When I was trying to setup an Ark Survival server on Ubuntu 16.04 following a guide published at Linode.com, I encountered the following error message when I ran the command "apt-get install steamcmd"

Unable to locate package steamcmd

That's kind of a big deal because the steamcmd package is needed to run an Ark Survival server.

Solution

I found the solution at askubuntu.com, which was to open up the /etc/apt/sources.list file and add the multiverse repository to it.

I'll show you the original and edited file contents so that you can see the edits I made.

The original contents of /etc/apt/sources.list looked like this:

deb archive.ubuntu.com/ubuntu xenial main restricted universe
deb archive.ubuntu.com/ubuntu xenial-updates main restricted universe
deb security.ubuntu.com/ubuntu xenial-security main restricted universe multiverse
deb archive.canonical.com/ubuntu xenial partner

And after adding the multiverse repository, my /etc/apt/sources.list file looked like this:

deb archive.ubuntu.com/ubuntu xenial main restricted universe multiverse
deb archive.ubuntu.com/ubuntu xenial-updates main restricted universe multiverse
deb security.ubuntu.com/ubuntu xenial-security main restricted universe multiverse
deb archive.canonical.com/ubuntu xenial partner

Then I ran the following to let Ubuntu know that I want to be able to get packages for the i386 architechure:

sudo dpkg --add-architecture i386

And then I ran the following to refresh the package information:

apt update

Then I was finally able to install steamcmd with the following command:

apt-get install steamcmd

It Worked!

Now steamcmd was installed and I was able to move on with the rest of the Ark Survival server installation.