Summary: How to fix the behavior on linux with putty that pressing 'CTRL' + 'S' seems to freeze the box.
Date: Around 2015
Refactor: 9 January 2025: Checked links and formatting.

Whenever I press CTRL+S in putty the terminal seems to freeze. It's actually not, but it doesn't show anything. That is because CTRL+S initiates the XOFF command, which means it accepts keystrokes but doesn't show it. There are two fixes:

Press CTRL+Q to initiate the XON command. Anything you pressed will be shown.

Add this line to your .bashrc file:

stty ixany

Now, when you hit CTRL+S the XOFF gets initiated but any character will start XON.