Decoding the obfuscated bash script on a Uniqlo t-shirt

517

sspeerer about 4 hours ago 102 commentsRead Article on tris.sherliker.net

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Discussion (102 Comments)Read Original on HackerNews

estebarb•about 1 hour ago

"Uniqlo x Akamai sells another design of shirt in the same range which is plainly incomplete"

Imagine having to return a t-shirt because that malfunction!

— I don't understand why are you returning this, was the size wrong or you didn't like it?

— No, there is a syntax error at line 37 that makes it impossible to run, and I'm concerned people on the street may think I promote unsafe bash scripting.

cromka•about 1 hour ago

Oh the Karens these days!

wbh1•about 2 hours ago

I love this shirt! Here's a nice video from the actual designer about the process of making this shirt (including intentionally making it hard to OCR): https://youtu.be/jocGLiecpjU?t=526

speerer•about 2 hours ago

Author here. Thank you so much for the link which I hadn't seen! I'm very happy to see this and I'm gratified that it was deliberately difficult to OCR, not just me.

raffael_de•3 minutes ago

while base64 can be considered obfuscation in this context and its inverse as decoding I can't help but feel this title is overselling and catering to a rather cyber-cheesy marketing campaign at that.

Tiberium•about 4 hours ago

OCRing this is a nightmare and is a good benchmark to any self-proclaimed good OCR/vision model.

I think though it could likely be easily OCR'd if you give the image to any decent agentic harness with a good vision model, e.g. newest Claude/GPT ones, and tell them to split the image per lines, and then just OCR each line individually.

I wonder if the script itself was written by an LLM before obfuscation? There seem to be a lot of comments in it, but in this case it's still ok :)

lemagedurage•about 3 hours ago

I don't think it was written by an LLM, some things stand out:

The congratulations text is both in English and Japanese. Contains a single heart emoji.

There was an intention to have a cyan to orange gradient, but the range starts in an ANSI block, ends halfway through the 256 color block and 256 terminal colors are not arranged like a gradient at all.

There's no sleep at the end of the loop where I feel like an LLM would add that defensively.

n2j3•about 2 hours ago

Human here. I added a sleep 0.5 at the end, it's too fast to read otherwise. Makes for a nice terminal screensaver!

INTPenis•about 2 hours ago

Hi fellow human, I got the same idea. Just a sleep 0.1 before the echo "" makes it readable. Otherwise it scrolls way too fast.

make3•about 2 hours ago

"the code is not quite detail oriented enough to be AI", times are changing

DaSHacka•about 2 hours ago

More like 'not boilerplate-y enough'

lemagedurage•about 2 hours ago

Ehh, AI makes plenty mistakes but they have a different vibe to it.

In my mind an AI would do something the most popular way even when that's not appropriate.

A human might do things in an unpopular way even when that's not appropriate.

OtherShrezzing•about 2 hours ago

Safari's copy-text-from-image feature manages the entire base64 part of the string, except for the first character (I instead of a T). Weirdly, it gets much worse performance if you try to copy the entire string, including the hashbang part.

I wonder what it's doing under the hood to get such good performance?

khurs•about 2 hours ago

Didn't know Safari had this.

Looked it up, you put mouse over text, then just select and copy it - very cool!

https://support.apple.com/en-gb/guide/safari/ibrw20183ad7/ma...

al_borland•5 minutes ago

It’s actually a system feature, not strictly a Safari feature. It also works in Photos, Preview, etc.

On meetings I will often take a screenshot of the URL someone is presenting. I’m then able to just open the image and click the URL in the image.

iamflimflam1•about 2 hours ago

There’s a whole bunch of hidden features that no one seems to be aware of.

Preview has pretty good background removal.

Notes will transcribe audio from audio files.

agys•about 2 hours ago

Preview has it too… And it works extremely well.

underyx•about 1 hour ago

I gave the photo to Opus 4.8 and it reconstructed the same script in one shot. Although it did say it had to correct some parts of it based on context where it suspected OCR mistakes.

shakna•about 2 hours ago

> I wonder if the script itself was written by an LLM before obfuscation?

From the prototype shown here [0], and the way they talk about their process, I sincerely doubt it. Especially as they mention trying to make it hard for AI to handle the output.

