exec "nohup ./error_summariser.cgi $identifier > $default_files_dir/$identifier/processing-log.txt &" or die "Can't exec: $!\n";

##</code><code>##

exec "nohup ./error_summariser.cgi $identifier > $default_files_dir/$identifier/processing-log.txt 2>/dev/null &" or die "Can't exec: $!\n";