I actually almost submitted something in that vein once. I'd type
> ls | wc -l
and get
> bash: wc: command not found
As it turns out, I need Alt+1 to type a pipe character in my keyboard. If I'm not quick enough releasing the Alt key, I'll type Alt+Space instead of just Space, which inserts a Non-breaking space[1] in Mac. This character is not a space, and therefore it gave me a weird "command not found" error.
This lasted for months until I found out what the problem was - given that it was a combination of my keyboard settings and OS, finding the root of the error took quite some time. The hint? The "command not found" error had an extra space in front of the unknown command.
"My simple piece of code looks perfect and should work without problems. Yet it won't compile! Help!"
Answer:
"Try running `./mimic --reverse` on your source."