c:\@Work\Perl\monks\samira_saber>dir Volume in drive C is Acer Volume Serial Number is 9480-355B Directory of c:\@Work\Perl\monks\samira_saber 08/14/2017 05:23 PM . 08/14/2017 05:23 PM .. 08/14/2017 05:04 PM 759 process_file_1.pl 08/14/2017 04:40 PM 46 topol1.au 08/14/2017 04:40 PM 46 topol1.top 3 File(s) 851 bytes 2 Dir(s) 24,485,937,152 bytes free c:\@Work\Perl\monks\samira_saber>fc topol1.au topol1.top Comparing files topol1.au and TOPOL1.TOP FC: no differences encountered c:\@Work\Perl\monks\samira_saber>type topol1.top not so SOLITARY SOLUTION SOLVE the problem c:\@Work\Perl\monks\samira_saber>perl process_file_1.pl topol1.top processing 'topol1.top' c:\@Work\Perl\monks\samira_saber>dir Volume in drive C is Acer Volume Serial Number is 9480-355B Directory of c:\@Work\Perl\monks\samira_saber 08/14/2017 05:26 PM . 08/14/2017 05:26 PM .. 08/14/2017 05:04 PM 759 process_file_1.pl 08/14/2017 04:40 PM 46 topol1.au 08/14/2017 05:26 PM 61 topol1.top 08/14/2017 04:40 PM 46 topol1.top.bak 4 File(s) 912 bytes 2 Dir(s) 24,485,937,152 bytes free c:\@Work\Perl\monks\samira_saber>type topol1.top not so SOL my new stuff SOL my new stuff SOL my new stuff c:\@Work\Perl\monks\samira_saber>fc topol1.au topol1.top.bak Comparing files topol1.au and TOPOL1.TOP.BAK FC: no differences encountered