I thought I was all clever because I figured out a good technique of making configuration files executable with #!. But apparently I was not so clever.

On FreeBSD I got this working nicely:

#!/usr/bin/env paster exe serve

The exe told paster that it should expect the shebang setup (config file follows, etc). And while putting paster itself as the command didn't work, /usr/bin/env parsed everything nicely for me (and since paster itself uses a shebang line to be executable, only /usr/bin/env was willing to recursively interpret that).

paster would then end up seeing an argv like ['paster', 'exe', 'serve', config_file, extra_args...] where extra_args were any arguments you passed on the command line. The environmental variable _ would be set to config_file.

Usually something that seems sensible on FreeBSD will work on Linux; in comparison to BSD tools, the GNU tools (standard on Linux) generally favor sensibility over backward compatibility, and FreeBSD seems very sensible in this case. I could only expect more sensibility on Linux, right?

Sadly, no. /usr/bin/env parses that as a request to run "paster exe serve" -- i.e., a file with embedded spaces. Sigh. It does still set _, and passes extra arguments. But I still want to know when I'm in a shebang environment, so paster can respond accordingly, and I'm not sure how to detect that. When environ['_'] != sys.argv[0]? Is that reliable? Is there another way to detect this? Any hints for MacOS (like FreeBSD?) and/or Solaris (like stupid Linux?)