use strict;
use warnings;
my $string = '0123efg789efg13';
my @matches;
my $x='efg'; #the pattern
for (0..10000) {

    if($string =~ /$x/g){
    push @matches, $-[0];
    push @matches, $+[0]-1;
    push @matches,"\n";
    }
    
    else {last}
    
}
print "@matches\n";