Today's date, minus X days in shell script

Question

I need to create three variables, each for Year, Month, and Day for Today\'s date, minus X number of days. For this question I\'ll choose a random amount of days: 222.

Answer 1

epoch=$(( `date '+%s'` - ( 24 * 60 * 60 * 222 ) ))
year=`date -d "@$epoch" '+%Y'`
month=`date -d "@$epoch" '+%m'`
day=`date -d "@$epoch" '+%d'`

Should do the trick.