Path: utzoo!utgpu!news-server.csri.toronto.edu!cs.utexas.edu!wuarchive!usc!elroy.jpl.nasa.gov!jpl-devvax!lwall
From: lwall@jpl-devvax.JPL.NASA.GOV (Larry Wall)
Newsgroups: comp.lang.perl
Subject: Re: perl 3@40 fails test lib.big
Message-ID: <10394@jpl-devvax.JPL.NASA.GOV>
Date: 15 Nov 90 18:33:59 GMT
References: <1990Nov10.230258.21946@ircam.ircam.fr> <1990Nov14.140021.5953@ping.uucp>
Reply-To: lwall@jpl-devvax.JPL.NASA.GOV (Larry Wall)
Organization: Jet Propulsion Laboratory, Pasadena, CA
Lines: 24

In article <1990Nov14.140021.5953@ping.uucp> gorpong@ping.uucp (Gordon C. Galligher) writes:
: I also believe that the first line of lib.big should be ./perl -x
: not just perl, in order to take advantage of the __END__ stuff in the file.
: I executed ./perl lib.big and ./perl -x lib.big and it works regardless of
: the -x switch.  Is it a side effect that if an __END__ exists then the rest
: is automatically used as <DATA> and the -x is not needed, or is the -x merely
: there to tell perl to skip to a #!perl and start executing to an __END__?

The -x has nothing to do with __END__, other than the similarity that
both are used to trim excess garbage from a script.  The -x lets you trim
garbage before #!.  The __END__ lets you trim garbage after the __END__.

The -x is really only useful when the #! line is not the first line of the
file.  Ordinary scripts never need it--the intent is to allow you to pipe
articles to perl that contain scripts.

<DATA> will work any time there is an __END__.

Your make problem sounds like it stems from a make that supplies a different
context than the shell.  Perhaps there is some subtle interaction between
DATA and STD{IN,OUT,ERR}.  Some makes attach STDIN to /dev/null, for
instance.  I don't know why that would louse up DATA though.

Larry