I have tried to find out in full detail about the file handle $ARGV and only got the basics. Could any one please explain the $ARGV in more detail, e.g. how to put a input file into the $ARGV, if the input file was constantly changing! The File in may program: ################ open iscd,"<$ARGV[0]" or die "Cannot open $ARGV[0]",$!; open sortcode,">$ARGV[1]"; while($line=<iscd>){ ################ Thanks, GD