Perl

Perl is an interpreted language, existing mostly on Linux and UNIX-based platforms. It actually runs on almost all platforms, but you find it most often on Linux and UNIX-based ones. Anyway, here is the Perl version of the program, which should be typed into a file named Hello-World.pl:

 #!/usr/bin/perl print("Hello world!\n"); 

Since Perl is interpreted, you don't need to compile or link it. Just run in with the following command:

 perl Hello-World.pl 

As you can see, the Perl version is even shorter than the C version. With Perl you don't have to declare any functions or program entry points. You can just start typing commands and the interpreter will run them as it comes to them. In fact this program only has two lines of code, one of which is optional.

The first, optional line is used for UNIX machines to tell which interpreter to use to run the program. The #! tells the computer that this is an interpreted program, and the /usr/bin/perl tells the computer to use the program /usr/bin/perl to interpret the program. However, since we ran the program by typing in perl Hello-World.pl, we had already specified that we were using the perl interpreter.

The next line calls a Perl builtin function, print. This has one parameter, the string to print. The program doesn't have an explicit return statement - it knows to return simply because it runs off the end of the file. It also knows to return 0 because there were no errors while it ran. You can see that interpreted languages are often focused on letting you get working code as quickly as possible, without having to do a lot of extra legwork.

One thing about Perl that isn't so evident from this example is that Perl treats strings as a single value. In assembly language, we had to program according to the computer's memory architecture, which meant that strings had to be treated as a sequence of multiple values, with a pointer to the first letter. Perl pretends that strings can be stored directly as values, and thus hides the complication of manipulating them for you. In fact, one of Perl's main strengths is its ability and speed at manipulating text.