Simple stupid forking in perl. Or starting a process separate from your perl script or app tutorial.

I was trying to get a program to start independently from my perl script, and was having a little difficulty today until I found this page which breaks it down pretty simple, however I am going to break it down a little farther for people like me who are pretty duh huh without explicit instructions.
This is from the page above:

if($pid = fork){
# Parent
command;
}elsif($pid == 0){
# Child
command;
# The child must end with an exit!!
exit;
}else{
# Error
die "Fork did not work\n";
}

So in itself it's pretty self explanatory, however you could have some problems if you don't explicitly declare $pid. But besides that you can literally just plug your commands in where it says command;. So maybe I was making it out harder than it was supposed to be, but anyway haves fun. Oh and here's a stupid simple example:


use strict;

my $pid;
if($pid = fork){
# Parent
system("calc");
}elsif($pid == 0){
# Child
system("notepad");
# The child must end with an exit!!
exit;
}else{
# Error
die "Fork did not work\n";
}

system("notepad");


Ok so what's this do. Well it starts calc as part of the parent program, then it starts notepad, once you close the program it will continue on to start a new notepad...so what's the difference between starting it this way and doing it this way:

system("calc");
system("notepad");
system("notepad");

Well without spawning a child process using for you will simply open calc, and once it is closed notepad is opened. Then when you close notepad, another notepad will open.