#!ruby -nlrdate
~/ /
d=Date.parse"#$'-#$`-1"
puts d.strftime('%B %Y').center(20),'Su Mo Tu We Th Fr Sa',(0..5).map{|i|[*(['  ']*d.wday+(d...d>>1).map{|x|'%2s'%x.day})[i*7,7]]*' '}