hi, Try out this one.

#!/usr/bin/perl
open FH,"inputfile";
while(<FH>){
     $head=();$str=();
     if($_=~m/^>/){
        ($head,$x)=split(' ',$_);
        $head=~s/length=\d+\n+\s+//g;
        print $head;
     }
     else{
        $str=$_;
        chomp($str);
        $len=length($str);
        print "  Length=$len\n";
        print "$str\n";
        $len=();
     }
}
[download]