brandnewyou has asked for the wisdom of the Perl Monks concerning the following question:

One of my colleagues gave me some text to decode.

He says it was run through
'perl -pe 's/\W/\n/g' filename.ps | sort | uniq | fmt -65 | rot13'
on a unix machine.

Note the file was in postscript. I've consulted some of you monks on the chatterbox, however I'm still not clear whether the result of this operation can even be decoded.

Thanks for any help you can provide!!!

The output of the above command on the file is as follows: 

0 001 008 01 012O 018 02 027 028 03 044 048 049 05 053 059 06
066 07 073 075 076 077 079 08 084 087 088 1 10 100 100000 1005
101 102 104 105 106 107 11 110 112 118 12 120 122 123 124 128
129 13 130 132 133 136 138 14 142 143 144 148 15 150 151 152 154
155 16 160 162 164 166 167 17 172 174 175 176 178 18 180 181 183
184 185 186 19 190 191 192 193 194 195 196 197 198 2 200 2007
2007d1 202 203 204 207 208 209 20n90 21 210 214 214yr 214any
214arq 214efg 215 216 22 220 223 226 228 23 232 233 234 235 236
237 24 242 244 25 252 253 255 256 260 263 264 266 267 268 27 272
274 275 278 28 280 284 285 286 29 292 294 296 297 298 299 3 30
301 305 306 307 308 31 310 311 317 318 32 320 321 322 323 324
325 326 327 328 329 33 333 334 335 337 338 34 340 341 342 343
344 345 346 347 349 35 350 351 352 353 356 357 358 359 36 360
361 362 364 365 369 37 370 371 372 373 374 376 377 379 38 381
382 385 386 388 389 39 393 394 396 397 398 3P 3p 4 400 401 406
408 41 410 412 413 415 416 422 425 428 43 430 434 436 437 438 44
440 442 443 452 454 455 46 460 464 466 467 47 472 476 478 479 48
484 488 490 491 497 498 5 50 500 501 502 503 506 508 509 51 514
517 518 52 520 521 526 528 53 530 532 533 534 538 540 542 543
544 545 548 55 550 551 552 554 556 557 559 56 562 566 568 569
573 574 576 577 578 579 58 580 581 586 587 588 592 596 6 606 608
61 610 612 616 62 620 628 632 633 64 640 644 65 651 652 656 657
658 66 666 666666667 667 668 67 675 676 678 68 686 691 693 695
697 7 702 709 71 714 718 72 734 74 741 742 75 758 76 766 767 768
77 78 789 79 792 8 80 801 806 81 817 82 83 832 834 837 846 85
851 859 86 864 865 872 88 9 90 901 916 92 925 926 93 936 94 96
97 99 997 998 N NR NETI Nnphgr Npvephzsyrk Nqvrerfvf Nqbor
Ntenir Nafj Nevat Nfpraq Nffhzr Nffhzvat Ngvyqr O OC
OrtvaQrsnhygf OrtvaSrngher OrtvaCntrFrghc OrtvaCebybt
OrtvaErfbhepr OrtvaFrghc Obyq ObyqVgnyvp Oevna P PY PZCF PAG
Pprqvyyn Pt Px Pbqr Pbhevre Pe PerngvbaQngr Perngbe Q QN QP QR
QRSF QY Qngn Qrsnhyg Qraavf Qvfgnapr Qb QbphzragZrqvn
QbphzragArrqrqErfbheprf QbphzragFhccyvrqErfbheprf Qen R RORTVA
RRAQ RAP0 RBS RC Rnphgr Rpvephzsyrk Rqvrerfvf Rtenir Rapbqvat
RaqPbzzragf RaqQrsnhygf RaqSrngher RaqCntrFrghc RaqCebybt
