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.
Command Line Options
| 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. |
| -h or -? | Display the help page |
Parameters
Parameters are the arguments provided to the program. They do not include the options above.
| Parameter | Description |
|---|---|
| Year | |
| Month | |
| Month Year | |
Execution
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.
Examples
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
** License **
The MIT License
Copyright 2019-2020 by Michael Fross
Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the "Software"), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions:
The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.
THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
References
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