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Re: [perl #2783] Security of ARGV using 2-argument open - historicity

In-Reply-To: Message from Mark Mielke <mark@mark.mielke.cc> 
   of "Sat, 26 Jul 2008 16:29:40 EDT." <488B8934.3050204@mark.mielke.cc> 
> Users who don't read the document will always be surprised.  In
> standard Unix, passing a "-" in has traditionally meant STDIN.
For input; for output, it's meant stdout, the standard output.
Compare
    % tar cf - | gzip > foo.tar.gz
    % gunzip < foo.tar.gz | tar xf - 
As for piping to/fro "-", that's a Perl innovation, but it still means
"to/fro the *standard* thing" (of which [per Descartes] the only such
standard upon whose existence we can be certain is the very querent
it/him/our/themself; hence, the fork, being ourselves of the only entity
   guaranteed to exist).
> One could argue that an experienced user might be "surprised" that "-"
> was NOT interpreted as STDIN.  This argument is entirely relative to
> the person's expectations.
> In this case, the expectations should be well instilled. Perl has done
> what it has done for over a decade, 
While what you said is not false, it doesn't convey the historicity.
You could have said over a month and been equally correct.
Perl has *always* done this.  Witness:
    % perl1 -e 'while(<>) {print "$ARGV $. $_";}' /etc/motd - /etc/motd < /etc/motd
    /etc/motd 1 This particularly rapid unintelligible patter 
    /etc/motd 2 isn't generally heard and if iTIS it doesn't matter.
    - 3 This particularly rapid unintelligible patter 
    - 4 isn't generally heard and if iTIS it doesn't matter.
    /etc/motd 5 This particularly rapid unintelligible patter 
    /etc/motd 6 isn't generally heard and if iTIS it doesn't matter.
    % perl1 -v
    $Header: perly.c,v 1.0 87/12/18 15:53:31 root Exp $
    Patch level: 0
> and if somebody is truly surprised today - they should pick up the
> manual and give it another read.
Even in our post-literate uncivilization? :-(
--tom

• Re: [perl #2783] Security of ARGV using 2-argument open - historicity by Tom Christiansen