Re: [PLUG] question re: perl diamond operator

[Edmond Rodriguez <erodrig_97@yahoo.com>]

Possibly meant this ( .... loop through....)

#!/usr/bin/perl

$missingFileFlag=0;
foreach my $file (@ARGV) {
if (! -f $file) {
   print "$file does not exist\n";
   $missingFileFlag=1;
   }
}
exit 1 if ( $missingFileFlag );

while (<>) {
     chomp;
     print $_;
 }





----- Original Message ----
> From: Mark M. Hoffman <mhoffman@lightlink.com>
> To: Philadelphia Linux User's Group Discussion List <plug@lists.phillylinux.org>
> Sent: Thursday, June 25, 2009 3:07:34 PM
> Subject: Re: [PLUG] question re: perl diamond operator
> 
> Hi:
> 
> * Paul W. Roach III [2009-06-25 14:23:22 -0400]:
> >    Yeah...
> >    *
> >    #!/usr/bin/perl
> >    *
> >    foreach my $file (@ARGV) {
> >    ** open(FILE, $file) || die "couldnt open file $file: $!\n";
> >    ** chomp(my @lines = );
> >    ** close(FILE);
> >    *
> >    ** print @lines;
> >    }
> 
> Yes obviously... but then I lose the ability to (also) do this:
> 
>     $ some_command | ./example.pl
> 
> I asked about the diamond operator, specifically, for good reason.
> 
> >    On Thu, Jun 25, 2009 at 1:14 PM, Morgan Jones <[1]morgan@morganjones.org>
> >    wrote:
> > 
> >      You could also loop through %ARGV and test each value.
> > 
> >      [2]http://en.wikipedia.org/wiki/There%27s_more_than_one_way_to_do_it
> >      -morgan
> > 
> >      On Jun 25, 2009, at 1:03 PM, Mark M. Hoffman wrote:
> > 
> >      > Hi:
> >      >
> >      > * Morgan Jones <[3]morgan@morganjones.org> [2009-06-25 12:47:38
> >      -0400]:
> >      >> #! /usr/bin/perl -w
> >      >>
> >      >> if (! -f $ARGV[0]) {
> >      >> * * print "$ARGV[0] does not exist\n";
> >      >> * * exit 1;
> >      >> }
> >      >>
> >      >> while (<>) {
> >      >> * * *chomp;
> >      >> * * *print $_;
> >      >> }
> >      >
> >      > Sure I could do that, but consider...
> >      >
> >      > * * * $ ./example.pl this_file_exists but_not_this_one
> >      >
> >      > It's a bit indirect, but I've solved it a completely different way.
> >      > I added
> >      > the following line near the top... it installs a warning handler
> >      > which just
> >      > converts all warnings into fatal errors. *Good enough for me.
> >      >
> >      > * * * local $SIG{__WARN__} = sub { die $_[0] };
> >      >
> >      >> On Jun 25, 2009, at 12:24 PM, Mark M. Hoffman wrote:
> >      >>
> >      >>> Hi all:
> >      >>>
> >      >>> Given the following trivial script:
> >      >>>
> >      >>>>> #! /usr/bin/perl -w
> >      >>>>>
> >      >>>>> while (<>) {
> >      >>>>> * chomp;
> >      >>>>> * print $_;
> >      >>>>> }
> >      >>>
> >      >>> * * $ ./example.pl foo
> >      >>> * * Can't open foo: No such file or directory at ./example.pl line
> >      3.
> >      >>>
> >      >>> So far so good; the file foo really does not exist.
> >      >>>
> >      >>> * * $ echo $?
> >      >>> * * 0
> >      >>>
> >      >>> Really? *I want the exit status to be non-zero here. *I've looked
> >      >>> through the
> >      >>> perl documentation; I can't see any way to get the diamond operator
> >      >>> to do what
> >      >>> I want in this case. *I would appreciate any suggestions from perl
> >      >>> experts.
> >      >
> 
> Regards,
> 
> -- 
> Mark M. Hoffman
> mhoffman@lightlink.com
> 
> ___________________________________________________________________________
> Philadelphia Linux Users Group         --        http://www.phillylinux.org
> Announcements - http://lists.phillylinux.org/mailman/listinfo/plug-announce
> General Discussion  --   http://lists.phillylinux.org/mailman/listinfo/plug

___________________________________________________________________________
Philadelphia Linux Users Group         --        http://www.phillylinux.org
Announcements - http://lists.phillylinux.org/mailman/listinfo/plug-announce
General Discussion  --   http://lists.phillylinux.org/mailman/listinfo/plug