https://github.com/mountaineerbr/shelldatediff
Calculate time differences with Ksh, Bash, and Zsh builtins. Check moon phases, Easter dates and next Friday 13th.
https://github.com/mountaineerbr/shelldatediff
bash datediff easter-date friday-13th friday13th ksh lunar-phases moon-phase script shell time zsh
Last synced: 2 months ago
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Calculate time differences with Ksh, Bash, and Zsh builtins. Check moon phases, Easter dates and next Friday 13th.
- Host: GitHub
- URL: https://github.com/mountaineerbr/shelldatediff
- Owner: mountaineerbr
- License: gpl-3.0
- Created: 2023-02-10T03:15:08.000Z (over 2 years ago)
- Default Branch: main
- Last Pushed: 2025-01-14T14:38:13.000Z (4 months ago)
- Last Synced: 2025-01-25T17:32:58.257Z (4 months ago)
- Topics: bash, datediff, easter-date, friday-13th, friday13th, ksh, lunar-phases, moon-phase, script, shell, time, zsh
- Language: Shell
- Homepage:
- Size: 231 KB
- Stars: 0
- Watchers: 0
- Forks: 0
- Open Issues: 0
-
Metadata Files:
- Readme: README.md
- License: LICENSE
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README
# shellDatediff
Calculate time differences with Ksh, Bash and Zsh built-ins.
The project contains a small shell library to calculate elapsed time
between two dates in various time units and some extra functions for
day-to-day use.
Results are delivered in different units taking into account all time
units (*compound time range*), or as a fractional single time unit.
The script warps `GNU`/`BSD` `C-code date` programme to process input
date strings in various formats (main function), otherwise
input must be *ISO-8601* or *UNIX* times.
## ✨ Features
- Date input as *ISO-8601*, or *UNIX times*. Optionally, warps `C-code date`.
- Date offset aware, heeds environment `$TZ`
- Check whether year is leap
- Check moon / lunar phases
- Check Easter, Carnaval, and Corpus Christi dates
- Check for next Friday the 13th
- Get input from _stdin_
## Usage Examples
### Time elapsed from *January 15th, 2008* to *now*
```
% datediff.sh -u 2008-01-15
DATES-
2008-01-15T00:00:00+00:00 1200355200
2024-09-11T16:15:34+00:00 1726071334
RANGES
16Y 07M 03W 06D 16h 15m 34s
16.7 years | 376.6 months | 869.2 weeks | 6084.7 days | 146032.3 hours | 8761935.6 mins | 525716134 secs
```
When only one date is specified, the first date is assumed to be *now* or *1970*.
Note that `option -u` sets dates as UTC time and it influences how the underlying `C-code date` programme works.
Setting the last argument of the command line to exactly `y`, `mo`, `w`, `d`, `m`, or `s` will print only the specified time frame result.
Alternatively, set `options -vvv` to filter the main output layout for specific fields.
For example, print the **compound time range** _only_:
```
% datediff.sh -vv tomorrow+6years+400hours+12seconds
6Y 00M 02W 03D 16h 00m 12s
```
To test the shell built-in code for the ISO-8601 and UNIX times tamp processing and conversion
without wrapping the `C-code date` programme, set `options -DD`.
### Result layout
The main function is very verbose by defaults and
prints two sections with processed dates (**DATES**) and time range results (**RANGES**).
The user can filter out which fields are going to be calculated and printed.
Set the verbose `option -v` up to three times to select different layouts in
the main function. Setting `-v` in other functions decrease verbose.
All single unit results _only_:
```
% datediff.sh -v 2008-01-15
16.8 years | 378.8 months | 879.0 weeks | 6152.9 days | 147669.4 hours | 8860165.2 mins | 531609914 secs
```
Compound time range (`AST date` style):
```
% datediff.sh -vvv 2008-01-15
16Y10M00W03D21h25m34s
```
### Single time unit result
The user can optionally set the last positional parameter as exactly
`y`, `mo`, `w`, `d`, `m` or `s` to print only the specific single-unit result:
```
% datediff.sh 2008-01-15 mo
378.8 months
```
### Decimal plates
The number of decimal plates shown in float results can be set with `options -[num]`,
where _num_ is an integer. For three decimal plates, the incantation should start as
`datediff.sh -3`.
Results are subject to rounding for improved precision!
### Table view
There is also a table layout with single-unit results. This is activated with
`option -t`.
To **print results in the table layout**, set `options -tt`
at the command line incantation:
```
% datediff.sh -3 -t 2008-01-15
Years 16.915
Months 379.704
Weeks 882.690
Days 6178.831
Hours 148291.953
Mins 8897517.150
Secs 533851029
```
### Check when next *Friday the 13th* is
```
% datediff.sh -F Fri 13
Fri, 13 Oct 2023 is 245 days away
```
Set `options -FF` to get the next 10 dates.
### Check whether a year *is leap*
```
% datediff.sh -l 2023
not leap year -- 2023
```
The exit code is *1* if a year _is_ _not_ leap.
Set `option -v` to decrease verbose.
### Generate the *lunar phase calendar*
```
% datediff.sh -m 2023-02
2023-02-01 First Quarter
2023-02-02 Waxing Gibbous
2023-02-06 Full Moon
2023-02-09 Waning Gibbous
2023-02-13 Last Quarter
2023-02-17 Waning Crescent
2023-02-20 New Moon
2023-02-24 Waxing Crescent
2023-02-28 First Quarter
```
Also try `datediff.sh -m 2024-{02..12}` for multiple months!
### Print dates of *Carnaval*, *Easter* and *Corpus Christi*
```
% datediff.sh -ee 2023
Carnaval Easter CorpusChristi
2023-02-21 2023-04-09 2023-06-08
```
Set multiple years to get a nice `TSV`-formatted output.
The dates are for the Western Church.
## Requirements
- `Ksh93`, `Bash`, or `Zsh`
- `GNU`/`BSD`/`AST`/`Busybox` `date` (optional)
- `Bc` and `Dc` (optional)
## Help
Please, check script help page with `datediff.sh -h`
or the [online man page](man/README.md).
## Project Source
- GitLab
- GitHub
Extensively tested, see [testing scripts](tests/), [notes](tests/d-test.sh#L78-L186), and [man page](man/README.md).
## See Also
- C-code `dateutils/datediff`, *Hroptatyr*, .
- Python `PDD`, *Jarun*, .
- *AST* `date`, see elapsed time _option_ _-E_, .
- *GNU* `units`, .
- \`\`Calendrical calculation'', *Dershowitz* and *Reingold*, 1990, .