I just tried this script, and it worked to paste into kwrite. I use ICEWM, so I was running kwrite without KDE....if that makes a difference like rovf mentioned. 
#!/usr/bin/perl
use warnings;
use strict;
use Tk;
use Tk::Clipboard;

my $mw = tkinit;
$mw->withdraw;  #use Tk without showing a window

my $content = 'foobar'.time;

print "$content\n";

$mw->clipboardClear;
$mw->clipboardAppend($content);

MainLoop;

[download]
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In reply to Re: Using X selection: copy and paste by zentara
in thread Using X selection: copy and paste by zink

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