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Man Pages

Manual Reference Pages  -  WHEN (1)

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When - a minimalistic personal calendar program




when [options] [commands]

The basic idea is just to type ‘when’ at the command line. The first time you run the program, it will prompt you for some setup information. To edit you calendar file in your favorite editor, do ‘when e’. The basic format of the calendar file is like this:

        2003 feb 3 , Fly to Stockholm to accept Nobel Prize.

Once you have a calendar file, running the program as plain old ‘when’ from the command line will print out the things on your calendar for the next two weeks.


i Print upcoming items on your calendar. (This is the default command.)
c Print calendars (grids like on a wall calendar, not showing items) for last month, this month, and next month.
e Invoke your favorite editor to edit your calendar file.
w,m,y Print items for the coming week, month, or year, rather than for the default period of two weeks.
j Print the modified Julian day (useful for finding the time interval between two dates).
d Print nothing but the current date.


All of the following options, except --help, can be set in the preferences file. True/false options can be set on the command line as --option or --nooption, and in the preferences file by setting the option to 0 or 1.
--help Prints a brief help message.
--version Prints a brief message, including a statement of what version of the software it is.
--language=LANG Set the language to LANG. See the section below on internationalization. This option is not normally needed, because the language is automatically detected.
--future=DAYS How many days into the future the report extends. Default: 14
--past=DAYS How many days into the past the report extends. Like the --future option, --past is interpreted as an offset relative to the present date, so normally you would want this to be a negative value. Default: -1
--calendar=FILE Your calendar file. The default is to use the file pointed to by your preferences file, which is set up the first time you run When.
--editor=COMMAND Command used to invoke your editor. Default: emacs -nw Example: when --editor=vim
--wrap=COLUMNS Number of columns of text for the output (or 0 if you don’t want wrapping at all). Default: 80
--[no]wrap_auto Attempt to detect the width of the terminal, and set the width of the output accordingly. This applies only if the output is a tty, and is subject to any maximum set by --wrap_max. Overrides any value set by --wrap. Default: no
--wrap_max=COLUMNS Maximum number of columns of text for the output (or -1 if you don’t want any maximum). Useful in combination with --wrap_auto to preserve legibility on very large terminal windows. Default: -1
--rows=COLUMNS Number of rows of text that will fit in the terminal window. When listing your calendar, output will be truncated to this length, unless that would result in listing less than three days into the future. This behavior is overridden (the maximum number of rows is set to infinity) if the --future option is given explicitly, or if the m or y command is used. Default: 40
--[no]rows_auto Attempt to detect the height of the terminal, rather than using the value set in the --rows option. This applies only if the output is a tty. Overrides any value set by --rows. Default: yes
--[no]header Print headers at the top of the output of the i, c, w, m and y commands. Default: yes
--[no]paging When the output is longer than the value set by rows or rows_auto, use a pager to display the output. (The PAGER and LESS environment variables are respected. If PAGER isn’t set, the default is less.) Default: yes
--paging_less_options Extra options if the pager is less. Default: -rXFE
--[no]filter_accents_on_output Whether to change accented characters to unaccented ones. Default: yes, unless the $TERM environment variable equals mlterm or xterm.
--[no]styled_output If the output is a terminal, should we use ANSI terminal codes for styling? Default: yes
--[no]styled_output_if_not_tty Style the output even if it’s not a terminal. Default: no
--items_today_style=STYLE The first of these says how to style today’s date when doing the calendar (c) command. The second says how to style the word ‘‘today’’ when doing the items (i) command. Defaults: bold

The styling of output can be specified using the following keywords: bold, underlined, flashing. To change the color of the text, use these: fgblack, fgred, fggreen, fgyellow, fgblue, fgpurple, fgcyan, fgwhite. To change the background color, use similar keywords, but with bg instead of fg. Example: when --calendar_today_style=bold,fgred,bgcyan c