[0] https://youtu.be/jocGLiecpjU?t=567

cb321•about 1 hour ago

I watched that whole video link - thank you for that - and he doesn't really say. In fact, he spends much more time on the beige color harkening to computer case plastics of the 80s & 90s.

What made me wonder, personally, was that the output seems identical if you use "♥PEACE♥FOR♥ALL" instead of the version with internal repeats. IF there is any point to that "manual expansion of the cycles", IMO that deserves a comment much more so than "# Calculate length of text; text_length=".

Also, that `echo -n ...` followed by `echo ""` instead of just plain `echo` in the first place seems like the kind of copy-pasta code LLMs generate. Then again, regular devs also write pretty bad copy-pasta code.

There is also this the weirdly "broken down" calculation with 3 `bc` invocations not 1 as if it was translated from a language with more arithmetic/special function power than bash.

There is also the color scale stuff done in the loop instead of outside (except the one color=$(..)) which seems very unnatural and also very like machine translation.

Also, at least for me, on my bash-5.3.15(1), `char="${text:t % text_length:1}"` does not work to slice out the multi-byte UTF8 heart symbols, but it sure does look like the kind of thing an LLM would do translating from a python3 script (such as something like https://news.ycombinator.com/item?id=48830669) into bash.

Another thing is, as others here have observed, there is nothing "gradual" about the xterm-256 color cube. So, "gradient" is a misnomer and exactly the kind of weird things LLMs do when they cobble text together.

Finally, all the tput stuff the script does instead of just "print x spaces" really smells like a human description of the side scroll in the video game graphic he shows inspired him somehow LLM-corrupted/complexified into the vertical scroll terminals do, but with a lot of extraneous complexity.

None of this is conclusive, but the video mentions 2023..2025 as when he did it and given that he was a designer and his concerns more visual than code-oriented, I'd have to say I disagree with your sincere doubt and I do strongly suspect the decoded script was very likely LLM-circa2024-generated, possibly with light post-edits.

The AI not handling the output relates to the final base64 output on the T-shirt (which other comments in this thread mention manually keying in or TFA discusses in the context of OCR). So, that is just not relevant to the question.

netsharc•about 2 hours ago

The last time Internet people were obsessed with OCRing some base64 was a few months ago when the DoJ released tons of emails from some guy who died, but they were released as rasterized PDFs.

Can't remember his name now, there's been so many distractions...

da_grift_shift•30 minutes ago

>I wonder if the script itself was written by an LLM before obfuscation?

I seem to recall seeing an Akamai-branded base64'd shell script on a white shirt pre-2021(?), so unless they've changed the code since then, I doubt it...

IshKebab•about 3 hours ago

Definitely LLM. No humans write that many comments.

ivolimmen•5 minutes ago

Since LLM's are mimicking our code my guess we do...

ChrisMarshallNY•about 3 hours ago

Ahem...

My code usually clocs at 50/50 (or thereabouts)[0]. Has, since my very first real engineering project (in 1987)[1]. I discuss in detail, here[2].

But one reason that I like LLMs, is that they help me to write even more documentation. I have found that I can instruct an LLM to revise my documentation, and make it even more effective.

[0] https://github.com/ChrisMarshallNY (My GH profile. Pretty much everything there, is like that -has, since long before LLMs were a broken rubber on the drug store shelf).

[1] https://littlegreenviper.com/wp-content/uploads/2022/07/TF30... (Downloads a PDF)

[2] https://littlegreenviper.com/leaving-a-legacy/

petu•about 3 hours ago

Human could write that many comments to get enough base64 text for a design. Maybe to even get some of the highlighted characters in places they want (roughly equally spaced apart).

latexr•about 3 hours ago

> No humans write that many comments.

Especially in a case like this, I would definitely write a lot of comments to aid in understanding, thus increasing trust so people would try it out and tinker with it.

boomboomsubban•about 2 hours ago

Plus the main point of this code is to have people look at it, the function is secondary to being an easter egg.

Tiberium•about 3 hours ago

Honestly it's a bit of a shame. I checked and they could've shortened their base64 payload by 304 chars by removing all comments except the top two congratulatory ones, or by 524 if they removed those too.

