There's an example of this in L<perlfunc/crypt>). First, you put the
terminal into "no echo" mode, then just read the password normally.
You may do this with an old-style ioctl() function, POSIX terminal
-control (see L<POSIX> and Chapter 7 of the Camel, 2nd ed.), or a call
+control (see L<POSIX> or its documentation the Camel Book), or a call
to the B<stty> program, with varying degrees of portability.
You can also do this for most systems using the Term::ReadKey module
# been opened on a pipe...
system("/bin/stty $stty");
$_ = <MODEM_IN>;
- chop;
+ chomp;
if ( !m/^Connected/ ) {
print STDERR "$0: cu printed `$_' instead of `Connected'\n";
}
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 L<perlipc/"Signals"> and chapter 6 of the Camel.
+Signals are documented in L<perlipc/"Signals"> and the
+section on ``Signals'' in the Camel.
Be warned that very few C libraries are re-entrant. Therefore, if you
attempt to print() in a handler that got invoked during another stdio
you're in a "slow" call, such as <FH>, read(), connect(), or
wait(), that the only way to terminate them is by "longjumping" out;
that is, by raising an exception. See the time-out handler for a
-blocking flock() in L<perlipc/"Signals"> or chapter 6 of the Camel, 2nd ed.
+blocking flock() in L<perlipc/"Signals"> or the section on ``Signals''
+in the Camel book.
=head2 How do I modify the shadow password file on a Unix system?
Perl's exception-handling mechanism is its eval() operator. You can
use eval() as setjmp and die() as longjmp. For details of this, see
the section on signals, especially the time-out handler for a blocking
-flock() in L<perlipc/"Signals"> and chapter 6 of the Camel 2nd ed.
+flock() in L<perlipc/"Signals"> or the section on ``Signals'' in
+the Camel Book.
If exception handling is all you're interested in, try the
exceptions.pl library (part of the standard perl distribution).
The IPC::Open2 module (part of the standard perl distribution) is an
easy-to-use approach that internally uses pipe(), fork(), and exec() to do
the job. Make sure you read the deadlock warnings in its documentation,
-though (see L<IPC::Open2>). See L<perlipc/"Bidirectional Communication
-with Another Process"> and L<perlipc/"Bidirectional Communication with
-Yourself">
+though (see L<IPC::Open2>). See
+L<perlipc/"Bidirectional Communication with Another Process"> and
+L<perlipc/"Bidirectional Communication with Yourself">
You may also use the IPC::Open3 module (part of the standard perl
distribution), but be warned that it has a different order of
=head2 How do I timeout a slow event?
Use the alarm() function, probably in conjunction with a signal
-handler, as documented in L<perlipc/"Signals"> and chapter 6 of the
-Camel. You may instead use the more flexible Sys::AlarmCall module
-available from CPAN.
+handler, as documented in L<perlipc/"Signals"> and the section on
+``Signals'' in the Camel. You may instead use the more flexible
+Sys::AlarmCall module available from CPAN.
=head2 How do I set CPU limits?