I'm high school I attended a summer programming program where all of the computers we used were CLI Unix boxes. No GUI, no Windows XP. Just the command line and you. Learned quite a bit there, from basic C++ to very simple shell scripting.
I liked making my terminal environment black with lime green text a la The Matrix because it made me feel like a h4x0r.
Green on black is easy on the eyes. I used to rock an amber on black monitor on my 486/33 486 DX 66 (I upgraded the CPU). It was full SCSI, coax networking, dial-up modem, and Red Hat (Halloween). The disc came with either a book or a magazine. It's been a minute.
I still have the machine in storage. Fully wrapped in cellophane.
EDIT: When I finally shut her down, her final uptime was a little over 2300 days. We were moving so down she went.