Remove some options from 'hg grep': -Z (we have -0 as in locate) -a (use "-r 0:tip" instead, or always grep all unless -r is given) -e (we have the PATTERN argument) -v (doesn't work, and this is more of a job for 'hg cat|grep') -s (we have -q/--quiet) -f (should be always enabled if -l used, or enable on -v/--verbose)

Is there an error message when trying to diff non-existing files?
not: No such file or directory
found: No such file or directory
Is there an error message when trying to add non-existing files?
not: No such file or directory
found: No such file or directory