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Loop over the days of a month, in $YYYY$MM$DD format

Terminal - Loop over the days of a month, in $YYYY$MM$DD format
YYYY=2014; MM=02; for d in $(cal -h $MM $YYYY | grep "^ *[0-9]"); do DD=$(printf "%02d" $d); echo $YYYY$MM$DD; done
2014-02-06 11:31:57
User: fibo
Functions: cal echo grep printf
Loop over the days of a month, in $YYYY$MM$DD format

Edit YYYY and MM at the beginning of the command with the year and month you want.

Note that `DD=$(printf "%02d" $d)` will pad single digit integers with a leading zero.

Substitute `echo $YYYY$MM$DD` at the end of the line with the command you want to launch, for instance

script.pl --yyyymmdd $YYYY$MM$DD

Also available on GitHub as bash util: https://github.com/fibo/yyyymmdd


There are 6 alternatives - vote for the best!

Terminal - Alternatives

Know a better way?

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What others think

Very nice.

I can offer one small improvement and one alternate way of formatting.

| tail -6 | head -5

can be replaced with grep (saving one command):

| grep "^ *[0-9]"

Some (or none) leading space, followed by numbers.

"printf" is a shell builtin so it's already quick, but the alternative bash way is:

[ ${#DD} = 1 ] && DD=0$DD

If DD has length 1, then prefix it with a zero.

So my command looks like:

YYYY=2014; MM=02; for DD in $(cal $MM $YYYY | grep "^ *[0-9]"); do [ ${#DD} = 1 ] && DD=0$DD; echo $YYYY$MM$DD; done
Comment by flatcap 218 weeks and 5 days ago

@flatcap: thank you for your improvement. I replaced the first submitted version


YYYY=2014; MM=02; for d in $(cal $MM $YYYY | tail -6 | head -5); do DD=$(printf "%02d" $d); echo $YYYY$MM$DD; done


adding grep "^ *[0-9]" as you suggested. About prefixing with leading zero, I prefer printf, so you can even change format if you want, just editing "%02d".

Comment by fibo 215 weeks and 5 days ago

Is there any way to modify this command to include the day names?



2014-02-01 SA

2014-02-02 SU

2014-02-03 MO

2014-02-04 TU

2014-02-05 WE


after looking through the commands for cal I haven't had luck myself.

Comment by banj 205 weeks ago

Your point of view

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