List all installed apt packages in Linux

To list all the installed apt in linux you can use apt list --installed.

Combining with grep

A great way to make this command more powerful is to combine it with grep

apt list --installed | grep gcalcli

Results in:

WARNING: apt does not have a stable CLI interface. Use with caution in scripts.

gcalcli/bionic,bionic,now 4.0.0~a3-1 all [installed]

Entering this command will list all packages which contain the text gcalcli