$a = 'a.txt';
open(IN,$a) || die "cannot open $a for reading: $!";
$b = 'time.txt';
open(OUT,">>$b") || die "cannot create $b: $!";
while (<IN>) {
	# read a line from file $a into $_ 
	#print OUT $_;
	if (/returns \d{1} \(in \d{1}.\d{6} secs/) {
		print OUT ?? ;
	}
	
} 
close(IN)    || die "can't close  $a:$!"; 
close(OUT) || die "can't close  $b:$!";