RaqErfbhepr RaqFrghc Rgu Rheb Rknz S S0 S1 S2 S3 S4 S5 S6 S7 S8
S9 SVQ SVYR SY Snhyg St Svyy Svany Sx Sbag SbagOObk SbagZngevk
SbagAnzr Se T TAHznxrsvyr Tv U Uryirgvpn Uvf Ub V Vnphgr
Vpvephzsyrk Vq Vqvrerfvf Vs Vtenir VzntvatOObk Va
VapyhqrErfbhepr Vafregvba Vgnyvp Vgf W Wn X Y YF YJ Ybtva Yfynfu
Z ZNAHNY ZS ZG ZnxrGenafsbezrqSbag Znxrsvyr Zne Zhygvpf Zhygvcyr
A AHYY Anzr Arngarff Ab Agvyqr B BR BAY BF Bnphgr Bpvephzsyrk
Bqvrerfvf Btenir Ba Bcra Bevragngvba Bfynfu Bgvyqr C CORTVA CRAQ
CY CYT CEVAG CF Cntr CntrZrqvn CntrBeqre CntrFvmr Cntrf Crey
Cyrnfr Cbegenvg CebpFrg Chfuvat D E EP ER ERF EY Er Erfbhepr
Erghea Evgpuvr Ebzna F FP FS FA FG FGQVA Fpnaare Fpneba
Frtzragngvba Fcnep Fcrrq Fdhrrmrq Fgevat Fgehpghe Flzoby G GZ
GEHR Gur Gubzcfba Gubea Guh Gvzrf Gb Genvyre H Hnphgr
Hpvephzsyrk Hqvrerfvf Htenir HavdhrVQ Havk Hfr Hfvat I IZF J
Jung Jura Juvpu K L Lnphgr Lqvrerfvf Lv M MncsQvatongf Mpneba n
nPp nPc nW nF nnphgr noyr nobhg np npprff npvephzsyrk npgbe
nphgr nqq nqvrerfvf nqwhfgvat nr ntenir nytbevguz nyy nyyf nybnq
nyenql nyhr nzcrefnaq na naq nabgure nafj nafjre nafjref nag
nagrq nc ncceb nccebcev nccebcevngr nccebkvzngr ne nep nepa ner
nevnoyrf nevat neenl nf nfpvvpvephz nfpvvgvyqr nfubj nffvtazragf
nffbpv nffbpvngrq nfgrevfx nfgber ng ngr ngrq ngvyqr nhkyvo ni
njvqgufubj o onpxfynfu onynaprq one or ortva oryy orexryrl ovt
ovanel ovaq obbxf oenpryrsg oenprevtug oenpxrgyrsg oenpxrgevtug
oerir oebxraone ohyyrg ol p pnyphyngbe pnyyvat pnz pna pnaabg
pneba pnfr pp pprqvyyn prqvyyn prag punvava punvavat pune pubvpr
pvq pvrf pvephzsyrk py pynff pyrna pyrne pyvccngu pybfr
pybfrcngu pz pzcf012o pbqr pbyyvfvba pbyba pbyhza pbz pbzzn
pbzznaq pbzcnerGb pbzcvyrq pbzcyrgr pbzchgr pba pbapngzngevk
pbagnva pbagragf pbc pbcl pbclevtug pbeerpg pbhagqvpgfgnpx
pbhagf perngr perngrq pf pheerapl pheeragqvpg pheeragzngevk
pheeragcnpxvat pik q q730 q731 q7oq3q qnttre qnttreqoy qngn qok
qr qrnqorrs qrpynengvbaf qrpyner qrs qrsvarsbag qrterr qrcraqra
qrcf qrcgu qrfvtarq qvpg qvrerfvf qverpgbel qvi qvivqr qbyyne
qba qbgnpprag qbgyrffv qbgyrffw qbhoyr qhc qhcyvpngr r rnpu
rnphgr rns rnepurf rnfl rpvephzsyrk rq rqvrerfvf rqh rrpf rs
rtenir rvtug ryrzrag ryrzragf ryfrjurer ryl rz rznvy rzqnfu
rzcbenel ra raq raqnfu ragre rb rdhny rdhnyf re reavtuna reebe
rel rf rgu rknz3 rkpu rkpynz rkpynzqbja rl rlobneq s snyfr srpg
ss ssors530 ssv ssy strgf sv svo svyranzr svyy svaq svaqsbag
svir sy sybeva sbyyb sbag sbb sbe sbenyy sbez sbezhyn sbhaq sbhe
senpgvba serr sebz shap shapgvba shapgvbaf sl t tn tr trarevp
treznaqoyf trg tv tenz tenir terngre terfgber tebss tebcf tfnir
thvyyrzbgyrsg thvyyrzbgevtug thvyfvatyyrsg thvyfvatyevtug thzrag
u unfu unfuPbqr unfuvat unfugnoyr ung ur urnq urnqref urnc urer
