Each of the these will be discussed in turn.

Every perl program starts with this statement as its very first line:

This may also vary from system to system. This statement tells the machine what action to carry with the file when it is executed, It tells the machine to run the file through perl.

Comments can be inserted in a program using the "#" symbol, and all that comes after # to the end of the line is ignored (but this is not applicable for the first line of the program). The only way to apply comments over several lines is to use a # on each line.

Everything else then comment and first line is a Perl statement and must end with a semicolon, like last line in the above code.

The print function outputs information we want to print. In the above program it prints out the string Hello world. and here also the statement ends with a semicolon.

You will find that the above program produces a slightly unexpected result. So the next thing is to run it.