$ \textbf{cat check_bug_id}
#!/bin/sh
# check that a commit comment mentions a numeric bug id
hg log -r $1 --template \{desc\} | grep -q "\textbackslash{}<bug *[0-9]"
$ \textbf{echo 'pretxncommit.bug_id_required = ./check_bug_id $HG_NODE' >> .hg/hgrc}
$ \textbf{echo a >> a}
$ \textbf{hg commit -m 'i am not mentioning a bug id'}
abort: pretxncommit.bug_id_required hook exited with status 1
transaction abort!
rollback completed
$ \textbf{hg commit -m 'i refer you to bug 666'}
committed