uvpu ub ubar uggc uhatnehzynhg uj ulcura v vnphgr vp vpvephzsyrk
vpgher vqvrerfvf vs vsryfr vtenir vv vvv vzcyrzragrq vzcbeg va
vapyhqr vaqrk vaqvpngrf vat vaare vachg vafregvba vag vagre vagb
vb vf vg vgrz vgrzf vgu vgenafsbez vk w wne wnin wninp wqo x xrl
xabja y ynof ynat ynfg yq yr yrsg yrff yrggre yrggref yriry0
yriry1 yvx yvar yvarne yvarf yvargb yvax yvag yvfg yb ybnq
ybnqvat ybony ybt ybtvpnyabg ybbc yfynfu z znpeba znva znx znxr
znxrsbag znxvat znyybp zna znaq znavchyngvba znahnysrrq zngevk
znk znkyratgu znl zre zrffntr zvtug zvahf zvffvat zvg zz zb
zbqhyr zbfg zbirgb zh zhpu zhy zhygvcyr zhygvcyl zl a anx anzr
anc aq ar arrqrq art arjcngu avar avmrq abqr abqr_ers abg abgqrs
ag agrearg agvyqr agvba ahyy ahzore ahzoref ahzorefvta ahzrenyf
b bnphgr bognvarq bp bpvephzsyrk bqvrerfvf br bs btbarx btenir
bv bvagre bvagf bynevf byq bzcnevfbaf bzcvyre bzchgrq bzchgre ba
bar barunys bardhnegre barfhcrevbe bayl bagb bc bcrengvat be
beqre beqsrzvavar beqznfphyvar bex begu bfynfu bfg bg bgrf bgure
bgvyqr bh bhyq bhg bhgchg c cntr cntrf cnentencu cnerayrsg
cneraevtug cneg cnffrq cnguoobk crarq cre creprag cresrpgyl
cresbez crevbq crevbqpragrerq cregubhfnaq cvcrq cyhf cyhfzvahf
cbvag cbvagrq cbvagre cbvagref cbvagf cbc ccrne cevngr cevag
cevagrq cevags cevagsvyr cevagyvfg ceb ceboyrzf cebpfrg cebqhprq
cebtenz cebcreyl chg d dhrfgvba dhrfgvbaqbja dhvpx dhbgrqoy
dhbgrqoyonfr dhbgrqoyyrsg dhbgrqoyevtug dhbgryrsg dhbgrevtug
dhbgrfvatyonfr dhbgrfvatyr e epheirgb er ernfba ernfbanoyr
erphefv ertvfgrerq ercrng erfbyh erfbyhgvba erfgber erghea
erghearq ergheaf evtug evat evfx evgr eyvargb ezbirgb ebtenz
ebyy ebat ebbg ebgngr ebhaq efr efvat eg f fn fnir fp fpnyr
fpneba fpengp frnepu frpgvba fryrpgvba frzvpbyba frgpzlxpbybe
frgqnfu frgsbag frgtenl frgyvarpnc frgyvarwbva frgyvarjvqgu
frgzngevk frgzvgreyvzvg frgbirecevag frgcnpxvat frgcntrqrivpr
frgetopbybe frgfgebxrnqwhfg frira furyy fub fubhyq fubj fubjcntr
fvatyr fvk fynfu fznyyre fbeg fcnpr fcnprf fg fgnpx fgnaqneq
fgneg fgngrzrag fgngrzragf fgnghfqvpg fgqva fgqvb fgreyvat fgber
fge fgepzc fgeqhc fgevpg fgevat fgevatf fgebxr fgehpg fgehpgherf
fho fhpprff fhz flfgrz g gnoyr gny gne go guna gung gur gurer
gubea guerr guerrdhnegref guerrfhcrevbe gv gvyqr gvba gzc gb
gbgny genqrznex genafsbez genafyngr gerr gerr_ers gevat gehr gf
gher gj gjb gjbfhcrevbe glcrqrs h hnphgr hooyr hpvephzsyrk hpfp
hqvrerfvf htenir hx hzore hapbaqvgvbany hapgvba haqrefpber hfr
hfrq hfreqvpg hfvat hfhnyyl hg hgvy i in inyhr ir irefvba iv
ivqrq ivv ivvv ibvq j jnagxrl jnc jr jro jre jung jurer juvpu jv
jvqgufubj jvyy jvat jvgu jyl jz ja jevgr jevgvat jebat jf jjj k
kvfgvat kvg kcrpgrq kcerffvba kcerffvbaf kg l ln lnphgr lp
lqvrerfvf lra lt lv lvryq ly lbh lbhe m mpneba mreb

