Tuna is a type of fish so the joke is that they sound the same.
There was also the record You Can Tune a Piano, but You Can't Tuna Fish by REO Speedwagon, I had assumed that's what the tunefs man page was referencing as that was a best-selling record at around the time Unix was being developed.
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There was also the record You Can Tune a Piano, but You Can't Tuna Fish by REO Speedwagon, I had assumed that's what the tunefs man page was referencing as that was a best-selling record at around the time Unix was being developed.