--prefilter Pipe the calendar file through a program before reading it. Default: ""
--now=‘‘Y M D’’ Pretend today is some other date.
--[no]neighboring_months The default behavior of when c is to print out calendars for last month, this month, and next month. By choosing --noneighboring_months, you can avoid printing out months not included in the range set by --past and --future.
--[no]monday_first Start the week from Monday, rather than Sunday. Default: no
--[no]orthodox_easter Calculate Easter according to the Orthodox Eastern Church’s calendar. Default: no
--[no]ampm Display the time of day using 12-hour time, rather than 24-hour time. Also affects the parsing of input times. Default: yes
--auto_pm=x When times are input with hours that are less than x, and AM or PM is not explicitly specified, automatically assume that they are PM rather than AM. Default: 0
--[no]literal_only Only display items that are given as literal dates, e.g., 2008 jul 4. Don’t display items that are defined by expressions, e.g., periodic items like w=thu. Default: no
--test_accent_filtering These options are used internally for building and testing.


When is an extremely simple personal calendar program, aimed at the Unix geek who wants something minimalistic. It can keep track of things you need to do on particular dates. There are a lot of calendar and ‘‘personal information manager’’ programs out there, so what reasons are there to use When?
It’s a very short and simple program, so you can easily tinker with it yourself.
It doesn’t depend on any libraries, so it’s easy to install. You should be able to install it on any system where Perl is available, even if you don’t have privileges for installing libraries.
Its file format is a simple text file, which you can edit in your favorite editor.
Although When should run on virtually any operating system where Perl is available, in this document I’ll assume you’re running some flavor of Unix.


While logged in as root, execute the following command:

       make install

Run When for the first time using this command:


You’ll be prompted for some information needed to set up your calendar file.


If you run When again after the initial setup run, it should print out a single line of text, telling you the current date. It won’t print out anything else, because your calendar file is empty, so you don’t have any appointments coming up.

Now you can start putting items in your calendar file. Each item is a line of text that looks like this:

        2003 feb 3 , Fly to Stockholm to accept Nobel Prize.

A convenient way to edit your calendar file is with this command:

        when e

This pops you into your favorite editor (the one you chose when you ran When for the first time).

The date has to be in year-month-day format, but you can either spell the month or give it as a number. (Month names are case-insensitive, and it doesn’t matter if you represent February as F, Fe, Feb, Februa, or whatever. It just has to be a unique match. You can give a trailing ., which will be ignored. In Czech, cer can be used as an abbreviation for Cerven, and cec for Cervenec.) Extra whitespace is ignored until you get into the actual text after the comma. Blank lines and lines beginning with a # sign are ignored.

If you now run When, it will print out a list of all the items in your calendar file that fall within a certain time interval. (The interval starts from yesterday. When tries to pick the end of the time interval so that its output fits on your terminal window, but it will always be at least three days, and no more than two weeks in the future.) To see all your items for the next month, do ‘‘when m’’, and similarly for a year, y, or a single week, w.

If you do ‘‘when c’’, When prints out calendars for last month, this month, and next month.

You can combine these commands. For instance, ‘‘when cw’’ will print out calendars, and then show you your items for the next week.

For events that occur once a year, such as birthdays and annivesaries, you can either use a * in place of the year,

        * dec 25 , Christmas

or use a year with an asterisk:

        1920* aug 29 , Charlie Parker turns \a, born in \y

In the second example, \a tells you how old Charlie Parker would be this year, and \y reproduces the year he was born, i.e., the output would be:

        today     2003 Aug 29 Charlie Parker turns 83, born in 1920

For things you have to do every week, you can use an expression of the form w=xxx, where xxx is the first few letters of the name of the day of the week in your language. (You have to supply enough letters to eliminate ambiguity, e.g., in English, w=th or w=tu, not just w=t.) Example:

        w=sun , go to church, 10:00

You can actually do fancier tests than this as well; for more information, see the section ’fancy tests’ below. Here’s how to set up some common holidays:

