Ubuntu has updates every couple of days, while the GUI Update Manager is good at nagging my. I was wondering if there's a command line way to check for updates.
Answers for any recent Ubuntu releases would be great.
This will tell you if there are updates available:
sudo apt-get update sudo apt-get upgrade
Before actually installing anything, consider carefully what you're being offered and how the upgrades may affect your system.
I use Debian rather than Ubuntu, but I would be surprised if Ubuntu really had security updates daily. That said, you never know which day they will be available, so it pays to check often.
See here for a tutorial on Ubuntu's command-line tools for installing software. (Based on other pages from her site, I take it that Ubuntu now recommends GUI methods rather than apt-get.) I know that you asked for command-line methods, but you can also use Synaptic manually. That is, instead of waiting for the automatic check, just fire up Synaptic, let it update your sources and see if it tells you that there are upgrades. If you're not used to the command-line, that will probably be easier.
I have apticron running, which sends me an email each day that there are outstanding updates.