OtherShrezzing•about 3 hours ago

Would they still get the highlighted "PEACE FOR ALL" text throughout the shortened string? It looks like the length, and presence of those characters, was an explicit design choice.

lemagedurage•about 2 hours ago

Maybe they added the comments to get a longer payload for the sake of the shirt's design.

The comments can be more cute/awe inspiring for people who aren't as familiar with bash but like solving puzzles as well.

yborg•about 2 hours ago

The HN optimizing T-shirt compiler is the next stage here :D

saidnooneever•about 3 hours ago

im just sad it didnt render a qr code leading to malware :'). the different ways ppl look at obfuscated codes and scripts hah

world2vec•about 3 hours ago

Oh wow I saw that tshirt at the store and said to my girlfriend "no way that script is functional, probably just for show". I should have persevered.

actionfromafar•about 2 hours ago

An easy miss. :-) Most of the time our thoughts are on autopilot, since we are not calm.

forinti•14 minutes ago

This reminds me of a T-shirt I once saw that read:

          perl -e '
     "$a="etbjxntqrdke";
  $a=~s/(.)/chr(ord($1)+1)/eg;
        print "$a\n;"'

It's cursing. Don't run it if it might offend you.

Upon seeing this, I decided to golf and came up with a shorter version:

  perl -e "print chr 1+ ord for split //,'etbjxntqrdke'"

librasteve•2 minutes ago

  raku -e 'say "etbjxntqrdke".comb.map({chr .ord + 1}).join'

chrysoprace•about 2 hours ago

My old colleague had one with a Go program[0] which I always thought was quite cool.

[0] https://github.com/GL-Kageyama/UNIQLO_Akamai_T-shirt_Code

mdgld•about 2 hours ago

I wasn’t sure if you meant a Go solver or Go the language. Would be fun if someone wrote a Go program in Go

psd1•about 1 hour ago

Or a pong clone in Racket.

ExoticPearTree•about 2 hours ago

I got one this year with the Go code. Never actually thought it is legit code, just some random stuff.

qiqitori•about 2 hours ago

I once wrote a tool that helps with finding mistakes in OCR'd fixed width text, https://blog.qiqitori.com/2023/03/ocring-hex-dumps-or-other-...

Basically it just clusters same characters and asks the human to find the problems, which is easy when you're looking at a series of pictures like ssssss5sss.

The UI is kinda least-effort. Should ask a modern AI agent to make it look nice and intuitive, sometime maybe.

haileys•about 3 hours ago

I thought it was funny that the author used a variety of OCR tools with mixed success before spending a lot of time manually fixing up the output from the best one, rather than just typing it in

christoph•about 3 hours ago

That was also my thought… but I grew up mashing rubber keys for hours copying “games” out of magazines and books! Then hours after fixing all the typos!

forinti•8 minutes ago

I spent hours typing 6502 assembly. It went a lot better when someone dictated: LDA, STA, BEQ, LDY, STY...

rtldg•about 3 hours ago

Took me almost 2 minutes for 4 lines (and I missed a character in one of them!). I would opt for OCR too, obviously so I'm prepared for the next bash t-shirt I'd come across...

OtherShrezzing•about 2 hours ago

I think this is a case where two people can successfully complete the task manually faster than one attempting to automate it. Get a ruler, read five centimetres of characters to your colleague, have them type it in as you go, then repeat that five centimetres back to you. Correct as you go. Format your string with the same line-breaks as the t-shirt, and remove them at the end, so you can be sure you've got the correct length on each row. Trial-and-error adjust the five-cm distance depending on your success rate as you go along

All in, you should have a non-corrupted string in 10-15 min.

acters•about 2 hours ago

I ran it through paddle paddle OCR and it flawlessly did it. Google's OCR through my phone's Google lens had also worked at getting a very good extraction but not 100% correct. Definitely would spend less time fixing it than hand copying.

