Show date and arbitrarily formatted date:
date
Fri Jul 13 14:37:50 HKT 2001
date '+%j'
194
date '+%Y'
2001
date '+%D'
07/13/01
date '+%A'
Friday
date '+%b'
Jul
date '+%e-%B-%Y (%a)'
13-July-2001 (Fri)