If you haven't already, read perldoc perlipc for information of setting up signal handlers using %SIG. The HUP, USR1, and USR2 signals are good candiates. The usual idiom is to have the handler set a flag, and then you check that flag in your main loop. 

my $reload_config = 0;
$SIG{USR1} = sub { $reload_config = 1 };
...
while( $yadda_yadda_yadda ) {
  check_something( $something );
  poll_for_widgets( $mywidgets );

  if( $reload_config ) {
    reload_my_config( $config );
    $reload_config = 0;
  }
}

[download]

As for sending interrupts from the keyboard, you're pretty much limited to INT, QUIT, and TSTP as far as what you can send from the keyboard with a plain tty driver. Usually stty -a will give a list of what keys will send what particular signal. For example here's what I get on Linux (YDL 2.0 PPC): 

speed 38400 baud; rows 30; columns 80; line = 0;
intr = ^C; quit = ^\; erase = ^?; kill = ^U; eof = ^D; eol = <undef>;
eol2 = <undef>; start = ^Q; stop = ^S; susp = ^Z; rprnt = ^R; werase =
+ ^W;
...

[download]

Ctrl-c will send SIGINT, Ctrl-\ will send SIGQUIT, and Ctrl-z sends SIGTSTP. You can't really send other signals (USR1, HUP, et al) easily from the keyboard, but you can always have your program write out its PID to a file and then use backticks in your shell to do kill -HUP `cat /var/run/myprog.pid`.

You may also want to look into Event or POE, both of which provide ways of triggering events in your program when signals are received.

In reply to Re: Using traps to autoincrement / decrement variables by Fletch
in thread Using traps to autoincrement / decrement variables by Anonymous Monk

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