difference \n \r

\n is the classic line_feed on Unix/Linux (his ascii is 10 in decimal and 0a in hexadecimal)
\r\n is the classic line_feed on Windows
\r is the classic line_feed on olds version of MacOs (pre-MacOsX version) (his ascii is 13 in decimal an 0d in hexadecimal)

Here is what the above code is Doing:
1. It’s creating a variable called ‘line_feed’ and assigning it the value of ‘\n’
2. It’s creating a variable called ‘line_feed_windows’ and assigning it the value of ‘\r\n’
3. It’s creating a variable called ‘line_feed_mac’ and assigning it the value of ‘\r’
4. It’s printing out the value of ‘line_feed’
5. It’s printing out the value of ‘line_feed_windows’
6. It’s printing out the value of ‘line_feed_mac’