Typo was added in Research Unix V5[0] and also present in V6[1]. It isn't in V7, my guess is that it was replaced by spell. I don't think it would be difficult

Typo was added in Research Unix V5[0] and also present in V6[1]. It isn't in V7, my guess is that it was replaced by spell. I don't think it would be difficult to get it compile on a modern system. [0] https://github.com/dspinellis/unix-history-repo/blob/Research-V5-Snapshot-Development/usr/source/s2/typo.c https://github.com/dspinellis/unix-history-repo/blob/Researc... [1] https://github.com/dspinellis/unix-history-repo/blob/Research-V6-Snapshot-Development/usr/source/s2/typo.c https://github.com/dspinellis/unix-history-repo/blob/Researc...