This tutorial does not even come close to covering all the aspects of Perl. What it does is give the basics and then jump into some complex, but every day tasks that Perl can do. These tasks are jobs that you would normally use in building a website.
Perl is a free-form language like C. Perl's control flow is very much like C's and has no FORTRAN-like line contraints. Perl is an interpreted language, not compiled.
Perl programs usually end with .pl, but this is not a requirment as many Perl scripts used as CGI programs will end with .cgi. The first line of a Perl script ususlly starts with this:
#!/usr/bin/perl
which is the location of the Perl interpreter.
Perl ends every line with the semicolon(;). Lines that begin with the pound sign (#) are treated as comments and are ignored by the interpreter.
Blocks of Perl code are enclosed in curly brackets ( {...} ).