How do you I find a list of softwares which are outdated and needs upgrade?

How do I find a list of packages that are outdated and need to be upgraded using aptitude?

I am using Ubuntu 10.04.

Solution 1:

update-manager (sitting in System -> Administration) should probably be your first port of call. Though if you want a command-line version:

sudo apt-get update
sudo apt-get dist-upgrade

aptitude and synaptic can also tell you.

Solution 2:

Another way to achive that from the command line is that of apt-show-versions.
The man page states:

apt-show-versions parses the dpkg status file and the APT lists for the installed and available package versions and distribution and shows upgrade options within the specific distribution of the selected package.

Once you've installed the package:

$ sudo apt-get install apt-show-versions

the only thing you have to do is:

$ sudo apt-show-versions -u

Hope that helps