use Time::Local;
use POSIX 'strftime';

# get today
my @today = localtime;

# normalise to midday
@today[0 .. 2] = (0, 0, 12);

# get normalised today
my $today = timelocal @today;

# get current day of week
my $dow = (localtime($today))[6];

# get last Sunday (day 0)
my $sunday = $today - (86_400 * $dow);

# get Tuesday (day 2)
my $tuesday = $sunday + (86_400 * 2);

# print Tuesday in a nice format
print strftime "Tuesday is %d %B %Y\n", localtime $tuesday;