Find and Replace (Encryption)

[Jacob]

I am in the process of making some kind of encrypter and decrypter, for this I need to find and replace letters, for instance "a" will be replaced with "$".

I have already searched around but the topics I have seen are inconclusive, thanks to anybody who offers any kind of support.

I am looking for help on how to find and replace strings in a text file.

[Prince_]

for instance "a" will be replaced with "$".

what if there is $ in the original codes?

[Jacob]

for instance "a" will be replaced with "$".

what if there is $ in the original codes?

It's a text file. It is only meant to contain text. Then if that happens I will replace "a" with "\$1" it was simply an example, to help the person who answers my question.

Besides, then "$" will be replaced with "^&".

[Prince_]

i think you may replace each other in the 26 chars.
e.g.

a->b
b->c
c->d
...
z->a

[Jacob]

You don't get it do you.
I will be replacing only text but I can encrypt that into any symbol.

Code: [Select]

a -> !!
b -> *!
c -> (!
d -> ^!
e -> :!as an example, and to decrypt:

Code: [Select]

!! -> a
*! -> b
(! -> c
^! -> d
:! -> eI would prefer it if you no longer posted if you can provide no help on my topic.

[Prince_]

srr, but what help do you need? i dun follow you...

[Dias de verano]

To replace text in a string, you can use the set command thus

set string=%string:a=b%

where a and b are strings

Code: [Select]

C:\>set string=bab

C:\>set string=%string:a=o%

C:\>echo %string%
bob

C:\>set string=%string:o=eee%

C:\>echo %string%
beeeb

C:\>set string=%string:e=^!%

C:\>echo %string%
b!!!b

[Jacob]

To replace text in a string, you can use the set command thus

set string=%string:a=b%

where a and b are strings

Code: [Select]

C:\>set string=bab

C:\>set string=%string:a=o%

C:\>echo %string%
bob

C:\>set string=%string:o=eee%

C:\>echo %string%
beeeb

C:\>set string=%string:e=^!%

C:\>echo %string%
b!!!b

Thanks you very much, problem solved.
But how would i get this to run through everything in a text file rather than just a variable.

[Dias de verano]

But how would i get this to run through everything in a text file rather than just a variable.

An interesting exercise for you, Jacob.

You can read the text file line by line into a variable using FOR, as I am sure you must know by now. Inside the loop you can do all the string replacements in the line of text, and then write it out to a new file.

[Prince_]

you dun know how to replace a char in a string? ...
then i have to tell you that there are lots of limitations when the cmd.exe dealing with the replacement.
i advise that you give up your complex idea about the encryption, juz use my method.

[Jacob]

But how would i get this to run through everything in a text file rather than just a variable.

An interesting exercise for you, Jacob.

You can read the text file line by line into a variable using FOR, as I am sure you must know by now. Inside the loop you can do all the string replacements in the line of text, and then write it out to a new file.

Sorry, I do not know how to set a line as a variable.

[Dias de verano]

you dun know how to replace a char in a string? ...
then i have to tell you that there are lots of limitations when the cmd.exe dealing with the replacement.
i advise that you give up your complex idea about the encryption, juz use my method.

What method? I don't see any method. Just an idea. Both your idea and Jacob's are equivalent. The classic simple substitution cypher.

[Dias de verano]

But how would i get this to run through everything in a text file rather than just a variable.

An interesting exercise for you, Jacob.

You can read the text file line by line into a variable using FOR, as I am sure you must know by now. Inside the loop you can do all the string replacements in the line of text, and then write it out to a new file.

Sorry, I do not know how to set a line as a variable.

You did on Oct 24th

http://www.computerhope.com/forum/index.php/topic,69075.msg451057.html#msg451057

[Jacob]

Code: [Select]

If in doubt, delims== will always grab the whole line (which is what you want.) Note I used set /a because the 2nd line of the output file
from wmic contains a TAB character after the percentage number, which I wanted to remove

So, I did, thanks, and sorry. 

[Prince_]

Sorry, I do not know how to set a line as a variable.

...

Code: [Select]

C:\>type test.txt
hello
world
C:\>for /f %a in (test.txt) do @set line=%a

C:\>echo %line%
world

[Prince_]

you dun know how to replace a char in a string? ...
then i have to tell you that there are lots of limitations when the cmd.exe dealing with the replacement.
i advise that you give up your complex idea about the encryption, juz use my method.

What method? I don't see any method. Just an idea. Both your idea and Jacob's are equivalent. The classic simple substitution cypher.

what i wanna say is that the Jacob's idea of replacement is too complex to realize, for him especially

[Jacob]

you dun know how to replace a char in a string? ...
then i have to tell you that there are lots of limitations when the cmd.exe dealing with the replacement.
i advise that you give up your complex idea about the encryption, juz use my method.

What method? I don't see any method. Just an idea. Both your idea and Jacob's are equivalent. The classic simple substitution cypher.

what i wanna say is that the Jacob's idea of replacement is too complex to realize, for him especially

Sorry, suddenly because I do not know how to replace strings in a text file, I do not understand the idea of encryption? One, cannot know everything.

[Dias de verano]

what i wanna say is that the Jacob's idea of replacement is too complex to realize, for him especially

What I want to say is that your unhelpful and snooty attitude is not appropriate for this forum.

Jacob, you seem to want to replace each letter of the alphabet with a pair of characters. This is all very well, but you should realise that certain character pairs have special meaning in cmd scripts, particularly if the first character of the pair is a caret (^). For example ^! is replaced by cmd with !

[Jacob]

what i wanna say is that the Jacob's idea of replacement is too complex to realize, for him especially

What I want to say is that your unhelpful and snooty attitude is not appropriate for this forum.

