Add --debugger global option With this option, hg will drop into the Python debugger on execution. Running 'continue' will execute normally, and the debugger will be reinvoked if an exception is raised.

#!/bin/sh

hg init
echo "[hooks]" > .hg/hgrc
echo 'precommit = echo precommit hook' >> .hg/hgrc
echo 'commit = echo commit hook: $NODE' >> .hg/hgrc
echo a > a
hg add a
hg commit -m "test" -d "0 0"