Friday Fun: A Riddle

by Erica Sadun

What do all the following dates have in common?

16 Nov 2006, 31 Oct 2006, 29 Sep 2006, 21 Sep 2006, 12 Sep 2006, 17 Aug 2006, 09 Aug 2006, 01 Aug 2006, 29 June 2006, 27 June 2006, 23 May 2006, 11 May 2006, 17 Apr 2006, 03 Apr 2006, 13 Mar 2006, 01 Mar 2006, 14 Feb 2006, 10 Jan 2006, 3 Jan 2006

Answer after the jump.


Cameron Hayne
2006-11-17 20:21:41
This is the sort of riddle that Google is good at solving:,+31+Oct+2006,+29+Sep+2006,+21+Sep+2006,+12+Sep+2006,+17+Aug+2006,+09+Aug+2006,+01+Aug+2006,+29+June+2006,+27+June+2006,+23+May+2006,+11+May+2006,+17+Apr+2006,+03+Apr+2006,+13+Mar+2006,+01+Mar+2006,+14+Feb+2006,+10+Jan+2006,+3+Jan+2006&btnI="I'm Feeling Lucky
2006-11-19 20:04:13
Terminal to the rescue!

You can un-rot13 by typing in the following:

echo "Gurl ner nyy qngrf ba juvpu Nccyr eryrnfrq Frphevg Hcqngrf guvf lrne." | tr "[n-za-mN-ZA-M]" "[a-mn-zA-MN-Z]"

The "tr" command allows you to "transpose" characters. In this case, it is matching each character to the thirteenth previous charactor Normally, it is used to convert upper to lower case, etc:

echo "$string" | tr "[a-z]" [A-Z]" #Convert to uppercase
echo "$string" | tr "[A-Z]" "[a-z]" #Convert to lowercase

You can also use it to ROT-13 text for you:

echo "$text" | tr "[a-mn-zA-MM-Z]" "[n-za-mN-ZA-M]"

For more information about the "tr" command type the following command:

$ man tr

That will display the "manpage" on the tr command.

Adriano Ferreira
2006-11-20 05:37:11

Drive to the the nearest CPAN and install Crypt::Rot13 (I had to say "install AYRNIEU/Crypt-Rot13-0.6.tar.gz" in CPAN shell).

Then just do

$ perl -MCrypt::Rot13 -e '
$rot13 = Crypt::Rot13->new;
print $rot13->rot13' 'Gurl ner nyy qngrf ba juvpu Nccyr eryrnfrq Frphevgl Hcqngr f guvf lrne.'