Check installed packages from commandline
To check for installed packages from the command line, use the dpkg command with the --get-selections option. This returns all packages installed on your system (most likely a lot!). So it is best to use grep to narrow down the search results. For example, the following command lists all packages with “fire” in the package name:
dpkg --get-selections | grep fire
firefox install
firefox-3.0 install
firefox-3.0-branding install
firefox-3.0-dom-inspector install
firefox-dom-inspector install
mozilla-firefox-locale-en-gb install
An alternative which shows more information, including the exact version of the package and a description is the -l option. Because grep works with the output of the dpkg command, this will also include packages where the search term appears in the description, such as ufw on the last line in the output below because of “firewall”.
$ dpkg -l | grep fire
ii firefox 3.0.10+nobinonly-0ubuntu0.9.04.1 meta package for the popular mozilla web bro
ii firefox-3.0 3.0.10+nobinonly-0ubuntu0.9.04.1 safe and easy web browser from Mozilla
ii firefox-3.0-branding 3.0.10+nobinonly-0ubuntu0.9.04.1 Package that ships the firefox branding
ii firefox-3.0-dom-inspector 3.0.10+nobinonly-0ubuntu0.9.04.1 dummy upgrade package for firefox-3.0-dom-in
ii firefox-dom-inspector 3.0.10+nobinonly-0ubuntu0.9.04.1 meta package for firefox-dom-inspector
ii mozilla-firefox-locale-en-gb 2.0.0.7+1-0ubuntu4 Mozilla Firefox English language/region pack
ii ufw 0.27-0ubuntu2 program for managing a netfilter firewall
Using the above commands can be a faster and more efficient alternative to searching for installed packages in Synaptic.