perl -p -e "s/\r+//" file.txt > newfile.txt

##</code><code>##

while  (<FILE>){

  /ATDT\d+\s+BUSY/ ? print : print "Did not match '$_'\n";

  #print if /ATDT\d+\s+BUSY/;

  #print if /ATDT\d+.*BUSY/s; 

  #print;

}

##</code><code>##

The system cannot find the file specified.

##</code><code>##

Did not match 'Output: Got ."ATDT1234567'
'
Did not match 'BUSY