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From: lwall@jpl-devvax.JPL.NASA.GOV (Larry Wall)
Newsgroups: comp.lang.perl
Subject: Re: PERL mucks with "magic number?"
Message-ID: <8045@jpl-devvax.JPL.NASA.GOV>
Date: 9 May 90 23:20:38 GMT
References: <1990May8.220641.20501@uvaarpa.Virginia.EDU> <15471@bfmny0.UU.NET> <saG7MtO00WB40Nw3NM@andrew.cmu.edu>
Reply-To: lwall@jpl-devvax.JPL.NASA.GOV (Larry Wall)
Organization: Jet Propulsion Laboratory, Pasadena, CA
Lines: 17

In article <saG7MtO00WB40Nw3NM@andrew.cmu.edu> rm55+@andrew.cmu.edu (Rudolph T. Maceyko) writes:
: Here's one for you.  Say I have a PERL script which begins with
: #!/short/path/to/perl ;-> ...  Does PERL get invoked TWICE in order to
: execute the script?  Once from the kernel, and once again by PERL?
: And, if so, how does PERL know when to stop, since it'll see the #!
: again?

Well, it seems obvious from its current behavior that it has to stop some
time, so it might as well stop before the first extra exec...

I quote the following three lines from toke.c for your amusement:

    if (line == 1) {
	if (*s == '#' && s[1] == '!') {
	    if (!in_eval && !instr(s,"perl") && instr(origargv[0],"perl")) {

Larry