We describe some of the most important features of the most important modules in this section. The modules that we discuss here should be found on every machine that has Perl except where noted otherwise. You can get the latest ones from CPAN.
Many people use Perl to write programs that a web server will run, called CGI program s. The
CGI module comes with Perl, and the
CGI_Lite module is available separately from CPAN. We showed an example in Chapter 15, and you can read more in the section "The Common Gateway Interface (CGI)" later in this appendix.
Sometimes you need to know what the current working directory’s name is. (You could use
., but maybe you need to save the name so you can change back to this directory later.) The
Cwd module, which comes with Perl, provides the
cwd function, which you can use to determine the current working directory.
use Cwd; my $directory = cwd;
If you get tired of writing "
or die" after every invocation of
chdir, then maybe the
Fatal module is for you. Tell it which functions to work with, and those will be automatically checked for failure as if you’d written
or die and a suitable message after each one. This won’t affect such calls in someone else’s package (code contained within a module you’re using, for example), so don’t use this to fix poorly written code. It’s a timesaver for simple programs in which you don’t need direct control over the error ...