Change grep -e to grep --all We want to reserve -e for future use and grep compatibility. I've changed every-match to all out of a general preference for shorter long option names where short options don't exist.

#!/bin/sh

hg init
echo a > a
hg add a
hg commit -m "test" -d "0 0"
hg history
hg tag -d "0 0" "bleah" 
hg history

echo foo >> .hgtags
hg tag -d "0 0" "bleah2" || echo "failed"