If you have written programs longer than one hundred lines or so, I don’t need to tell you how important it is to organize programs into subroutines. But for some reason, many Perl programmers seem to be allergic to them.I tend to use a lot of subroutines. In fact, when I start a new project, I usually write a subroutine with the same name as the program, and start the program by invoking it. sub [...]

What could possibly go wrong? Only three things: Compile-time error:  Perl compiles the entire program before it starts exe-cution. If there is a syntax error anywhere in the program, the compiler prints an error message and stops without attempting to run the program. Run-time error: If the program compiles successfully, it will start executing,but if anything goes wrong during execution, the run-time system prints an error message and stops the program. Semantic error: In some [...]

There are several ways to execute a Perl program, but the most common is to put a “shebang” line at the beginning that tells the shell where to find the program called perl that compiles and executes Perl programs. #!/usr/bin/perl print @ARGV; The UNIX utility called echo takes any number of command-line arguments and prints them. Here is a perl program that does almost the same thing: print @ARGV; The program contains one print statement. [...]