Mastodawn

Just a gentle reminder to go have a nice day at the park this July 4th ;)
(We won't have another Saturday July 4th for 11 years)

rld@Intrepid:~$ for x in {1970..2099}; do cal july $x |grep -q "^ *1  2  3  4 *$" && echo $x; done
1970
1981
1987
1992
1998
2009
2015
2020
2026
2037
2043
2048
2054
2065
2071
2076
2082
2093
2099
rld@Intrepid:~$

#Chicago #SaturdayInThePark

cc: @amin

P.S., interestingly, it follows a repeating pattern of 11, 6, 5, 6:

rld@Intrepid:~$ y=0; for x in 1970 1981 1987 1992 1998 2009 2015 2020 2026 2037 2043 2048 2054 2065 2071 2076 2082 2093 2099; do ((y!=0)) && echo $((x-y)); y=$x; done
11
6
5
6
11
6
5
6
11
6
5
6
11
6
5
6
11
6
rld@Intrepid:~$

It seems that's the pattern for all repeating calendars. I tried the same with January, and it had the same pattern.

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Tim Chase Mar 26

@rl_dane

Can simplify the grep to

… | grep -q ' 4 *$'

since Saturday is the last day in the default cal(1) output 😉

And the 11/6/5/6 pattern _should_ hold until the next time we cross a century boundary when we hit the next exception to Leap Year.

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europlus

Mar 26

@gumnos @rl_dane you only need 14 distinct calendars, they repeat in a 28 year cycle which changes by a day in 2100, 2200, 2300, but 2300-2499 maintain the 28 year pattern started 2300 (same as 1900-2099).

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europlus

@gumnos @rl_dane Lifted from Enc. Britannica, drawn in MacDraw in mid 1980s. helps you determine day of week of any day from 0CE to 2399CE (and beyond, it just keeps repeating the 400 year cycle).

Look up the year in upper part - e.g. 2026 is dominical letter D.

Look at the month and go across till you hit the domninical letter. March is first column for D.

The order of days for that month are below the dominical letter for a month, So March 2026 starts on a Sunday (✔).

You can then see that 27 March is a Friday.

The large almanac-y/single volume Webster’s (I think) Encyclopaedia we had had a set of the 14 calendars and a chart to show which one to use in a given year.

This was mostly for determining day/date relationship.

I plan to extract these and other old files of mine to put online on one of my sites and IA.

Hah, while much less high-brow than encyclopedia sets, growing up we had the 14 calendars in our phonebook (remember those? I'm guessing somebody failed to sell sufficient advertising and was unsure what to do with the extra page 😆)

I'm so here for #System7 screenshots!!

Also 1262 x 1586 ?!?