> perl -de0

  DB<38> use Time::Piece 

  DB<39> x Time::Piece::day_list
0  'Sun'
1  'Mon'
2  'Tue'
3  'Wed'
4  'Thu'
5  'Fri'
6  'Sat'
  DB<40> x @{Time::Piece::_get_localization->{weekday}}
0  'Sunday'
1  'Monday'
2  'Tuesday'
3  'Wednesday'
4  'Thursday'
5  'Friday'
6  'Saturday'