my @a_csv_tmp = grep  !/$h_csv_ref/ , @a_h_csv_ref;
while( @a_h_csv_ref ) { shift( @a_h_csv_ref ); }
push(  @a_h_csv_ref, @a_csv_tmp );
while( @a_csv_tmp   ) { shift( @a_csv_tmp   ); }

open( ERR, ">>$bindir/mailtext.txt" );
   print ERR ">>>> h_csv_ref ############\n";
   print ERR $h_csv_ref . "\n";
   print ERR "<<< #######################\n\n";
   print ERR ">>>> a_csv_tmp ############\n";
   foreach my $eintrag_1 ( @a_csv_tmp )   { print ERR $eintrag_1 . "\n"; }
   print ERR "<<< #######################\n\n";
   print ERR ">>>> a_h_csv_ref ##########\n";
   foreach my $eintrag_2 ( @a_h_csv_ref ) { print ERR $eintrag_2 . "\n"; }
   print ERR "<<< #######################\n\n";
close( ERR );