• date MMDDhhmm[.ss]

$ date "+%Y-%m-%d %H:%M:%S"
2013-10-24 10:40:12

$ date "+%F %T"
2013-10-24 10:40:12

$ date "+%F %T %Z"
2013-10-24 10:40:12 CEST

DATUM=$(date --date="-1 day" "+%Y-%m-%d")

*[[https://www.cyberciti.biz/tips/linux-unix-get-yesterdays-tomorrows-date.html|Weitere Beispiele]]