1 $ \textbf{cat .hg/hgrc}

2 [hooks]

3 pretxncommit.whitespace = hg export tip | (! grep -qP '^\textbackslash{}+.*[ \textbackslash{}t]$')

4 $ \textbf{echo 'a ' > a}

5 $ \textbf{hg commit -A -m 'test with trailing whitespace'}

6 adding a

7 abort: pretxncommit.whitespace hook exited with status 1

8 transaction abort!

9 rollback completed

10 $ \textbf{echo 'a' > a}

11 $ \textbf{hg commit -A -m 'drop trailing whitespace and try again'}