Modules. Installation. Unix Daemons in Perl. Unix Daemons in Perl Writing the Daemon Now that we understand the basic attributes of a daemon, let's put the pieces together into a simple Perl program: Simple Daemon: Listing 1 use POSIX qw(setsid); chdir '/' or die "Can't chdir to /: $! "; umask 0; open STDIN, '/dev/null' or die "Can't read /dev/null: $! " The example above is a simple daemon that will print Hello... to the console every five seconds.
Web Mirror: Listing 2 For example, let's say we need a daemon that mirrors a Web page on a pre-production server. Xah: Perl-Python Tutorial. Writing serious Perl: The absolute minimum you need to know. Abstract Perl's extremely flexible syntax makes it easy to write code that is harder to read and maintain than it could be. This article describes some very basic practices I consider necessary for a clear and concise style of writing Perl. Table of contents Namespaces One package should never mess with the namespace of another package unless it has been explicitly told to do so.
Package Sophie; sub say_hello { print "Hi World! " Rooting a namespace When you use an unloaded package Some::Package , Perl looks for a file Some/Package.pm in the current directory. It is a good idea to save your application packages to a directory like lib and add that directory to the list of namespace roots using use lib 'my/root/path' : use lib 'lib'; # Add the sub-directory 'lib' to the namespace root @INC use Some::Package; # Walks through @INC to find the package file Exporting symbols There are rare occasions when you do want to export methods or variable names into the calling package.
Instant data structures. Perl tutorial: Start. Perl Tutorial. Tutorials | Introduction to Perl 5 for Web Developers | Table of Contents.