open my $OUT, '>>', "$mycrdir/file_detail.txt" or die "Can't create '$mycrdir/file_detail.txt'" ;

##</code><code>##

my $filename = "$mycrdir/file_detail.txt";
open my $OUT, '>>', $filename
  or die "Can't create '$filename'";

##</code><code>##

open my $OUT, '>>', $filename
  or die "Can't create '$filename': $!";