... and run the script as C</path/to/script.pl>. Of course, it'll need
to be executable first, so C<chmod 755 script.pl> (under Unix).
+(This start line assumes you have the B<env> program. You can also put
+directly the path to your perl executable, like in C<#!/usr/bin/perl>).
+
For more information, including instructions for other platforms such as
Windows and Mac OS, read L<perlrun>.
=head2 Safety net
-Perl by default is very forgiving. In order to make it more roboust
-it is recommened to start every program with the following lines:
+Perl by default is very forgiving. In order to make it more robust
+it is recommended to start every program with the following lines:
#!/usr/bin/perl
use strict;
use warnings;
-The C<use strict;> line imposes some restrictions that will mainly stop
-you from introducing bugs in your code. The C<use warnings;> is more or
-less equivalent to the command line switch B<-w> (see L<perlrun>). This will
-catch various problems in your code and give warnings.
+The two additional lines request from perl to catch various common
+problems in your code. They check different things so you need both. A
+potential problem caught by C<use strict;> will cause your code to stop
+immediately when it is encountered, while C<use warnings;> will merely
+give a warning (like the command-line switch B<-w>) and let your code run.
+To read more about them check their respective manual pages at L<strict>
+and L<warnings>.
=head2 Basic syntax overview
Using C<my> in combination with a C<use strict;> at the top of
your Perl scripts means that the interpreter will pick up certain common
programming errors. For instance, in the example above, the final
-C<print $b> would cause a compile-time error and prevent you from
+C<print $y> would cause a compile-time error and prevent you from
running the program. Using C<strict> is highly recommended.
=head2 Conditional and looping constructs
Exactly like C:
- for ($i=0; $i <= $max; $i++) {
+ for ($i = 0; $i <= $max; $i++) {
...
}
the meantime, here's a quick cheat sheet:
. a single character
- \s a whitespace character (space, tab, newline)
+ \s a whitespace character (space, tab, newline, ...)
\S non-whitespace character
\d a digit (0-9)
\D a non-digit
also available from CPAN.
To learn how to install modules you download from CPAN, read
-L<perlmodinstall>
+L<perlmodinstall>.
To learn how to use a particular module, use C<perldoc I<Module::Name>>.
Typically you will want to C<use I<Module::Name>>, which will then give