use Getopt::Std;

$usemsg = "Usage:  pre_DAD.pl -i <input_folder> -w <working_dir> -o <output_file> \n";

getopts('i:o:w:', \%options);

if ((!exists $options{i}) || (!exists $options{o}) || (!exists $options{w}) )  {
        die $usemsg;
}

$inputfolder    = $options{i};
$outputfile     = $options{o};
$workingdir     = $options{w};




#open the input directory to get a file list
opendir(my $indir, $inputfolder) || die "Can't open input directory $inputfolder $! \n";


while (readdir $indir) {
  if ($_ =~ /txt$/){
my $tfn = "/".$_;
move ($inputfolder.$tfn,$workingdir);
}
}
# close the input directory
closedir $indir;