I had need of a simple program that could display a calendar when I'm working on the command line. This small program fits my needs and I'm hopeful it may be useful to others.
Option | Description |
---|---|
-n # | Set the number of calendars per row when displaying a year. The default is 3. |
-D | Start in Debug Mode which will display additional debugging data. Normally not used. |
-v | Display the current version and copyright of the program and exit |
-h or -? | Display the help page |
Parameters are the arguments provided to the program. They do not include the options above.
Parameter | Description |
---|---|
Year | |
Month | |
Month Year | |
This is a java program that is all bundled into a single jar file. To run a jar file on the command line, simply type:
java -jar cal.jar
Please note that cal.jar must be in your path.
Command|Result
---|---|
java -jar cal.jar
| Display the current year
java -jar cal.jar -n 4
| Display the current year - 4 months per row
java -jar cal.jar 9
| Display September of the current year
java -jar cal.jar 2022
| Display the entire year 2022
java -jar cal.jar 9 2022
| Display September of 2022
java -jar cal.jar -D 6
| Display June of current year in debug mode
java -jar cal.jar -h
| Show this help information
I would encourage anyone with a supported Linux platform to use snap. See Snapcraft Homepage for more information. You can download, install, and keep Cal up to date automatically by installing the snap via :
sudo snap install fcal
(Assuming snap is installed)
I had to call it fcal
as cal
was already taken.
This will install the application into a sandbox where it is separate from other applications. I do want to look at packaging it via Flatpak as well, but my understanding is that Maven is not well supported. However, I need to do more investigation.
I was able to use several web pages for sources of formulas for the program. These were very helpful and I'd like to thank their authors for taking the time to record them publicly.
Determine how to calculate the first day of a month given the month and year:
* https://www.tondering.dk/claus/cal/chrweek.php#calcdow
* http://www.cplusplus.com/forum/general/174165/
Calculate if the year provided is a leap year:
* https://www.wikihow.com/Calculate-Leap-Years
Copyright (C) 2019 by Michael Fross
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