A classic story, of disaster averted by great ingenuity and the use of simple effective tools.
Unix Recovery Legend by Mario Wolczko
It was a quiet Wednesday afternoon. Wednesday, 1st October, 15:15 BST, to be precise, when Peter, an office-mate of mine, leaned away from his terminal and said to me, “Mario, I’m having a little trouble sending mail.” Knowing that msg was capable of confusing even the most capable of people, I sauntered over to his terminal to see what was wrong. A strange error message of the form (I forget the exact details) “cannot access /foo/bar for userid 147” had been issued by msg. My first thought was “Who’s userid 147?; the sender of the message, the destination, or what?” So I leant over to another terminal, already logged in, and typed
grep 147 /etc/passwd
only to receive the response
/etc/passwd: No such file or directory.
Instantly, I guessed that something was amiss
(As discussed many times on HN although I came across it recently at Danilo Bargen’s Stories From The Internet)