Using a double quoted . the answer is first , second 
Using an escaped  . the answer is first , second 
Using a double quoted, double escaped . the answer is first data1, second txt
Using a single quoted . the answer is first , second 
Using a single quote escaped . the answer is first data1, second txt
Using a single quote double escaped . the answer is first data1, second txt
Using  /./ in split the answer is first , second 
Using  /\./ in split the answer is first data1, second txt
Using  /\\./ in split the answer is first data1.txt, second