DATE Linux

#Function to sum DAYS to TODAY
function DATEC() { date -d @$(expr $(date +"%s" ) + $(D2S $1) ) +"%Y-%m-%d" ; }

#Function to get the number os seconds in the number o supplied days
function D2S() { expr $1 \* $( expr 24 \* $(expr 60 \* 60)) ; }

$ DATEC 0
2025-01-16

$ DATEC 1
2025-01-17

$ DATEC 100
2025-04-26

$ DATEC $(expr 100 + 50)
2025-06-15