Unix command: stty

stty is a command which changes the behavior of terminal line setting. The usage can be found in its manual page.
There are some useful options:
- List out current terminal line setting: stty -a
- Prevent character printed out while input via keyboard (useful in enter passwd):stty -echo
- Permit character printed out while input via keyboard: stty echo
- Handle each input character per time instead of one line per time (useful in handle special character): stty cbreak
- Handle each input line per time (the default behavior): stty -cbreak

Perl comments

Perl is simple and powerful in automation; but quite ambiguous and lack of user-defined data structure.