functional language called ML, which was developed in the early 1970s.
OCaml is used primarily, but not exclusively, in the financial world, in
programs for electronic trading, markets, and investments. It has an advanced
type system and supports not only functional but also imperative and object-
oriented styles of programming. It includes a memory manager and
incremental garbage collection.
To use OCaml on Ubuntu, you write programs in your favorite text editor. To
run them, you need the package ocaml, which includes two compilers:
ocamlc compiles to bytecode, and ocamlopt compiles to native code.
Perl
Perl is a well-established programming language that has been around since
the 1980s. It started as a Common Gateway Interface (CGI) language for web
servers. Over time, people have used it for scripting, systems administration,
network programming, and a ton of other things. You will find Perl
everywhere being used in ways never dreamed of by its originators. It is an
incredibly flexible and powerful language. The downside to this is that it is
also a complex language that some jokingly describe as looking like a cat
walked across your keyboard. If you know what you are doing with Perl, you
can work magic. If you can’t remember what you did and didn’t document it,
you will probably end up hating yourself along with anyone else who has to
interact with your code. All joking aside, it is worth learning, even just a little.
Perl is installed by default and already in use on your system. To use Perl on
Ubuntu, you write programs in your favorite text editor. Nothing special is
needed. Put the script somewhere and run it from the command line, like this:
perl yourscriptname.pl.
This book has a digital-only chapter on the Perl language, available at
http://www.informit.com/title/9780134985466.
PHP
PHP is another well-established programming language originally created for
web development but that now sees use in many other roles. Often it is used
for simple scripts on servers. PHP is kind of a cross between Java and Perl. It
is quick and easy to learn and commonly found. PHP is another language
worth learning, even if just a little.
PHP is installed by default and already in use on your system. To use PHP on
Ubuntu, you write programs in your favorite text editor. Nothing special is