Hey folks, I've noticed some surprising behaviour from cmp(1) when using the '-s' flag.
It appears that cmp -s is ignoring the byte offset arguments I'm giving it. I don't want to waste time babbling, so here's an example snippet to show what I'm talking about: #!/bin/sh echo 'my line' > /tmp/1.txt echo 'my other line' >> /tmp/1.txt echo 'same same' >> /tmp/1.txt echo 'my differnt line' > /tmp/2.txt echo 'my other different line' >> /tmp/2.txt echo 'same same' >> /tmp/2.txt # Determine byte offsets (we only want to compare lines >= 3) offset1="$(head -2 /tmp/1.txt | wc -c)" offset2="$(head -2 /tmp/2.txt | wc -c)" # Compare files and show exit code cmp /tmp/1.txt /tmp/2.txt "$offset1" "$offset2" printf '\nReturn code = %s\n' "$?" cmp -s /tmp/1.txt /tmp/2.txt "$offset1" "$offset2" printf '\nReturn code with "-s" = %s\n' "$?" As you can see, 'cmp -s' returns an exit code of '1', unlike cmp without the '-s' which returns '0'. Not sure what to make of this, I noticed this same behaviour on DragonflyBSD and FreeBSD, so maybe I'm just missing something obvious. This certainly caused some frustration before I figured out what was going on. Regards, Jordan
