[Discuss] Please help with a BASH puzzle

David Kramer david at thekramers.net
Fri Aug 23 21:12:02 EDT 2019


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
>>>>
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