This assumes you have installed the Log::Log4perl module on your system.

The following script is an example of how to use the logger in easy mode with easy_init. In this example, Hello World will be printed to the console.

#!/usr/bin/perl
use strict;
use warnings;
use Log::Log4perl qw(:easy);

Log::Log4perl->easy_init({
    level   => $INFO,
    layout  => '%d{MMM-dd-yyyy HH:mm:ss,SSS} %-5p %m%n'
});

my $logger = Log::Log4perl->get_logger();

$logger->info("Hello World");

Running this script should output something like this.

Sep-20-2022 00:36:21,951 INFO  Hello World

And here is an example of how to use to init to load the logger using a configuration file.

#!/usr/local/bin/perl

use strict;
use warnings;
use Log::Log4perl qw(:easy);

my $conf = q(
  log4perl.logger                                         = INFO, Logfile, Screen

  log4perl.appender.Logfile                               = Log::Log4perl::Appender::File
  log4perl.appender.Logfile.filename                      = example.log
  log4perl.appender.Logfile.mode                          = append
  log4perl.appender.Logfile.size                          = 1KB
  log4perl.appender.Logfile.max                           = 5
  log4perl.appender.Logfile.DatePattern                   = yyyy-MM-dd
  log4perl.appender.Logfile.TZ                            = CST
  log4perl.appender.Logfile.layout                        = Log::Log4perl::Layout::PatternLayout
  log4perl.appender.Logfile.layout.ConversionPattern      = %d{MM-dd-yy HH:mm:ss} %-5p [%c] %m%n

  log4perl.appender.Screen                               =  Log::Dispatch::Screen
  log4perl.appender.Screen.Threshold                     =  INFO
  log4perl.appender.Screen.layout                        =  Log::Log4perl::Layout::PatternLayout
  log4perl.appender.Screen.layout.ConversionPattern      =  %d{MM-dd-yy HH:mm:ss} %-5p [%c] %m%n
);

Log::Log4perl::init(\$conf);

my $logger = Log::Log4perl->get_logger();

$logger->info("Hello World");

More commonly, you may have the configuration in it's own file, perhaps perl_logger.conf.

log4perl.logger                                         = INFO, Logfile, Screen
log4perl.appender.Logfile                               = Log::Log4perl::Appender::File
log4perl.appender.Logfile.filename                      = sub { return get_log_filename(); }
log4perl.appender.Logfile.mode                          = append
log4perl.appender.Logfile.size                          = 1KB
log4perl.appender.Logfile.max                           = 5
log4perl.appender.Logfile.DatePattern                   = yyyy-MM-dd
log4perl.appender.Logfile.TZ                            = CST
log4perl.appender.Logfile.layout                        = Log::Log4perl::Layout::PatternLayout
log4perl.appender.Logfile.layout.ConversionPattern      = %d{MM-dd-yy HH:mm:ss} %-5p [%c] %m%n
log4perl.appender.Screen                               =  Log::Dispatch::Screen
log4perl.appender.Screen.Threshold                     =  INFO
log4perl.appender.Screen.layout                        =  Log::Log4perl::Layout::PatternLayout
log4perl.appender.Screen.layout.ConversionPattern      =  %d{MM-dd-yy HH:mm:ss} %-5p [%c] %m%n

And the init the logger using the conf file.

#!/usr/local/bin/perl

use strict;
use warnings;
use Log::Log4perl qw(:easy);

Log::Log4perl::init("/path/to/perl_logger.conf");

my $logger = Log::Log4perl->get_logger();

$logger->info("Hello World");

And here is how you can have the logger append to a log file and to the console.

Log::Log4perl->easy_init(
  {
    level   => $INFO,
    layout  => "%d{MMM-dd-yyyy HH:mm:ss,SSS} %-5p %m%n",
    file    => "STDOUT"
  },
  {
    level   => $INFO,
    layout  => "%d{MMM-dd-yyyy HH:mm:ss,SSS} %-5p %m%n",
    file    => ">>/path/to/example.log"
  }
);

my $logger = Log::Log4perl->get_logger();

$logger->info("Hello World");