Here is one way to do it:

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

@ARGV = ( '148Nsorted.bed', '162Nsorted.bed', '174Nsorted.bed', '175Ns
+orted.bed' );
my %data;
while ( <> ) {
    /^\s*(\S+)\s+(\d+)\s+(\d+)\s*$/ or next;
    $data{ $1 } |= '0' x ( $2 - 1 ) . '1' x ( $3 - ( $2 - 1 ) );
    }

keys( %data ) == 1 or die "Error: too many keys.\n";
my ( $name, $string ) = each %data;
$string =~ /10+1/ and die "Error: no overlap.\n";
$string =~ /^0*1/ and my $start = $+[ 0 ];
$string =~ /.*1/  and my $end   = $+[ 0 ];

print "$name\t$start\t$end\n";
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