A tutorial type puzzle which is fun to solve in a group. So everybody pair up, it's time for a 5 star puzzle!
Note: Contrary to what you might think at initial glance of the puzzle, and what you might think in subsequent steps, you do not need Linux to solve this puzzle. The puzzle is solvable in any operating system. Even KolibriOS, probably.
My friend Mentat often makes unique puzzles for me, and today was no exception. He, armed with a devious new idea, came on IRC and bothered me once more.
[Click on the image to enlarge]
Then, I received a DCC protocol request, as I expected. Three files named Mentat.? Mentat2.? and Mentat3.? were sent to me. After viewing the magic numbers of the three files, I determined 1st was data, and the 2nd and 3rd were PNGs, so I changed the extensions to Mentat2.png and Mentat3.png so they would open.
And finally, here's the incomplete file Mentat.?, reproduced in plain text. Two of the characters are not representable in ASCII, so you'll have to insert them via. a Hex Editor. Those two are represented below by <8F> and <16>, where those are the hex values you must need to insert in their place.
t~01!½lS06¡§Ç-´Ágn"‡¿v;=t—†Â<8F>ÿJ™«\ž×=G<16>u¾<ˆ¸Ï÷w
To solve this puzzle: just follow the instructions Mentat gives.
Do as the file(1) program does, and query the file with a search for the bytes of the magic number header you have.
With a fully complete file, you should be able to put the 8F and 16 in with a Hex Editor.
Using file(1) or just Googleing it should tell you the kind of file it is, and how to run it. Of course, it's an encrypted file with a password.
The password, like Mentat says, is encoded in the two images.
Good luck.