Question

I read the date from a file to a variable. The date has the format ddmmyyyy. It has to be converted to yyyy-mm-dd
I already searched this forum and got this far :
date -d ‘$DATE’ +%F
The problem is the input format is not recognised. Is there any way I can specify the input date format?
On an other forum I found : date -d “${OLD_DATE}” -D “%d%m%Y” +%F
where -D should specify the input format but this doesn’t work. But -D is unknown.

thanks for the help and sorry for my English.

Answer 1

You could to it like this:

echo "DDMMYYYY" | awk 'BEGIN {OFS="-"} {print substr($1,5,4), substr($1,3,2), substr($1,1,2)}'

Output:

YYYY-MM-DD