perl function die

The die function in Perl is used to exit a script and print an error message to the console. Here's an example of how to use die:

my $num = 10;
if ($num > 5) {
  die "Error: \$num is too big\n";
}

print "The value of \$num is $num\n";

In this example, a variable $num is declared with a value of 10. An if statement is used to check whether $num is greater than 5. If it is, the die function is called with an error message as its argument. If $num is not greater than 5, the script continues to the next line and prints the value of $num.

If the die function is called, the script immediately exits and the error message is printed to the console. In this case, since $num is greater than 5, the output of the script is:

Error: $num is too big

It's important to note that when the die function is called, any changes made to variables or data structures in the script will be lost, since the script exits immediately. Therefore, it's a good idea to use die only when there is a fatal error that prevents the script from continuing.