use DB_File ;
my  %hash;

     unlink "tempfile"; #Remove previous file, if any
tie %hash, "DB_File", "tempfile", O_RDWR|O_CREAT, 0666, $DB_HASH 
     or die "Cannot open file 'tempfile': $!\n";

while($sourceString =~ /example(key)regex(value)example\b/ig ) {
     my $key = $1;
     my $value = $2;
     push( @{ $hash{ $key } },  $value );  #Push the value into the hash
}