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haas:fall2019:unix:eocehints [2018/05/03 17:02] (current)
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 +======EoCE hints======
  
 +=====0x0=====
 +
 +  * Take note of the stated assumptions.
 +  * How might you utilize those in coming up with a solution?
 +
 +=====0x1=====
 +
 +  * Trouble using **dd(1)**? Try this [[/​haas/​spring2018/​unix/​projects/​dd_tutorial|dd tutorial]] I wrote.
 +  * Remember that **parts** are __pieces__ of a **whole**
 +  * Don't read from AND write to the same file at the same time.
 +
 +=====0x2=====
 +
 +  * Problems with **seq(1)**?
 +
 +<cli>
 +lab46:~$ seq 1 10
 +1
 +2
 +3
 +4
 +5
 +6
 +7
 +8
 +9
 +10
 +</​cli>​
 +
 +  * How about by an offset?
 +
 +<cli>
 +lab46:~$ seq 1 2 10
 +1
 +3
 +5
 +7
 +9
 +</​cli>​
 +
 +  * How about backwards?
 +
 +<cli>
 +lab46:~$ seq 5 -1 0
 +5
 +4
 +3
 +2
 +1
 +0
 +</​cli>​
 +
 +  * How to use in a loop?
 +
 +<code bash>
 +for value in `seq 1 2 10`; do
 +</​code>​
 +
 +  * Or based on variables?
 +
 +<code bash>
 +for value in `seq ${start} ${step} ${stop}`; do
 +</​code>​
 +
 +  * What, you mean I could have totally done that back then and saved myself all the hassle I went through?
 +
 +<cli>
 +lab46:~$ # yes
 +</​cli>​
 +
 +  * Also, some usage examples:
 +
 +<cli>
 +lab46:~$ ./pwn1.sh 12 17 idbase with3 with7
 +   base 2 |   base 3 |   base 7 |   base 8 |   ​base10 |   ​base16 |
 +----------+----------+----------+----------+----------+----------+
 + ​00001100 |    110-3 |    15(7) |      014 |   ​12(10) |     0x0C |
 + ​00001101 |    111-3 |    16(7) |      015 |   ​13(10) |     0x0D |
 + ​00001110 |    112-3 |    20(7) |      016 |   ​14(10) |     0x0E |
 + ​00001111 |    120-3 |    21(7) |      017 |   ​15(10) |     0x0F |
 + ​00010000 |    121-3 |    22(7) |      020 |   ​16(10) |     0x10 |
 + ​00010001 |    122-3 |    23(7) |      021 |   ​17(10) |     0x11 |
 +</​cli>​
 +
 +<cli>
 +lab46:~$ ./pwn1.sh 12 17 idbase with3 with7 noheader
 + ​00001100 |    110-3 |    15(7) |      014 |   ​12(10) |     0x0C |
 + ​00001101 |    111-3 |    16(7) |      015 |   ​13(10) |     0x0D |
 + ​00001110 |    112-3 |    20(7) |      016 |   ​14(10) |     0x0E |
 + ​00001111 |    120-3 |    21(7) |      017 |   ​15(10) |     0x0F |
 + ​00010000 |    121-3 |    22(7) |      020 |   ​16(10) |     0x10 |
 + ​00010001 |    122-3 |    23(7) |      021 |   ​17(10) |     0x11 |
 +</​cli>​
 +
 +<cli>
 +lab46:~$ ./pwn1.sh 12 17 with3 with7 noheader
 +     1100 |      110 |       15 |       14 |       12 |        C |
 +     1101 |      111 |       16 |       15 |       13 |        D |
 +     1110 |      112 |       20 |       16 |       14 |        E |
 +     1111 |      120 |       21 |       17 |       15 |        F |
 +    10000 |      121 |       22 |       20 |       16 |       10 |
 +    10001 |      122 |       23 |       21 |       17 |       11 |
 +</​cli>​
 +
 +Also, it won't be the end of the world if you don't implement **signed**. I'm making that particular thing optional.
 +=====0x3=====
 +
 +  * **authorized_keys** might be something worth exploring
 +  * your home directory follows you to the pi's, just as it does to the pods
 +  * permissions on related files and directories are VERY important
 +
 +=====0x4=====
 +
 +  * look inside readable text files. Useful information can be had that way.
 +
 +=====0x5=====
 +
 +  * Some usage examples:
 +
 +<cli>
 +lab46:~$ ./​catweek.sh
 +14
 +lab46:~$ ./​catweek.sh fullname
 +week14
 +lab46:~$ ./​catweek.sh fullname lastweek
 +week13
 +lab46:~$ ./​catweek.sh nextweek
 +15
 +lab46:~$ ./​catweek.sh start=monday
 +13
 +lab46:~$ ./​catweek.sh start=monday nextweek fullname
 +week14
 +lab46:~$ ./​catweek.sh 20180402 fullname
 +break2
 +lab46:~$ ./​catweek.sh 20180402 fullname nobreaks
 +week11
 +</​cli>​
 +
 +=====0x6=====
 +Times so far (in seconds):
 +
 +  * 6653 seconds
 +  * 6974 seconds
 +  * 7029 seconds
 +  * 8099 seconds
 +  * 8550 seconds
 +  * 9029 seconds
 +  * 9157 seconds
 +  * 10660 seconds
 +  * 12506 seconds
 +  * 13205 seconds
 +  * 13512 seconds
 +  * 15744 seconds
 +
 +  * Average time is 2.803 hours.
 +
 +Be sure to plan accordingly.
haas/fall2019/unix/eocehints.txt · Last modified: 2018/05/03 17:02 (external edit)