Introduction

Subroutines are user-created functions that execute a block of code at any given place in your program. It is a best practice, however, to aggregate them all either at the beginning or the end the main program.

Subroutine declarations initiate with the key word “sub” . Conventionally, subroutine names are all lowercase characters

sub NAME (PROTOTYPE) BLOCK

print_hello; # subroutine can be executed/called before the actual block is created

sub print_hello {
      print "Hello world\n";
}

When we called print_hello we told Perl that we wanted the piece of code named print_hello to be executed. The result is a “Hello World” showing up on our screen. The only benefit we have from that snippet in its current form is that we won’t have to copy/paste the print statement all over our script if we want to repeat it. All we need to do is call print_hello;
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