The good old CLI
A friend of mine went to an interview a couple of days ago. Some of the questions were about how to deal with various tech support problems he would be facing. When he suggested that to solve one of them he would use the CLI, the interviewer got very excited and practically offered him the job on the spot. He made such an impression that they are going to pay him the salary they advertised, althoug he did have to push a little to get that.
I am a coder, not a techie, and in recent years have come to rely on tech support to solve my problems faster than figuring them out myself (my employer is quite insistent about that). But I have a couple of copies of DR DOS 6 that I keep in the loft, despite all the clear-outs that have seen me throw out other software. Don't worry if you don't know what that is, it's getting to be quite an elite group who do.