Re: exit status

Greg Ward wrote:
> Got any more compelling source than that?

The bash manpage corroborates:

     All builtins return an exit status of 2 to
     indicate incorrect usage.

However, sysexits.h has EX_USAGE == 64.  This is now exposed in Python 
2.3's os.EX_USAGE.

 > That said, if you feel a burning compulsion to make the change, go
 > ahead.

Not burning, just a mild compulsion to adhere to standards when 
relevant.  In this case there appears to be an old informal standard 
(exit status 2), and a new formal standard (EX_USAGE == 64) which 
doesn't appear to be well-known or -used.  So it's a toss-up.

 > no matter how hard I try, I can't make myself like "print >>".  ;-(

But you use it in OptionParser.print_usage and .print_version. ;-)
(For convenience, it appears.)

There's a slight difference in semantics with the change.  If the 
SystemExit exception is caught, no error message would be written wit 
the original code:

         sys.exit("%s: error: %s" % (get_prog_name(), msg))

But the error message would be written with the new code:

         sys.stderr.write("%s: error: %s\n" % (get_prog_name(), msg))
         sys.exit(2)

Very minor difference, and probably not significant.

-- David Goodger



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