# referred to as 'words2date.pl' below
use strict;
use warnings;
use POSIX qw/strftime/;

my $datewords = join q{ }, @ARGV;

# Take "vague" words and convert them into a
# date/time stamp, e.g.,: "now", "today", "5pm Friday"

sub format_epoch {
  my $epoch = shift;
  # example, Tuesday, December 12, 1995
  return strftime(qq{%A, %B %d, %Y},localtime($epoch));
}

my $static_phrases = {
  now       => sub { print format_epoch(time) },
  today     => sub { print format_epoch(time) },
  tomorrow  => sub { print format_epoch(time + 86400) },
  yesterday => sub { print format_epoch(time - 86400) },
};

if ( defined $static_phrases->{$datewords} ) {
  $static_phrases->{$datewords}->();
}
else {
  warn qq{[WARNING] I do not understand what you mean by, "$datewords"\n};
}

##</code><code>##

SELECT DATE_ADD('2008-01-02', INTERVAL 31 DAY)