7.3 How can I tell what packages are already installed on a Debian system?
To learn the status of all the packages installed on a Debian system, execute
the command
dpkg --list
This prints out a one-line summary for each package, giving a 2-letter status
symbol (explained in the header), the package name, the version which is
installed, and a brief description.
To learn the status of packages whose names match the string any pattern
beginning with "foo" by executing the command:
dpkg --list 'foo*'
To get a more verbose report for a particular package, execute the command:
dpkg --status packagename