IDK what the author was using but I feel like he could have shared how his OCR attempt went, but I am thinking he tried some naive OCR tools.

speerer•about 2 hours ago

Author here - that's a good idea actually, it shouldn't be too hard to compare the various attempts. The tools I used were whatever my Android built-in is (likely Google Gemini, but I can't tell whether this is something Samsung has replaced in OneUI); tesseract; tesseract with various tweaks and charsrt restrictions; Claude; and finally, manual fixes based on disagreements between all the previous.

grumbel•about 2 hours ago

Gemini3.5 Flash didn't have a problem OCR'ing and base64 decoding it, despite the OCR step having errors, it just fixed them in the base64 decoding step.

mayas_•about 3 hours ago

"just typing it" would be more error prone for the average human

duskdozer•about 3 hours ago

I'm guilty of this, but for me this kind of thing is optimizing over annoyance rather than time.

speerer•about 2 hours ago

(Author here) Yes I agree. It was a fun side-quest though. Reminds me of https://xkcd.com/1205/

khernandezrt•10 minutes ago

Ive been to 3 Uniqlos in my are and i havent been blessed with a bash shirt :(

cb321•about 1 hour ago

For anyone that cares, this is a slightly less stupid Python version:

    #!/usr/bin/env python3
    from os   import environ; E = environ.get
    from math import sin
    from time import sleep
    text = "♥PEACE♥FOR♥ALL" # The text to sine-scroll animate
    nText  = len(text)      # Number of utf8 chars
    freq   = 0.2            # Frequency scaling factor
    color0 = 12             # xt256 Color cube segment 12..<208
    color1 = 208; nColor = color1 - color0
    (w, h) = (int(E("COLUMNS", 80)), int(E("LINES", 24)))
    t = 0
    while True:
        x = (w/2) + (w/4)*sin(t*freq)           # x pos via sine value
        x = max(0, min(w - 1, int(x + 0.5)))    # bound to tty width
        color = color0 + ((nColor*t)//h)%nColor # cycle colors
        ch = text[t%nText]  # Get char & Use xterm-256 color escs
        print("%*s\033[38;5;%sm%s\033[m\n" % (x, "", color, ch))
        t += 1
        sleep(0.1)   # original used bc shell outs to rate-limit

As mentioned in https://news.ycombinator.com/item?id=48830326 , the heart symbols did not otherwise even work for my bash and some have commented on liking the screen saver.

teo_zero•17 minutes ago

I don't know... I prefer unobfuscated text that you can immediately grok. The other day I saw this on a T-shirt:

> May the m×s/t² be with you

chrisweekly•21 minutes ago

Great post! It's interesting, detailed but concise, and well-written. Also, I appreciate the "no cookies or tracking" and attractive, functional and performant site design.

DrewADesign•about 3 hours ago

> I guess Uniqlo is run through Windows though: one thing that struck me was the font, which I’m almost certain is Consolas,

Surely this would use whatever font the virtual terminal profile was set to? I don’t know of any method to choose a virtual terminal font from bash and don’t see any code that addresses it?

nisiddharth•about 3 hours ago

They're referring to the font on the T-shirt.

tym0•about 3 hours ago

Thank you for spelling it out for me because I thought I was looking at a completely hallucinated AI article...

speerer•12 minutes ago

Author here. All hallucinations are my own. Now you point it out, I see why the jump in context from the terminal back to the tshirt font would give the wrong impression.

alexpotato•28 minutes ago

Fascinating that we have base64 but not error correction for it!

_flux•about 1 hour ago

On one hand it's nice how it's clean and commented, but on the other hand some golfing could have made the encoded block a lot more reasonable to actually manually enter.

speerer•11 minutes ago

It might not have filled up the whole shirt then?

puttycat•about 1 hour ago

The comments just mean they used AI to do that in 3 seconds

brightball•about 1 hour ago

Nice!

Might have to do something like that for a verse on the next Carolina Code Conference shirt. Been trying to figure out a good way to pull in cybersecurity.

shim__•about 1 hour ago

Could have saved 50% with 'base64 -d | gzip -d'

speerer•11 minutes ago

Maybe useful for those XS sizes.

sixtyj•about 1 hour ago

> Interesting. I told my wife "that’s basically how people ship viruses’ and bought it.