[download]

Replies are listed 'Best First'.
Re: can this text be recovered???
by kyle (Abbot) on Mar 19, 2007 at 17:51 UTC

    Let me start by spelling out the steps this text went through.

    1. Every non-word character (characters other than letters, digits, and the underscore) was replaced with a newline. That will be hard to reverse because those characters are, for all intents and purposes, deleted.
    2. The resulting lines were sorted. Again, this is hard to reverse because you can't recover the original order.
    3. Duplicate lines in the sorted output were discarded. Again, you can't tell how many copies of a particular line there were.
    4. The text was reformatted (word wrapped). You can't reverse this either.
    5. It was rot13 encoded. This is easily reversed.

    I think it's pretty clear that the original text can not be recovered.

[reply]
      1. The text was reformatted (word wrapped). You can't reverse this either.

      That step can be reversed I think, because you know from what was done before that every word stood on one line.

      Not that it would help for the original problem.

[reply]
Re: can this text be recovered???
by Skeeve (Parson) on Mar 19, 2007 at 17:56 UTC

    It can't.

    perl -pe 's/\W/\n/g'

    This already removes essential PostScript characters like +, * ( ) ...

    sort

    this destroies the sequence

    uniq

    This will remove any duplictes so removes some more information

    fmt -65 | rot13

    fmt doesn't destroy anything more, neither does rot13.

    Simply pyping the text through ro13 should reveal all the unique words from the original text but you will never be able to reconstruct the original without additional information.

    s$$([},&%#}/&/]+}%&{})*;#$&&s&&$^X.($'^"%]=\&(|?*{%
    +.+=%;.#_}\&"^"-+%*).}%:##%}={~=~:.")&e&&s""`$''`"e
[reply]
[d/l]
[select]
Re: can this text be recovered???
by eric256 (Parson) on Mar 19, 2007 at 17:45 UTC

    Wouldn't the sort and uniq remove too much data? like the order?


    ___________
    Eric Hodges
[reply]
Re: can this text be recovered???
by Preceptor (Deacon) on Mar 20, 2007 at 12:47 UTC
    rot13 is entirely reversible.

    fmt isn't explicitly reversible, but it it doesn't necessarily hurt the 'meaning' - a textfile that's been formatted is still going to be readable. However what it's effectively doing is 'removing' your line boundaries, which are field delimiters used in 'sort' and 'uniq'

    sort is removing information - the word order.

    uniq is also removing information - the number of occurances of each word.

    Oh, and the perl regexp is also removing information from your source data, which given it starts as postscript may be a problem.

    Outside very trivial cases, a 'sort | uniq' will effectively destroy the meaning of the information contained in a file, and is effectively irreversible.

    This doesn't necessarily mean all is lost, however you'll be reduced to jigsaw puzzle 'reconstruction' rather than any form of automatic process.

    Start by reversing the rot13. That's trivial - just rot13 it again

    Then you' get to try and figure out where the line breaks were. This _should_ be doable, because your text is sorted alphabetically - the 'start' of the next line will be alphabetically 'after' the start of the current line, and only 'just'.

    Reversing the sort is going to be a guessing game I'm afraid. As is reversing the uniq. Because they both work on a full line at a time, it may be possible to do this, but I don't think postscript has any form of sequencing

    Reversing the 'formatting strip', might again, be doable, but will require you to have a look at the postscript format. I seem to recall that postscript only tends to use '%'s and '/'s, which again, you may be able to reconstruct by guesswork, and by counting whitespace - cleartext is unlikely to have a triple space, so it might well be a good indicator that it was replacing ' / ' for example.

    All the above is liable to be fairly time consuming, and there's no guarantee of success. A partial result (e.g. restore original content, rather than formatting) may be achieveable, but that depends an awful lot on what the source data were.

    Of course, you could always go for plan B, and go hunting for 'filename.ps' in your collegue's home directory/elsewhere on the network.

[reply]
Re: can this text be recovered???
by brandnewyou (Initiate) on Mar 19, 2007 at 19:15 UTC
    What are the lines of numbers at the top the result of? I suppose they surfaced to the top after the sort command was performed, but I'm not sure about this.

    From the comments already posted I understand that the document probably couldn't be decoded in its entirety. But if there are ways to recover some of the text, this would almost be just as useful!

    Thanks!

[reply]

      You can get the words by running it through rot13. 

      perl -pe 'tr/a-z/n-za-m/' < encoded

      [download]

      That will be every unique word that was in the original text, in alphabetical order.

[reply]
[d/l]

        And to rot13 the uppercase characters: 

        perl -pe 'tr/a-zA-Z/n-za-mN-ZA-M/' < encoded

        [download]

[reply]
[d/l]

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