shellcheck recently added SC2330 checking for this. "which" is non-standard, and
not guaranteed by POSIX to have a meaningful exit status, while "command -v" is
specified by POSIX: https://stackoverflow.com/q/592620
On most platforms (according to shellcheck), you can't pass two
arguments in a shebang. I.e. on Debian you get:
/usr/bin/env: ‘bash -e’: No such file or directory
