#!/usr/bin/perl -w

use strict;

system("pvscan>>pv.txt1");
open my $FH,"pv.txt1"  or die "Cannot open file: $!";

while(my $line = <$FH>){
        my $pvname = $line =~ /\[\d+\.\d+\sGB\s\/\s\d+\.\d+\sGB\]/i;
        print $pvname;

}