[SOLVED] Shell Script - Coded Alphabet

astrogeek · 12-11-2019, 12:52 PM

"Didn't work" is not a useful description of what you have tried and what the results were. Posting whole cloth code repeatedly also tends to cause others to look elsewhere.

Have you actually read and tried to understand how that code is working? Look at the last line for one big clue as to why it may not be decoding that string.

I see also that you have changed the name of the crypt array from the original script, reversed the keys and values, which makes no sense with your subsequent exchange of keys and values using the same array (and won't work either!). Think about how that was working in the first test used with the encode function, then think about what it must do to allow you to reverse the process with the decode function... learn!

Pinguino99 · 12-11-2019, 01:41 PM

it's only been 2 weeks since i'm learning shell script
it's my first programming language
forgive my ignorance

just wanted to make it work

pan64 · 12-11-2019, 02:01 PM

if you have just started you need to try something easier, take a simpler task.
If someone posts the solution you will not understand a line. What is your goal?
Or is this your homework?

Pinguino99 · 12-11-2019, 02:40 PM

I'm learning on my own through books
I like solving ciphers and I thought something like this to decipher
I didn't find any google search on how I could do this
I'm trying to understand the code, I know it has the array, the "for" is loop and "while" too,
I really wanted to be able to solve this

astrogeek · 12-11-2019, 03:35 PM

It is OK, no one is criticizing you, we want you to learn it!

Please read my previous post and consider the two main points I made:

* If you are trying to decode, should you change the function being called?
* If the script reverses the crypt array for use in the decode function, why would you rewrite it in reverse yourself?

The main point is this: If you want to understand how it works, you need to read it line by line and try to understand what exactly each line is doing for you. Don't make any changes to the code until you can explain why they are needed and what the change will do for you.

Making changes on top of changes which you do not understand leads nowhere.

Pinguino99 · 12-11-2019, 04:04 PM

Code:

#!/usr/bin/env bash

declare -A decrypt=(
    [AAAAAAAA]="A"
    [BBBBBBBB]="B"
)

decode () {
    local word=$1
    for ((i=0; i<${#word}; ++i)) ; do
        local char=${word:$i:8}
        printf %s'' ${decrypt[$char]}
    done
    printf '\n'
}

decode 'AAAAAAAABBBBBBBB'

I did it!
I did it!
I did it!
Hurray! Hurray! Hurray!

I just had to add number 8
YEAHHHHHH

Pinguino99 · 12-11-2019, 04:08 PM

pan64, grail, Turbocapitalist, danielbmartin, dugan, astrogeek
thanks to everyone

grail · 12-12-2019, 06:37 AM

I would also point out that not ALL of your key/value pairs had char/8 chars as some had 9

Code:

    [' ']="111_space"
    ['!']="life_9900"

So this is either an oversight or will cause your idea of grabbing 8 char segments not work.

Also, your original example pointed to the fact that an already encrypted string would come in as separated items:

Code:

decode '@_banana !!_stars computer life_9900'

So here there would be no need to find every 'x' char grouping as they are already separated into segments which bash can work with.

What I am trying to point out here is that you need to be clear in your original problem proposal, otherwise you are overcomplicating the problem and
the solution required.

Now that you berlieve you have a solution, would you repost with the correct arrays and code so others may learn from you?
Might also be nice to re-enter the original problem spec so people can follow why your solution is correct.

Pinguino99 · 12-12-2019, 10:02 AM

Code:

#!/usr/bin/env bash

declare -A encrypt=(
    [A]="AAAAAAAA"
    [B]="BBBBBBBB"
    [' ']="-0-0-0-0"
    ['!']="!!!!!!!!"
)

declare -A decrypt=(
    [AAAAAAAA]="A"
    [BBBBBBBB]="B"
    ['-0-0-0-0']='-0-'
    ['!!!!!!!!']="!"
)

encode () {
    local word=$1
    for ((i=0; i<${#word}; ++i)) ; do
        local char=${word:$i:1}
        printf %s ${encrypt[$char]}
    done
    printf '\n'
}

decode () {
    local word=$1
    for ((i=0; i<${#word}; ++i)) ; do
        local char=${word:$i:8}
        printf %s ${decrypt[$char]}
    done
    printf '\n'
}

echo "encrypt"
encode 'AB !'

echo "decrypt"
decode 'AAAAAAAABBBBBBBB-0-0-0-0!!!!!!!!'

yes it only reads 8 characters or 1, I have little knowledge in shell script so, i don't know how to make ${word} recognize any number of characters
the solution I found was to adapt the cipher

Pinguino99 · 12-12-2019, 11:21 AM

Code:

#! /bin/bash
declare -A crypt=(
    [A]="99_banana"
    [a]="@_melon"
    [B]="22_GRAPE"
    [b]="orange"
    [C]="Strawberry"
    [c]="life"
    [' ']="space"
    ['@']="12399"
    ['!']="tv_12"
)

encode () {
    local word=$1
    for ((i=0; i<${#word}; ++i)) ; do
        local char=${word:$i:1}
        printf %s ${crypt[$char]}
    done
    printf '\n'
}

declare -A decrypt
for char in "${!crypt[@]}" ; do
    key=${crypt[$char]}
    decrypt[$key]=$char
done

decode () {
    local word=$1
    while [[ $word ]] ; do
        local code
        for code in "${!decrypt[@]}"; do
            if [[ $word == "$code"* ]] ; then
                printf %s "${decrypt[$code]}"
                word=${word#"$code"}
            fi
        done
    done
    printf '\n'
}

encrypt=$(encode 'Abc !')

decrypt=$(decode "$encrypt")

echo "$encrypt"

echo "$decrypt"

working perfect

grail · 12-12-2019, 11:28 AM

So now that you have it working, don't forget to mark the thread as SOLVED

Here was my take on the bash solution which is mostly like yours but with a single array:

Code:

#!/usr/bin/env bash

declare -A gA_cipher

gA_cipher=( [A]="@_banana"
         [a]="99_melon"
         [B]="AZ_GRAPE"
         [b]="!!_stars"
         [C]="81_xxxxx"
         [c]="computer"
         [ ]="11_space"
         [!]="life_900"
       )

usage()
{
  echo "Correct usage:- ${0##*/} [-e|-d] strings"
  exit 1
}

decrypt()
{
  local ls_words
  local ln_num_chars ln_cnt
  local lb_not_found
  local lc_char

  ls_words=$*
  ln_num_chars=8

  for ((ln_cnt = 0; ln_cnt < ${#ls_words}; ln_cnt = ln_cnt + ln_num_chars ))
  do
    for lc_char in "${!gA_cipher[@]}"
    do
      if [[ "${gA_cipher[$lc_char]}" == "${ls_words:ln_cnt:ln_num_chars}" ]]
      then
        echo -n "$lc_char"
        lb_not_found=false
        break
      else
        lb_not_found=true
      fi
    done
    $lb_not_found && echo -n "##no_value##"
  done
}

encrypt()
{
  local ls_words
  local ln_cnt

  ls_words=$*

  for ((ln_cnt = 0; ln_cnt < ${#ls_words}; ln_cnt++ ))
  do
    if [[ "${gA_cipher[${ls_words:ln_cnt:1}]}" ]]
    then
      echo -n "${gA_cipher[${ls_words:ln_cnt:1}]}"
    else
      echo -n "##no_value##"
    fi
  done
}

(( $# < 2 )) && usage

case $1 in
  -d) decrypt "${@:2}";;
  -e) encrypt "${@:2}";;
   *) usage;;
esac

echo