I like it, thanks :)

AFAICT, not really, looks line POSIX sh at a glance. Just don’t forget to : <<'EOF' instead of : <<EOF.

But : is arguably simpler than cat, one fewer fork/exec call plus no open(2) on /dev/null.

C89, AKA ANSI C famously only supports /* */, having // as a cross-pollinated idea from C++.

No notepad.exe, nvi: 'a,s/^/# /.

I use this only when developing, mostly while debugging. IIRC I’ve never commited code like this.