MAN page from RedHat EL 8 perl-Log-Log4perl-1.50-1.el8.noarch.rpm


Section: User Contributed Perl Documentation (3)
Updated: 2020-07-22


Log::Log4perl::DateFormat - Log4perl advanced date formatter helper class 


      # Either in a log4j.conf file ...    log4perl.appender.Logfile.layout = \        Log::Log4perl::Layout::PatternLayout    log4perl.appender.Logfile.layout.ConversionPattern = %d{MM/dd HH:mm} %m      # ... or via the PatternLayout class ...    use Log::Log4perl::Layout::PatternLayout;    my $layout = Log::Log4perl::Layout::PatternLayout->new(        "%d{HH:mm:ss,SSS} %m");      # ... or even directly with this helper class:    use Log::Log4perl::DateFormat;    my $format = Log::Log4perl::DateFormat->new("HH:mm:ss,SSS");    my $time = time();    print $format->format($time), "\n";        # => "17:02:39,000"


"Log::Log4perl::DateFormat" is a helper class for the advanced date formatting functions in "Log::Log4perl::Layout::PatternLayout",and adheres (mostly) to the log4j SimpleDateFormat spec available on

It supports the following placeholders:

    Symbol Meaning              Presentation    Example    ------ -------              ------------    -------    G      era designator       (Text)          AD    e      epoch seconds        (Number)        1315011604    y      year                 (Number)        1996    M      month in year        (Text & Number) July & 07    d      day in month         (Number)        10    h      hour in am/pm (1~12) (Number)        12    H      hour in day (0~23)   (Number)        0    m      minute in hour       (Number)        30    s      second in minute     (Number)        55    S      millisecond          (Number)        978    E      day in week          (Text)          Tuesday    D      day in year          (Number)        189    F      day of week in month (Number)        2 (2nd Wed in July)    w      week in year         (Number)        27    W      week in month        (Number)        2    a      am/pm marker         (Text)          PM    k      hour in day (1~24)   (Number)        24    K      hour in am/pm (0~11) (Number)        0    z      time zone            (Text)          Pacific Standard Time    Z      RFC 822 time zone    (Text)          -0800    '      escape for text      (Delimiter)    ''     single quote         (Literal)       '    Presentation explanation:    (Text): 4 or more pattern letters--use full form, < 4--use short or             abbreviated form if one exists.     (Number): the minimum number of digits. Shorter numbers are               zero-padded to this amount. Year is handled               specially; that is, if the count of 'y' is 2, the               Year will be truncated to 2 digits.     (Text & Number): 3 or over, use text, otherwise use number.

For example, if you want to format the current Unix time in "MM/dd HH:mm"format, all you have to do is specify it in the %d{...} section of thePatternLayout in a Log4perl configuration file:

    # log4j.conf    # ...    log4perl.appender.Logfile.layout = \        Log::Log4perl::Layout::PatternLayout    log4perl.appender.Logfile.layout.ConversionPattern = %d{MM/dd HH:mm} %m

Same goes for Perl code defining a PatternLayout for Log4perl:

    use Log::Log4perl::Layout::PatternLayout;    my $layout = Log::Log4perl::Layout::PatternLayout->new(        "%d{MM/dd HH:mm} %m");

Or, on a lower level, you can use the class directly:

    use Log::Log4perl::DateFormat;    my $format = Log::Log4perl::DateFormat->new("MM/dd HH:mm");    my $time = time();    print $format->format($time), "\n";

While the "new()" method is expensive, because it parses the formatstrings and sets up all kinds of structures behind the scenes, followup calls to "format()" are fast, because "DateFormat" willjust call "localtime()" and "sprintf()" once to return the formatteddate/time string.

So, typically, you would initialize the formatter once and then reuseit over and over again to display all kinds of time values.

Also, for your convenience, the following predefined formats are available, just as outlined in thelog4j spec:

    Format   Equivalent                     Example    ABSOLUTE "HH:mm:ss,SSS"                 "15:49:37,459"    DATE     "dd MMM yyyy HH:mm:ss,SSS"     "06 Nov 1994 15:49:37,459"    ISO8601  "yyyy-MM-dd HH:mm:ss,SSS"      "1999-11-27 15:49:37,459"    APACHE   "[EEE MMM dd HH:mm:ss yyyy]"   "[Wed Mar 16 15:49:37 2005]"

So, instead of passing


you could just as well say


and get the same result later on. 

Known Shortcomings

The following placeholders are currently not recognized, unlesssomeone (and that could be you :) implements them:

    F day of week in month    w week in year     W week in month    k hour in day     K hour in am/pm    z timezone (but we got 'Z' for the numeric time zone value)

Also, "Log::Log4perl::DateFormat" just knows about English week andmonth names, internationalization support has to be added. 

Millisecond Times

More granular timestamps down to the millisecond are also supported,just provide the millsecond count as a second argument:

    # Advanced time, resultion in milliseconds    use Time::HiRes;    my ($secs, $msecs) = Time::HiRes::gettimeofday();    print $format->format($secs, $msecs), "\n";        # => "17:02:39,959"


Copyright 2002-2016 by Mike Schilli <> and Kevin Goess <>.

This library is free software; you can redistribute it and/or modifyit under the same terms as Perl itself. 


Please contribute patches to the project on Github:

Send bug reports or requests for enhancements to the authors via our

MAILING LIST (questions, bug reports, suggestions/patches):

Authors (please contact them via the list above, not directly):Mike Schilli <>,Kevin Goess <>

Contributors (in alphabetical order):Ateeq Altaf, Cory Bennett, Jens Berthold, Jeremy Bopp, HuttonDavidson, Chris R. Donnelly, Matisse Enzer, Hugh Esco, AnthonyFoiani, James FitzGibbon, Carl Franks, Dennis Gregorovic, AndyGrundman, Paul Harrington, Alexander Hartmaier David Hull, Robert Jacobson, Jason Kohles, Jeff Macdonald, Markus Peter, Brett Rann, Peter Rabbitson, Erik Selberg, Aaron Straup Cope, Lars Thegler, David Viner, Mac Yang.



Known Shortcomings
Millisecond Times

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