Package managers can detect which packages were manually installed (at user or script explicit request) and which were implicitly installed as a prerequisite. When uninstalling the manually installed package, the prerequisite packages are often not auto-uninstalled. To recover the possibly significant amount of disk space (100’s of megabytes perhaps) from these now unused packages, an autoremove command is useful.

Pacman shows the auto-installed prerequisites with:

pacman -Qdtq

This can be piped into the Pacman remove command upon verifying the packages above are indeed OK to remove:

pacman -Qdtq | pacman -Rs -

The package cache can contain gigabytes no longer needed. The pacman cache is cleared by:

pacman -Sc

For systems using “apt” the equivalent commands are:

apt autoremove

apt autoclean