How to generate date range for random data on bash

Question

I need to generate strings with all days in a year

ex:

MIN_DATE=01.01.2012

MAX_DATE=31.12.2012

for date in {1...366..1}
 do
 echo ...
done

score 12 · Answer 1 · answered Aug 24 '12 at 10:25

12

for d in {0..365}; do date -d "2012-01-01 + $d days" +'%d.%m.%Y'; done

answered Aug 24 '12 at 10:25

Lev Levitsky

63,701
20
147
175

how to do this automatically with leak years? – Dmitry Dubovitsky Aug 24 '12 at 11:03
@DmitryDubovitsky What do you mean? `29.02.2012` is present in the output. – Lev Levitsky Aug 24 '12 at 11:05
Want to output it automatically, for example For 2011 year last record would be 2012-01-01 something that: `days_in_year=date "2012-12-31" +"%j"; for d in in ...` – Dmitry Dubovitsky Aug 24 '12 at 11:52
@DmitryDubovitsky Ah, I get it now. Well, I'd just do: `for d in {0..365}; do date -d "$year-01-01 + $d days" +'%d.%m.%Y'; done | grep $year`. That'll work whether `year` is 2011 or 2012. – Lev Levitsky Aug 24 '12 at 11:56
1

This is not working in OS X since it uses a different version of `date`. – Fábio Perez Dec 19 '13 at 23:27

score 2 · Answer 2 · answered Aug 24 '12 at 12:43

2

Not a pure bash solution, but my dateutils can help:

dseq 01.01.2012 31.12.2012 -f %d.%m.%Y -i %d.%m.%Y
=>
  01.01.2012
  02.01.2012
  ...
  31.12.2012

Output format can be configured with -f and input format with -i.

answered Aug 24 '12 at 12:43

hroptatyr

4,702
1
35
38

score 1 · Answer 3 · answered Aug 24 '12 at 12:47

1

Using an ISO 8601 date format (year-month-day), you can compare dates lexicographically. It's a little messier than I'd like, since bash doesn't have a "<=" operator for strings.

year=2011
d="$year-01-01"
last="$(($year+1))-01-01"
while [[ $d < $last ]]; do
    echo $d
    d=$(date +%F --date "$d + 1 day")
done

answered Aug 24 '12 at 12:47

chepner

497,756
71
530
681

Comparing years lexicographically is a bad idea if your years can have a different number of digits. For example `d="999-01-01"; last="1000-01-01"` will produce no output. – Boris Verkhovskiy Aug 30 '19 at 06:35
1

ISO-8601 requires at least 4 digits for the year (although the problem will arise if you are trying to avoid a Y10k problem). – chepner Aug 30 '19 at 12:34

How to generate date range for random data on bash

3 Answers3

Linked