Just in case you have a legitimate need to put a file onto a label, here are a few tips. You need to watch your -wraplength, -anchor, and -justify.

I suppose for small files, that you want to display readonly, and don't want the overhead of the full Text widget, a Label might be a good choice for display.

#!/usr/bin/perl
use strict;
use Tk;

my $mw = Tk::MainWindow->new();

#open this script as an example
open(  my $fh,"< $0" ) or die "$!\n"; 
my $buf;
read( $fh, $buf, -s $fh );
close $fh;


my $lab1=$mw->Label(-text => 'abc abc abc abc abc abc abc abc abc abc 
+abc abc',
    -bg=>'white',
    -width => 40,
    -wraplength => 200,
    )->pack(-expand=> 0, -fill=> 'x');

my $lab2=$mw->Label(-text => 'abc abc abc abc abc abc abc abc abc abc 
+abc abc',
    -bg=>'lightblue',
    -width => 40,
    -wraplength => 100,
    )->pack(-expand=> 0, -fill=> 'x');


my $lab3=$mw->Label(-text => $buf,
    -bg=>'hotpink',
    -width => 40,
    -wraplength => 200,
    -justify => 'left',
    -anchor  => 'w',
    )->pack(-expand=> 0, -fill=> 'x');

MainLoop;
[download]