#! is often pronounced she-bang, which is short for sharp (the musicians name for the # character), and bang, which is another name for the exclamation point. This notation is also used in shell scripts. See Chapter 15, "Automating Tasks," for more information about writing shell scripts.

The #! line is technically not part of the Perl code at all. The # character indicates that the rest of the screen line is a comment. The comment is a message to the shell, telling it where it should go to find the executable to run this program. The interpreter ignores the comment line.

Exceptions to this practice include when the # character is in a quoted string and when it is being used as the delimiter in a regular expression. Comments are useful to document your scripts, like this:

# a simple example to print a greeting print "hello there\n";

A block of code, such as what might appear inside a loop or a branch of a conditional statement, is indicated with curly braces ({}). For example, here is an infinite loop:

# a block of code to print a greeting forever while (1) {

print "hello there\n";

Perl statements are terminated with a semicolon. A Perl statement can extend over several actual screen lines because Perl is not concerned about whitespace.

The second line of the simple program prints the text enclosed in quotation marks. \n is the escape sequence for a newline character.

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