        m=jan & w=mon & a=3 , Martin Luther King Day
        * feb 14 , Valentines Day
        m=feb & w=mon & a=3 , Washingtons Birthday observed
        m=may & w=sun & a=2 , Mothers Day
        m=may & w=mon & b=1 , Memorial Day
        m=jun & w=sun & a=3 , Fathers Day
        * jul 4 , Independence Day
        m=sep & w=mon & a=1 , Labor Day
        m=oct & w=mon & a=2 , Columbus Day
        m=oct & w=mon & a=2 , Thanksgiving (Canada)
        * nov 11 , Armistice Day
        m=nov & w=thu & a=4 , Thanksgiving (U.S.)
        e=47 , Mardi Gras
        e=46 , Ash Wednesday
        e=7 , Palm Sunday
        e=0 , Easter Sunday       
        e=0-49 , Pentecost (49 days after easter)

In the U.S., when certain holidays fall on a weekend, federal workers, as well as many private employees, get a Monday or Friday off. The full list is given at If you want a reminder of both the holiday and the day you get off from work, here’s an example of how you would set that up:

        * jul 4 , Independence Day
        m=jul & c=4 , Independence Day (observed as a federal holiday)


When has at least partial support for Czech, Danish, Dutch, English, French, German, Greek, Hungarian, Italian, Polish, Romanian, and Spanish. If When has not been translated into your language, or has only been partially translated, the text that hasn’t been translated will be displayed in English. When should automatically detect what language you use (via your $LANG environment variable), and if When has been translated into that language, that’s what you’ll get — When’s output will be in your language, and When will also expect you to use that language in your calendar file for the names of the months and the days of the week.

Your calendar file must be in UTF-8 (or ASCII, which is a subset of UTF-8). If your calendar file is in some other encoding, such as ISO-8859, When will typically be able to detect that, and will refuse to read it. Command-line options can also contain UTF-8.

Some terminal emulators (aterm, ...) display accented characters as garbage, but others (mlterm, xterm...) can display them correctly. When checks the $TERM environment variable, and if it equals mlterm or xterm, then accented characters will be displayed. Otherwise, they are filtered out of the output. You can override this by putting a line like

        filter_accents_on_output = 0


        filter_accents_on_output = 1

in your ~/.when/preferences file. I’d be interested in hearing from any users who can suggest a better mechanism for this than attempting to interpret the $TERM variable.

On input, accents are allowed, but not required, e.g., in a French-language input file, the date 2005 Fev 17 could be given with an accented e or an unaccented one, and either will work. If an input month or day of the week does not match any of the ones for your language, then When will try to interpret it as English instead.

You can put a line like

        language = fr

in your preferences file to set your language, or supply the --language option on the command line, but that’s not necessary if your $LANG environment variable is set correctly.


Each line consists of something like this:

        variable = value

Whitespace is ignored everywhere except inside the value. Variable names are case-insensitive. Blank lines are ignored.


A useful command to have your shell execute when you log in is this:

        when --past=0 --future=1

To print out a calendar for a full year to come:

        when --past=0 --future=365 c


Your calendar doesn’t do you any good if you forget to look at it every day. An easy way to make it pop up when you log in is to make your .xsession or .xinitrc file look like this:

        /usr/bin/when --past=0 --future=1 &>~/
        emacs -geometry 70x25 -bg bisque ~/ &

The .xsession file is used if you have a graphical login manager set up on your machine, the .xinitrc if you don’t. In this example, the first line outputs your calendar to a file. The complete path to the When program is given, because your shell’s path variable will not yet be properly initialized when this runs. The second line pops up a GUI emacs window, which is distinctively colored so that it will catch your eye. The last line starts your window manager, KDE in this example. Whatever window manager you use, just make sure to retain the preexisting line in the file that starts it, and make sure that that line is the very last one in the file.


