[Discuss] Please help with a BASH puzzle

[Chris Tyler]

This will generate a "complete" file (36^4 = 1.6 million lines, 8.1 MB) in
bash:

   a="{$(echo {0..9} {A..Z}|tr " " ,)}"; eval echo $a$a$a$a | tr " " "\012"
>/tmp/all

...Which you can then compare your input file against using the comm
command. (It runs in <5s on my chromebook here).

-Chris


On Fri, Aug 23, 2019 at 9:12 PM David Kramer <david at thekramers.net> wrote:

> I should mention I learned this technique from
>
> https://www.cyberciti.biz/faq/explain-brace-expansion-in-cp-mv-bash-shell-commands/
>
> On 8/23/19 9:11 PM, David Kramer wrote:
> > rIs it base 36 then?
> >
> > One way to build the list of expected values is bash brace expansion,
> > where {a,b,c}{1,2,2} will output all combinations of those sets.
> > Here's an example going from 1 to 4 in 4 digits, but you can see how
> > you would do this with 0-9 then A-Z in each of the 4 sets:
> >
> > $ echo {1,2,3,4}{1,2,3,4}{1,2,3,4}{1,2,3,4}
> > 1111 1112 1113 1114 1121 1122 1123 1124 1131 1132 1133 1134 1141 1142
> > 1143 1144 1211 1212 1213 1214 1221 1222 1223 1224 1231 1232 1233 1234
> > 1241 1242 1243 1244 1311 1312 1313 1314 1321 1322 1323 1324 1331 1332
> > 1333 1334 1341 1342 1343 1344 1411 1412 1413 1414 1421 1422 1423 1424
> > 1431 1432 1433 1434 1441 1442 1443 1444 2111 2112 2113 2114 2121 2122
> > 2123 2124 2131 2132 2133 2134 2141 2142 2143 2144 2211 2212 2213 2214
> > 2221 2222 2223 2224 2231 2232 2233 2234 2241 2242 2243 2244 2311 2312
> > 2313 2314 2321 2322 2323 2324 2331 2332 2333 2334 2341 2342 2343 2344
> > 2411 2412 2413 2414 2421 2422 2423 2424 2431 2432 2433 2434 2441 2442
> > 2443 2444 3111 3112 3113 3114 3121 3122 3123 3124 3131 3132 3133 3134
> > 3141 3142 3143 3144 3211 3212 3213 3214 3221 3222 3223 3224 3231 3232
> > 3233 3234 3241 3242 3243 3244 3311 3312 3313 3314 3321 3322 3323 3324
> > 3331 3332 3333 3334 3341 3342 3343 3344 3411 3412 3413 3414 3421 3422
> > 3423 3424 3431 3432 3433 3434 3441 3442 3443 3444 4111 4112 4113 4114
> > 4121 4122 4123 4124 4131 4132 4133 4134 4141 4142 4143 4144 4211 4212
> > 4213 4214 4221 4222 4223 4224 4231 4232 4233 4234 4241 4242 4243 4244
> > 4311 4312 4313 4314 4321 4322 4323 4324 4331 4332 4333 4334 4341 4342
> > 4343 4344 4411 4412 4413 4414 4421 4422 4423 4424 4431 4432 4433 4434
> > 4441 4442 4443 4444
> >
> > I do like Rich's idea of creating the ideal file once, possibly using
> > this technique or really in any programming language, and just doing a
> > diff.  If you don't want to do that, though, you could use this
> > technique in an outer for loop, and for each one, read a line from the
> > file under test, and if the line doesn't match the expected value,
> > report the error and loop until you see the next match.
> >
> > On 8/23/19 7:17 PM, Bill Horne wrote:
> >> David,
> >>
> >> Thank you for your suggestion, but they are not only number, but
> >> alpha values too.
> >>
> >> Sorry, though: I chose poor examples.  The file can contain any digit
> >> 0-9, and any alpha A-Z. There are no punctuation marks and no white
> >> space.
> >>
> >> Sorted values range from 0000 to ZZZZ.
> >>
> >> HTH.
> >>
> >> Bill
> >>
> >>
> >> On 8/23/2019 6:51 PM, David Kramer wrote:
> >>> Are these hex numbers?  bc can convert hex to decimal and do hex
> >>> math.  The hard part is calculating the next value, and here's an
> >>> example of doing that.
> >>>
> >>> nextValue=`echo "obase=16; ibase=16; ${lastValue} + 1" | bc`
> >>>
> >>> Then all you need to do is compare whether the next line you read is
> >>> equal to nextValue.
> >>>
> >>>
> >>> On 8/23/19 6:32 PM, Bill Horne wrote:
> >>>> Thanks for reading this: I appreciate your time.
> >>>>
> >>>> I'm trying to do something that should be very easy to do, and yet
> >>>> I can't remember how to do it, and I'm asking for help.
> >>>>
> >>>> I have an alpha-numeric, sorted file, that looks like this:
> >>>>
> >>>> 01AA
> >>>>
> >>>> 01AB
> >>>>
> >>>> 01AC
> >>>>
> >>>> 01AE
> >>>>
> >>>> 01AF
> >>>>
> >>>> .. etc.
> >>>>
> >>>> I'm trying to remember what BASH utility, script, or command would
> >>>> flag the missing value (in this case, "01AD"). There are, of
> >>>> course, any number of ways to program a solution, but I can't
> >>>> remember which of the BASH utilities will do it. All suggestion
> >>>> welcome, and thanks in advance.
> >>>>
> >>>> Bill Horne
> >>>>
> >>>> _______________________________________________
> >>>> Discuss mailing list
> >>>> Discuss at blu.org
> >>>> http://lists.blu.org/mailman/listinfo/discuss
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