Using Software Repos
Software repositories are a standard way that Linux machines provide robust, reliable tools in a fashion that can be maintained by the OS distributor. If you want to be sure that your software works, and that it's not infected with some kind of cryptovirus, it's a good idea to use them. Let's look at how:
Most major OS distributions have their own package manager - yum, pacman, and apt are but three. At WUR, we are aiming to support Ubuntu desktops, so this introduction will mostly cover apt and Symantic, but a lot of the concepts will be relatable.
For the total beginner on Ubuntu, you'll have access to Symantic by looking in the menus for 'Software'. Depending on your desktop, this could mean typing 'software' in the search bar, or finding it under System Tools. Here you can search for packages and install them, much like the App Stores found in Windows and Android. The advantage here is that everything you find is free (and often libre), and requires no accounts that can track you, or credits you have to purchase.
On the command line, apt is somewhat more powerful. It's a good idea to first do:
sudo apt-get update
Before anything - this will refresh your local cache of known packages up to that found on the remote servers (yum doesn't need this - it does it on any other step). You must use sudo to do this - you must elevate your privileges to be able to affect the machine more than just your user. This ensures that your normal processes cannot accidentally (or maliciously) write files to sensitive locations unless you explicitly allow it.
To update your machine, you can merely type:
sudo apt-get upgrade
And you will be presented with the list of packages that are behind the repos. You should update these. Another good one is:
sudo apt-get dist-upgrade
Which updates more critical packages (like your kernel) that can't be easily downgraded if there's a problem. Be more careful with this one, but it's usually not a huge issue.
To install something new, first find it. Try looking for it with:
apt-cache search mypackage
(no sudo needed - it's not writing anything) Hopefully you'll be able to find what you need. If not, try adjusting the parameters. Once you have it, you can merely:
sudo apt-get install mypackage
And it and all its prerequisites will be installed on your machine.
To remove packages, that's simply:
sudo apt-get remove mypackage
And your package will be removed. Any dependencies it has that aren't being relied on by other packages (or weren't manually installed) will also be removed. Sometimes, however, this doesn't happen, and you need:
sudo apt-get autoremove
To tidy up the excess.