Message3452

Jython's runner (sys.executable) is a .sh, or .bat file on Windows. On 
POSIX a .sh file cannot be used as a shebang line interpreter, meaning:

#!/path/to/jython

does not work

One partial workaround is to have distutils (and setuptools) change the 
interpreter to:

#!/usr/bin/env /path/to/jython

We're getting this workaround applied to both because it's dead simple 
and allows most scripts to work, but this solution has its own problem: 
it doesn't work when extra arguments to the interpreter are used. I.e. 
on various platforms (like Linux IIRC, and some others), this does not 
work:

#!/usr/bin/env /path/to/jython -S

There exists a similar issue on Windows for setuptools -- as setuptools 
installs scripts with an accompanying .exe file to facilitate easily 
running scripts on Windows as you would on POSIX. This helper .exe 
doesn't work for the same reason, because our sys.executable is a .bat.

The fullproof solution here is to make the runner a native executable on 
all platforms. This wouldn't be too bad to accomplish for Windows as we 
could just ship a precompiled .exe. 

However shipping pre-compiled executables for the various POSIX 
platforms would be a big pain. Having the Jython installer detect a 
compiler and compile one on the spot would also be a big pain, and 
basically creates a recommended dependency of a C compiler. We'd rather 
keep Jython's sole dependency the JRE.

JRuby and Groovy share this issue, though I've seen some JRuby tutorials 
recommend use of ruby's -S argument to run scripts, which totally avoids 
the issue. -S is a little like Python's -m but searches PATH instead of 
sys.path:

  -S              look for the script using PATH environment variable

MRI/YARV also have this option so it isn't too foreign to JRuby users.