How to test if package is installed? [duplicate]

Solution 1:

You could use the output of dpkg -s <packagename> or dpkg-query -l <packagename>

in your script for the purpose.
Courtesy:https://stackoverflow.com/questions/1298066/check-if-a-package-is-installed-and-then-install-it-if-its-not

e.g.

#!/bin/sh

for P; do
    dpkg -s "$P" >/dev/null 2>&1 && {
        echo "$P is installed."
    } || {
        echo "$P is not installed."
    }
done

Usage: script.sh package1 package2 .... packageN

Courtesy:https://stackoverflow.com/a/10594734/749232