A long time ago, as a novice sysadmin, I spent some unhappy time fixing a broken Solaris server. The problem was fsck was in /usr/sbin, /usr was a mount point

A long time ago, as a novice sysadmin, I spent some unhappy time fixing a broken Solaris server. The problem was fsck was in /usr/sbin, /usr was a mount point on an external drive array that got its power yanked. Challenge: to boot you need to mount /usr, but first you have to fsck it using the binary in /usr/sbin ... After that I would make sure to have some working (static) binaries for rescue on every *nix system, tar at least, and on Solaris an extra /usr/sbin/fsck under the /usr mount point). You can fix a lot of things with tar, sed and netcat.