I am curious what your background or specialization is, but I can confirm the skills you learn from Linux, backups, and networking will be applicable now and in the future. The only thing they can do is help make you a better engineer.
Being able to do various forms of maths (e.g. geometry) has been a useful skill for literally millennia.
Being able to drive has been a useful skill for about a century. The number of people who need this skill has probably peaked in developed countries, but is rising globally.
A lot of basic computer and networking technologies have been around since the 70s or even earlier and the pace of change has slowed a lot since then.