c:\test>perl -MO=Deparse -l -0x3e -ane"@F||next; s/length=//for$F[1]; @F[5]=join'',@F[5..99]; $#F=5; print'>',join',',@F" junk.dat
BEGIN { $/ = ">"; $\ = "\n"; }
LINE: while (defined($_ = <ARGV>)) {
    chomp $_;
    our(@F) = split(' ', $_, 0);
    next unless @F;
    s/length=// foreach ($F[1]);
    @F[5] = join('', @F[5..99]);
    $#F = 5;
    print '>', join(',', @F);
}
-e syntax OK