use Log::Log4perl qw(:easy);

$conf = <<EOT;
log4perl.rootLogger = DEBUG, Log1
log4perl.appender.Log1 = Log::Log4perl::Appender::File
log4perl.appender.Log1.filename = /tmp/test.log
log4perl.appender.Log1.mode = append
log4perl.appender.Log1.layout = Log::Log4perl::Layout::SimpleLayout
log4perl.appender.Log1.Threshold = INFO

log4perl.logger = TRACE, Log2
log4perl.appender.Log2 = Log::Log4perl::Appender::ScreenColoredLevels
log4perl.appender.Log2.layout = Log::Log4perl::Layout::PatternLayout
log4perl.appender.Log2.layout.ConversionPattern = %m%n

log4perl.category = DEBUG, Buffer
log4perl.appender.Buffer = Log::Log4perl::Appender::Buffer
log4perl.appender.Buffer.appender = Log1
log4perl.appender.Buffer.trigger_level = ERROR
EOT

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

TRACE("message #1 (screen only)");
INFO("message #2");
INFO("message #3");
sleep(10);
ERROR("message #4");

##</code><code>##

message #2
message #3
message #4

##</code><code>##

INFO - message #2
INFO - message #3
INFO - message #2
INFO - message #3
ERROR - message #4
ERROR - message #4