It’s a movie plot.

preetham_rangu•about 2 hours ago

The real threat model here isn't the base64 payload, it's Uniqlo turning a T-shirt into a QR code that requires a human OCR pipeline to redeem.

willejs•about 1 hour ago

Looks like it has a few shellcheck issues, and no set -euo pipefail? ;)

high_byte•about 4 hours ago

what if it contained a zero day for tesseract and the script you thought you got is just a throwaway

dylanzhangdev•about 3 hours ago

Cool! I bought one a few months ago as soon as I spotted it at a Uniqlo store, and later ordered a larger size online—I really love wearing them. But it never occurred to me to look into the story behind them.

brazzy•about 2 hours ago

After being primed by the article, I read the author's name as "Shirtliker"...

speerer•8 minutes ago

That's a new one and oddly apt :)

FijiBY•about 2 hours ago

Nice investigation, thx

doppp•about 3 hours ago

Thanks for the post! Love Easter Eggs like these!

khurs•about 2 hours ago

Brilliant marketing when you can get people to pay to walk around advertising with your logo!!

kijin•about 2 hours ago

Well at least they're not instructing consumers to run curl | bash.

That's better than half the tech howtos out there.

INTPenis•about 2 hours ago

No, they're instructing their customers to run unknown base64 encoded code instead. :D

tantalor•about 1 hour ago

TIL Consolas is a Windows font

l337h4x0rz•about 3 hours ago

there's no newline between the shebang and the actual code

icevl•about 3 hours ago

Base64 without error correction turns the t-shirt itself into a lossy transport layer, so the OCR/transcription step becomes the actual challenge.

bryanrasmussen•about 4 hours ago

Why does the shirt have an obfuscated bash script on the back?

Tiberium•about 4 hours ago

Because it's by Akamai, the blog links to https://www.akamai.com/newsroom/press-release/uniqlo-adds-ne...

kay_o•about 4 hours ago

Uniqlo frequently does collaborations. This was one with a tech company

wbh1•about 3 hours ago

It's at least the second one that Akamai's done, although I like this newest one the most.

The old one was: https://www.uniqlo.com/us/en/products/E459561-000/00

pezezin•about 2 hours ago

I have both of them and wear them to work regularly xD

The guy who founded the new political party Team Mirai also wears it frequently: https://en.wikipedia.org/wiki/Takahiro_Anno

breppp•about 2 hours ago

Feels very reminiscent of the style of old DeCSS tshirts

https://www.wired.com/2000/08/court-to-address-decss-t-shirt...

lloydatkinson•about 3 hours ago

P ./cool.sh: line 31: bc: command not found ./cool.sh: line 34: bc: command not found ./cool.sh: line 37: bc: command not found E ./cool.sh: line 31: bc: command not found ./cool.sh: line 34: bc: command not found ./cool.sh: line 37: bc: command not found

Very wow. Shame they assumed everyone has "bc"...

em500•about 3 hours ago

Why would that be a shame? "bc" is a mandatory POSIX command, while /bin/bash isn't (/bin/sh is the standard).

greazy•about 3 hours ago

Which distro are you running? Perchance did you run the shell script in alpine Linux (docker)?

piacos_•about 2 hours ago

it doesn't seem to be installed on my endeavouros laptop

lloydatkinson•about 2 hours ago

Debian.

comradesmith•about 2 hours ago

You are fun.

lloydatkinson•about 2 hours ago

Are we really at the "redditor insult" type comments stage of HN now? There is nothing wrong with saying a piece of code is broken.

deciduously•about 1 hour ago

Broken seems a little hyperbolic, it has an implicit dependency on a standard POSIX tool.

koiueo•34 minutes ago

> I ran OCR in a few ways: First, using the built-in OCR of the circle-to-search feature on Android, which is often very good. Second, by using Tesseract with a few options and tweaks. And third by running it through Claude. After diffing the three to look for mismatches and getting Claude to output a table of locations for quick scanning, it became trivial but time-consuimg to tidy up the remainder

I bet 10$ I'd spend less time typing it from the t-shirt. And I wouldn't boil two kettles of water in the process.

But hey, AI makes you 10x more productive, I suppose

speerer•9 minutes ago

(Author here) for unrelated reasons my typing is very slow at the moment, so I was keen to automate. I see that people are getting different results from Claude than I did though.

freedomben•25 minutes ago

You may want to retract that bet: https://news.ycombinator.com/item?id=48830846

koiueo•19 minutes ago

Yeah, I read that later.

My bet is against manual OCR with various engines + finding mistakes later using an LLM.