How do I trap control characters/signals?
       You don't actually "trap" a control character.  Instead, that character generates a signal which is sent to your terminal's currently foregrounded process group,
       which you then trap in your process.  Signals are documented in "Signals" in perlipc and the section on "Signals" in the Camel.

       You can set the values of the %SIG hash to be the functions you want to handle the signal.  After perl catches the signal, it looks in %SIG for a key with the
       same name as the signal, then calls the subroutine value for that key.

               # as an anonymous subroutine

               $SIG{INT} = sub { syswrite(STDERR, "ouch\n", 5 ) };

               # or a reference to a function

               $SIG{INT} = \&ouch;

               # or the name of the function as a string

               $SIG{INT} = "ouch";

       Perl versions before 5.8 had in its C source code signal handlers which would catch the signal and possibly run a Perl function that you had set in %SIG.  This
       violated the rules of signal handling at that level causing perl to dump core. Since version 5.8.0, perl looks at %SIG *after* the signal has been caught, rather
       than while it is being caught.  Previous versions of this answer were incorrect.