If you want the various items that lie on a single day to be printed out in a certain order, the simplest way to do it is to put them in that order in the input file. That method won’t work, however, when some of the items lie on dates that are determined by expressions rather than given explicitly. The most common reason for wanting to do this kind of thing is that you have things you need to do at certain times during the day, and you want them sorted out by time. In this situation, you can give a time at the beginning of the item’s text, and When will recognize that and sort the items by time. Times can be in h:mm or hh:mm format. If --ampm is set, then an optional suffix a or p can be used for AM or PM, e.g., 9:30a for 9:30 AM. If you use AM/PM time, then you can also, e.g., set --auto_pm=9 so that hours less than 9 are automatically assumed to be PM. Here is an example:

        2010 apr 25 , 7:00 dinner at the anarcho-syndicalist commune
        w=sun , 10:00 church

April 25, 2010 is a Sunday, so on that date both of these items will be displayed. If --auto_pm is set to 8 or higher, then the 7:00 will automatically be interpreted as 7:00 PM, and the dinner date will be displayed below the morning church ceremony.


In addition to w, discussed above, there are a bunch of other variables you can test:

        w  -  day of the week
        m  -  month
        d  -  day of the month
        y  -  year
        j  -  modified Julian day number
        a  -  1 for the first 7 days of the month, 2 for the next 7, etc.
        b  -  1 for the last 7 days of the month, 2 for the previous 7, etc.
        c  -  on Monday or Friday, equals the day of the month of the nearest weekend day; otherwise -1
        e  -  days until this years (Western) Easter
        z  -  day of the year (1 on New Years day)

You can specify months either as numbers, m=2, or as names in your language, m=feb. You can also use the logical operators & (and) and | (or). The following example reminds you to pay your employees on the first and fifteenth day of every month:

        d=1 | d=15 , Pay employees.

This example reminds you to rehearse with your band on the last Saturday of every month:

        w=sat & b=1 , Rehearse with band.

The following two lines

        * dec 25 , Christmas
        m=dec & d=25 , Christmas

both do exactly the same thing, but the first version is easier to understand and makes the program run faster. (When you do a test, When has to run through every day in the range of dates you asked for, and evaluate the test for each of those days. On my machine, if I print out a calendar for a whole year, using a file with 10 simple tests in it, it takes a few seconds.) Parentheses can be used, too.

Depending on your nationality and religion, you probably have a bunch of holidays that don’t lie on fixed dates. In Christianity, many of these (the movable feasts) are calculated relative to Easter Sunday, which is why the e variable is useful.

There is a not operator, !:

        w=fri & !(m=dec & d=25) , poker game

There is a modulo operator, %, and a subtraction operator, -. Using these, along with the j variable, it is just barely possible for When’s little parser to perform the following feat:

        !(j%14-1) , do something every other Wednesday

The logic behind this silly little piece of wizardry goes like this. First, we determine, using the command ‘when j --now=2005 jan 26’, that the first Wednesday on which we want to do this has a Julian day that equals 1, modulo 14. Then we write this expression so that if it’s a Wednesday whose Julian day equals 1, modulo 14, the quantity in parentheses will be zero, and taking its logical negation will yield a true value.

The operators’ associativity and order of priority (from highest to lowest) is like this:

        left    %
        left    -
        left    < > <= >=
        left    = !=
        right   !
        left    &
        left    |


If your calendar file gets too large, you may prefer to split it up into smaller chunks — perhaps one for birthdays, one for Tibetan holidays, etc. An easy way of accomplishing this is to install the program m4, put the line

        prefilter = m4 -P

in your preferences file, and then put lines in your calendar file like this:



$LANG to automatically detect the user’s language

$TERM to try to figure out if the terminal emulator can display accented characters


$HOME/.when/calendar - The default location for the user’s calendar (pointed to by the preferences file)

$HOME/.when/preferences - The user’s preferences.


When’s web page is at


where you can always find the latest version of the software. There is a page for When on Freshmeat, at


where you can give comments, rate it, and subscribe to e-mail announcements of new releases.


When was written by Ben Crowell, Dimiter Trendafilov wrote the new and improved parser for date expressions.


Copyright (C) 2003-2012 by Benjamin Crowell.

When is free software; you can redistribute it and/or modify it under the terms of the GPL, or, optionally, Perl’s license.

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1.1.31 WHEN (1) 2013-03-17

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