$ cat .hg/hgrc [hooks] pretxncommit.whitespace = hg export tip | (! egrep -q '^\+.*[ \t]$') $ echo 'a ' > a $ hg commit -A -m 'test with trailing whitespace' adding a transaction abort! rollback completed abort: pretxncommit.whitespace hook exited with status 1 $ echo 'a' > a $ hg commit -A -m 'drop trailing whitespace and try again'