prefix hook env var names with HG_.
old names are still provided, but doc says they deprecated.
#!/bin/sh
hg init
echo 123 > a
echo 123 > c
hg add a c
hg commit -m "first" -d "0 0" a c
echo 123 > b
echo %% should show b unknown
hg status
echo 12 > c
echo %% should show b unknown and c modified
hg status
hg add b
echo %% should show b added and c modified
hg status
hg rm a
echo %% should show a removed, b added and c modified
hg status
hg revert a
echo %% should show b added and c modified
hg status
hg revert b
echo %% should show b unknown and c modified
hg status
hg revert c
echo %% should show b unknown
hg status
echo %% should show a b and c
ls
true