perl - rough template thats outputs to screen & log file

perl_template.pl

#! /usr/bin/perl

use strict;
use warnings;
use 5.010;
use Time::HiRes qw/time gettimeofday/;
use POSIX 'strftime';
use FileHandle ('autoflush');
use Getopt::Std;

my %opt;

sub usage()
{
 say "Usage = ???.pl [-v] -l <filename>";
 exit 58;
}

sub main()
{

 parse_args();
         
 say "VERBOSE ENABLED = [$opt{v}]" if $opt{v};

 say "FILE LOGGING ENABLED = [$opt{l}]" if exists $opt{l};
    
 while(1)
 {
  out("LOG TEST @ epoch " . time());
  sleep(1);
 }

}

sub parse_args()
{
 use Getopt::Std;
        
 my $opt_string = 'vhl:';  # -v=verbose // -h=help // -l = output to log file
        
 getopts( "$opt_string", \%opt ) or usage();
        
 usage() if $opt{h};
  
 if($opt{l})
 {
  if(!open(LOG,">$opt{l}")) { die "FILE ERROR" };
  LOG->autoflush(1);
 } 
}

# log to screen + if enabled log to file
sub out
{
 my $data = shift; # get the "text" to output
  
 my $msg = now() . " : PID[$$] THREAD[$$] FILENAME[$0] STARTTIME[$^T]: " . $data; # $_[0]; # prefix a timestamp
  
 say "$msg"; # to STDOUT
  
 if($opt{l}) # if enabled to FILE
 {
  say LOG "$msg";
 }
}

# a decent "datetime" string
sub now
{
 my ($epoch, $microseconds) = gettimeofday;
			
 my $now = strftime( q/%Y:%m:%d %H:%M:%S./, localtime($epoch)) . sprintf("%06d", $microseconds);
	
 return $now;
}

main();

exit 0;