addaptrepository

Addaptrepository, commonly invoked as add-apt-repository, is a command-line utility for Debian-based Linux distributions that manage APT repositories. It is provided by the software-properties-common package and is widely used on Ubuntu and derivatives to simplify adding and removing repository entries, including personal package archives (PPAs). The tool writes new repository definitions to files under /etc/apt/sources.list.d and can import the repository’s GPG key to allow package verification.

The command accepts a repository specification in either PPA form or a standard APT source line. Examples include adding a PPA, such as add-apt-repository ppa:deadsnakes/ppa, or adding a conventional deb line like add-apt-repository "deb http://archive.ubuntu.com/ubuntu focal main universe". It also supports removing repositories with -r and can update the package list automatically with options like -u or --update, though users can also run sudo apt update manually after changes.

Usage and options are designed to be straightforward. Typical workflow involves adding the repository, possibly confirming key imports, and then refreshing the package index before installing software from the new source. The command is particularly convenient for enabling PPAs or third-party repositories that are not part of the distribution’s official sources.

Security and maintenance notes: only add repositories from trusted sources, as enabling new sources affects system security. After modifying repositories, run a package index update and install or upgrade packages as needed. If necessary, repositories can be removed cleanly with add-apt-repository -r.