See What Version of a Package Is Installed on Ubuntu

The package management system on Ubuntu makes it extremely simple to install and remove packages, but sometimes it’s important to figure out what version of a particular package that you actually have installed.

The apt-get utilities are simply a front-end to the debian dpkg utility, which actually does the real work. You can use this utility to figure out what version is installed.

    dpkg -s <packagename>

Here’s an example, where I was trying to figure out what version of Ruby I had installed on my system:

    geek@ubuntuServ:~$ dpkg -s ruby1.8

    Package: ruby1.8
    Status: install ok installed
    Priority: optional
    Section: interpreters
    Installed-Size: 272
    Maintainer: Ubuntu Core Developers <ubuntu-devel@lists.ubuntu.com>
    Architecture: i386
    Version: 1.8.4-5ubuntu1.2
    Depends: libc6 (>= 2.4-1), libruby1.8 (>= 1.8.4)
    Suggests: ruby1.8-examples, rdoc1.8, ri1.8
    Description: Interpreter of object-oriented scripting language Ruby 1.8
    Ruby is the interpreted scripting language for quick and easy
    object-oriented programming. It has many features to process text
    files and to do system management tasks (as in perl). It is simple,
    straight-forward, and extensible.
    .
    This package provides version 1.8 series of Ruby.
    .
    On Debian, Ruby 1.8 is provided as separate packages. You can get
    full Ruby 1.8 distribution by installing following packages.
    .
    ruby1.8 ruby1.8-dev ri1.8 rdoc1.8 irb1.8 ruby1.8-elisp
    ruby1.8-examples libdbm-ruby1.8 libgdbm-ruby1.8 libtcltk-ruby1.8
    libopenssl-ruby1.8 libreadline-ruby1.8
    Original-Maintainer: akira yamada <akira@debian.org>

You can see that I’ve got version 1.8.4 installed.