Expand description
shebang_has_executable — every file that starts with #!
must have the Unix +x bit set.
The inverse of executable_has_shebang: catches scripts that
were committed with a shebang but where the executable bit
was never set (or got clobbered by git add --chmod=-x,
cp, a tarball round-trip, etc.). Running them requires
bash script.sh instead of ./script.sh, which is usually
not the author’s intent.
Non-Unix platforms: rule is a no-op. No fix op — chmod
auto-apply is deferred to a later release (see ROADMAP).