ctrl + Alt + T), or connect by SSH.
2. Update the package list:

sudo apt update

Optionally upgrade the system:

sudo apt upgrade -y

1. Install the package:

sudo apt install software-properties-common

1. Check that the command now works:

add-apt-repository --help

Solution 2: Manual install

If the first solution does not help:

1. Install the Python package:

sudo apt install python3-software-properties

1. Create a link so the command is found. Check first that the file path exists on your system:

sudo ln -s /usr/lib/python3/dist-packages/softwareproperties/ppa.py /usr/bin/add-apt-repository

1. Add a repository. For example, the WineHQ repository:

sudo add-apt-repository "deb https://dl.winehq.org/wine-builds/debian $(lsb_release -cs) main"

To remove a PPA again, use ppa-purge (install it with sudo apt install ppa-purge):

sudo ppa-purge ppa:<ppa_name>

If you still have problems

• Check the spelling of the commands.
• You need a working internet connection to add repositories.
• Debian does not use Ubuntu PPAs in most cases. For Debian, add a repository line or a signed source file instead, as the project of the software advises.
• Read the documentation of the repository you add.

Quick recap

• Install software-properties-common.
• Run add-apt-repository --help to test.
• Use the manual link only if the package does not help.