The builtin function localtime gives you all the elements you need.

my ($sec,$min,$hour,$mday,$mon,$year,$wday,$yday,$isdst) =
    localtime(time);
my $monday = $mday - $wday + 1;
my $friday = $mday - $wday + 5;
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Of course this doesn't work if you aren't in the middle of a month (e.g. if ($mday - $wday + 1) < 0). You could take your time() and add or subtract 24*60*60 seconds per day to get the right unix time, then convert to date with localtime()