About Terminal Problem

Solution 1:

This is just an informational message telling you that in case you want to run a command with root user privileges, you have to use sudo.

Once you ran your first sudo command, this information will no longer appear.

If you don't know what sudo or "root user privileges" are, you probably don't need that at all yet. In case you're still curious, you might start reading about it here though.

To get rid of the message, simply run a sudo command like this:

sudo echo "Hello world"

It will ask you for your account password and then print the string "Hello world" to the terminal as root - which has no real use, but is enough for this case.