I used to work at a place where their mission critical software was running on ancient HP-UX boxes which we feared to turn off because we didn't know if they would turn back on. My job was to port this software to modern Ubuntu VMs. Once I was done, we had a celebration in which we turned off the HP-UX boxes forever... except of course there was a bug in my version, so we soon had to turn them back on while I worked on a fix.
To everybody's surprise, the machines did turn back on, but they couldn't connect to the network because a few configuration files were wrong. To our dismay, after we tried to use Vi to edit the first one, we discovered that the ESC key did not work anymore, and we were stuck in edit mode forever! We had to reboot the machine, which takes about an hour on these old machines.
And then of course I configured the files using Ed and saved the day! Surprisingly, I was the youngest programmer there and I was the only one who knew how to use it.
To everybody's surprise, the machines did turn back on, but they couldn't connect to the network because a few configuration files were wrong. To our dismay, after we tried to use Vi to edit the first one, we discovered that the ESC key did not work anymore, and we were stuck in edit mode forever! We had to reboot the machine, which takes about an hour on these old machines.
And then of course I configured the files using Ed and saved the day! Surprisingly, I was the youngest programmer there and I was the only one who knew how to use it.