pacman. More information here


Remove a package and its deps not required by any other packages:

pacman -Rs package_name

Remove a package and its deps and all the packages that depend on the target package:

pacman -Rsc package_name

Search for already installed packages:

pacman -Qs string1 string2 ...

Search for package file names in remote packages:

pacman -Fs string1 string2 ...

Show extensive information about a given package:

pacman -Si package_name

Show information about a local package:

pacman -Qi package_name
pacman -Qii package_name (also list of backup files and their modification states)

Which remote package a file belongs to

pacman -Fo /path/to/file

All packages no longer required (orphans)

pacman -Qdt

List dependency tree

pactree package_name

Who needs a package

pactree -r package_name

Clean the package cache

pacman -Sc

Pacman fails signature verification

If encounter this while makepkg:

==> Verifying source file signatures with gpg...
linux-4.6.tar ... FAILED (unknown public key 79BE3E4300411886)
patch-4.6.3 ... FAILED (unknown public key 38DBBDC86092693E)

Because makepkg uses gpg and is unaware of the pacman’s keyring. Do this:

# run as root
gpg --list-keys

Receive the keys using pacman-key -r KEY_ID first, and then, add keyring /etc/pacman.d/gnupg/pubring.gpg to the end of ~/.gnupg/gpg.conf