use Tk;
use Tk::Text ;
.
.
.
my $txt = $mw->Text( -background =>'white', )-> pack ();
.
.
.
$txt -> delete('1.0','end');
[download]

Please, do not link to sites that break copyright.

Ok, I removed the copyright link. Actually I don't know this.

#!/usr/local/bin/perl
#an index is passed to the insert method to insert text into the text 
+widget.
#the index is passed along with the text to be inserted.
#There are two general ways to specify an index for Tk:
#01- use the end token.
#02- specify the row.position combination.

#the row is 1-based and the position is 0-based.

use strict;
use warnings;
use Tk;

my ($main, $text);

$main=MainWindow->new();
$main->Button(
                -text=>'Type',
                -relief=>'raised',
                -command=>\&display)->pack;
$main->Button(
                -text=>'delete',
                -relief=>'ridge',
                -command=>\&deleting)->pack;
$main->Button(
        -text=>'exit',
        -relief=>'groove',
        -command=>[$main=>'destroy']
        )->pack;
        
$main->Button(
        -text=>'Position',
        -relief=>'raised',
        -command=>\&position
        )->pack;
        
$text=$main->Text(-width=>40, -height=>8)->pack;

sub display{
        $text->insert('2.0', "Greetings\n"); #insert at the secondRow.
+FirstPosition, #This only works after deleting text from the text wid
+get
        }
        
sub deleting{
        $text->delete('1.0','2.9');
        }
        
sub position{
        $text->get('2.0','1.9');
        }
MainLoop;
[download]

You can pass an empty string to 'Contents' method.

Query or change the entire contents of the text widget. If no arguments are given, the entire contents of the text widget are returned. If any arguments are given, the entire contents of the text widget are deleted and replaced by the argument list