complete -c date -s d -l date -d "Display date described by string" -x
complete -c date -s f -l file -d "Display date for each line in file" -r
complete -c date -s I -l iso-8601 -d "Output in ISO 8601 format" -x -a "date hours minutes seconds"
complete -c date -s s -l set -d "Set time" -x
complete -c date -s R -l rfc-2822 -d "Output RFC-2822 compliant date string"
complete -c date -s r -l reference -d "display the last modification time of file" -r
complete -c date -s u -l utc -d "print or set Coordinated Universal Time"
complete -c date -l universal -d "print or set Coordinated Universal Time"
complete -c date -s h -l help -d "Display help and exit"
complete -c date -s v -l version -d "Display version and exit"