Add the SHEBANG to the first line of hook, like so:
#!/bin/sh
echo "executing post-commit"
exit 0
This had me stumped for a while as well and I saw that adding the shebang fixed it. In SVN world, while in *nix we have a “pre-commit” script and in Windows we had “pre-commit.bat” and SVN automatically picked up the bat file in Windows. Git doesn’t seem to pick up a pre-commit.bat ( or any hook ) and adding the shebang to the hook file worked.