jeanluca has asked for the wisdom of the Perl Monks concerning the following question:

Dear Monks

I would like to capture everyting thats printed into a variable ( so I can wrap this into XML later on).
This is my test script so far 
#!/usr/bin/perl -l

use strict;
use warnings;

my $x ;
{
  local *STDOUT ;
  open STDOUT, ">$x" or die "nope\n";
  print "this is stored in \$x" ;
}
print $x ;

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Which doesn't work of course, perl now thinks $x contains a filename.
Any suggestions how to do this ?

Thnx
LuCa

UPDATE: Thanks a lot for the solutions/suggestions!!

Replies are listed 'Best First'.
Re: Redirect STDOUT to a $variable
by Corion (Patriarch) on Aug 10, 2007 at 11:31 UTC

    See open, where your case is discussed:

    close STDOUT;
open STDOUT, '>', \$variable or die "Can't open STDOUT: $!";

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[d/l]

      Rather than specifically closing STDOUT I opened a new file handle and selected it

      use strict;
print "1: to STDOUT.\n";
my $output = '';
open TOOUTPUT, '>', \$output or die "Can't open TOOUTPUT: $!";
print "2: to STDOUT.\n";
print TOOUTPUT "3: to TOOUTPUT.\n";
select TOOUTPUT;
print "4: To STDOUT, (really TOOUTPUT though).\n";
select STDOUT;
print "5: To STDOUT again\n";
print TOOUTPUT "6: To TOOUTPUT.\n";
print "----\n".$output."-----\n";
print "Now we're done.\n";

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      This is the results 
      1: to STDOUT.
2: to STDOUT.
5: To STDOUT again
----
3: to TOOUTPUT.
4: To STDOUT, (really TOOUTPUT though).
6: To TOOUTPUT.
-----
Now we're done.

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[d/l]
[select]
        Thank you very much, you helped a lot!
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      open (STDERR,'>&$var'); print $var; hope this wiil help u regards, san FREE as in FREEDOM thats life
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        >& does something completely different.
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Re: Redirect STDOUT to a $variable
by Moron (Curate) on Aug 10, 2007 at 11:53 UTC
    It's not abundantly clear what is wanted although taking your first statement in isolation, I would deduce (tentatively!) that (on *NIX) you'd want something like: 
    prog.pl | tee trapit.txt

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    and then postprocess what landed in the siphoned-off text file.

    On Windows there is no tee, so you'd have to overload the print function with your own routine to print both to STDOUT and somewhere else.

    Update: BUT if you can live with the output being completely redirected rather than just copied then... 

    prog.pl > trapit.txt

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    works on Windows and *NIX
    __________________________________________________________________________________

    ^M Free your mind!

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[d/l]
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Re: Redirect STDOUT to a $variable
by citromatik (Curate) on Aug 10, 2007 at 11:44 UTC

    Maybe it is enough to use sprintf:

    use strict;
use warnings;

my $x;
$x = sprintf ("%s","this is stored in \$x");
$x .= sprintf ("%s","... and this too\n");

print $x;

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    citromatik

    Update:Corrected sprintf syntax

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[d/l]
Re: Redirect STDOUT to a $variable
by bruceb3 (Pilgrim) on Aug 10, 2007 at 21:16 UTC
    Maybe the IO::String module from CPAN would give you the functionality that you are seeking?
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Re: Redirect STDOUT to a $variable
by Anonymous Monk on Nov 13, 2007 at 17:33 UTC
    I found that this works: sub print_to_var { my ($m, $v) = @_; local *STDOUT; open(STDOUT, ">", \$v); print $m; return $v; } #returns variable which contains string of $m printed
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