The Mac App store provides a nice, simple, graphical way to keep your Mac updated with the latest software, letting you know when system updates as well as Apple and third-party apps have a new update to be downloaded and installed.
If you don’t want to use the Mac App store, though, you can use the Terminal app along with some Terminal commands to do the same thing. When would you use this? Well, maybe when the Mac App store gets wonky, or if you’re not at the current Mac, and want to securely and remotely administer the Mac in question, that’s when.
It’s fairly simple. Here’s how.
Launch Terminal app from the Utilitles folder, found in the Applications folder. Once launched, type or paste the following:
sudo softwareupdate -l
You’ll need to enter the admin password here to let softwareupdate do its thing, which is essentially listing all available software updates for the Mac you’re working on, remotely or locally.
If you want to install everything on the list, equivalent to clicking the Update All button in the Mac App store, type or paste the command below:
sudo softwareupdate -i -a
If you’d rather install only one update at a time, type the following, but replace AppName with the name from the list you saw in step one, above.
sudo softwareupdate -i AppName
The caveat here is that the Terminal version of softwareupdate will only find and install system software updates, not third-party apps like the Mac App Store will. Of course, the Mac App Store can’t remotely update system software like this, either, so choose the tool best suited to your needs and specific tasks.
Source: OS X Daily