vi(1) doesn't disable xon/xoff mode when it sees a Control-V, nor does it
let you type Control-S or Control-Q into a file. The reason is that
Control-S and Control-Q are special characters for controlling output flow.
If you precede your "vi" with "stty -ixon", flow control will be disabled,
allowing generation of these characters within your file.
"stty ixon" is the default on login.
Article Change History:
06 Jun 1993 - Revised for clarity.
31 Aug 1992 - Reviewed for technical accuracy.