MS Edit vs Edlin
My brother worked for a bank before retiring. During the '90s, he would sometimes have to demonstrate something on another department's PC (running some variant of MS-DOS and 16-bit Windows). I was visiting him one evening and he explained what he was going to demonstrate the next day, which involved editing a text file through the command line (it may have been CONFIG.SYS or AUTOEXEC.BAT). He was reasonably familiar with the MS-DOS commands and EDIT, having a PC at home in those "pre-internet" days. However, I warned him that older versions of MS-DOS wouldn't have EDIT available - he'd have to use EDLIN instead. I gave him a quick tutorial on the basics.
Turns out that he did in fact have to revert to EDLIN. Thereafter, he was held in awe as some sort of programming guru by his banking colleagues.
Biting the hand that feeds IT