Jacob, you seem to want to replace each letter of the alphabet with a pair of characters. This is all very well, but you should realise that certain character pairs have special meaning in cmd scripts, particularly if the first character of the pair is a caret (^). For example ^! is replaced by cmd with !

Yes, I am currently stuck with the following, I have dinner now, so is it okay if I leave you to ponder around with this?

Code: [Select]

@echo off
set FileName=text.txt
for /f "skip=0 delims==" %%A in ('type %FileName%') do (
set string=%%A
set string=%string:a=o%
echo %string%>!%FileName%
)
pause >nul


[Prince_]

In actual fact, i've done the work about one year before ,which you're doing now. I know how hard it is while replacing some chars.

[Jacob]

In actual fact, i've done the work about one year before ,which you're doing now. I know how hard it is while replacing some chars.

I very much doubt that, or you would of been able to help me, like I said before, I'd prefer it if you do not post on my thread anymore.

[Prince_]

What I want to say is that your unhelpful and snooty attitude is not appropriate for this forum.

unhelpful? snooty?
im trying my best to help him, and if i said something wrong when you think im snooty, i make an apology

[Dias de verano]

Yes, I am currently stuck with the following, I have dinner now, so is it okay if I leave you to ponder around with this?

Code: [Select]

@echo off
set FileName=text.txt
for /f "skip=0 delims==" %%A in ('type %FileName%') do (
set string=%%A
set string=%string:a=o%
echo %string%>!%FileName%
                  ^
             
)
pause >nul


Code: [Select]

echo %string%>!%FileName%
              ^
              |
              |
     Why is this here?


You need to learn about delayed expansion. Variables in a parenthetical expression such as a FOR loop or a block IF structure are not updated because of the way cmd expands variables at runtime. You need to use a special technique...

1. Place this line before the code

setlocal enabledelayedexpansion

2. Use ! signs instead of % signs inside the loop for the variables you wish to change as the loop runs.

Code: [Select]

@echo off
setlocal enabledelayedexpansion
set FileName=text.txt
for /f "skip=0 delims==" %%A in ('type %FileName%') do (
set string=%%A
set string=!string:a=o!
echo !string!>%FileName%
)
pause >nul
You do know that your code will only work if the file %FileName% contains exactly one line?

[Jacob]

Thank you, but I get:

Code: [Select]

delims==" was unexpected at this timeand the

Code: [Select]

echo %string%>!%FileName%was there to differentiate a crypted file and a non crypted file.

And i am aware that this will only work for one line, but i am planning on looping it much like this:

Code: [Select]

:loop
find /c " " data\accounts\%AccName%\bank.txt>data\temp\linecount\%AccName%.txt
for /f "tokens=1,2,3 delims= " %%A in ('type data\temp\linecount\%AccName%.txt ^| find "BANK.TXT:"') do (
    set count=%%C
    )
set /a id=%id%+1
for /f "tokens=1,2,3 delims=:" %%A in ('type data\accounts\%AccName%\bank.txt ^| find "=%id%="') do (
    set itemidno=%%B
set itemq=%%C
    )
for /f "tokens=1,2,3 delims=:" %%A in ('type data\item\items.txt ^| find "ID=%itemidno%="') do (
    set itemn=%%B
set itemp=%%C
    )
set /a itemw=%itemp%*%itemq%
echo     %itemq% x %itemn% [%itemw%]
if %ID% NEQ %count% (
goto loop
)

[Dias de verano]

Thank you, but I get:

Code: [Select]

delims==" was unexpected at this time

This is because skip=0 is not allowed. You must use a value of 1 or more. If you are skipping 0 lines, omit the skip=N part altogether.

[diablo416]

ive tryed something similar to this, i gave up on it because there was already third party software that would do this from cmd.exe,  the problem i came across in the end is the unknown amount of charachters in the current line,

i thought of another way to do this, but i could never make it work as i dident understand setlocal enabledelayedexpansion well enough, something like this
just as an example

@echo off
set cn=0
setlocal enabledelayedexpansion
for /f "Tokens=1*" %%a in (file) do (
       call set line=%%a%%b
       if "!%line:~!%cn%!,1%!"=="w" set file.%!cn!%=u
       call set /a cn=%!cn!%+1
)

that wont work

[diablo416]

you might also consider, having every charachter on a new line.. for example


@echo off
:TOP
set /p encr=-
set mes=%mes%%encr:~0,1%
echo.&echo %encr:~0,1%>>FILE
CLS&Echo %mes%&Pause>nul & goto TOP

as a way of writting the message to be encrypted then just using if statements

[Dias de verano]

You can get the length of any string by echoing it to a temp file and then using FOR to get the file size, and finally subtracting 2 from that (for the cr and lf at the end)

Code: [Select]

@echo off
set string=123456789
echo %string%>%temp%\getlength.txt
for %%L in (%temp%\getlength.txt) do set /a slen=%%~zL
set /a slen-=2
echo length %slen%
Note: no space between the variable name and the > symbol

[devcom]

i've made sth like encrypting program based on random generated key's
ex of usage:

Code: [Select]

Password: computerhope
Key: 6CLgj9e1rtH4pFuNXDoA7mzqVY82WskB0I3
Generated: 402YDtFz0t

Code: [Select]

Password: computerhope
Key: Z19Es6WG2xFa4yrHctmI5D3UqoV7jNB80L
Generated: a07otxy30x

decrypt work well too

[Dias de verano]

Code: [Select]

@echo off
setlocal enabledelayedexpansion
set string=Mary had a little lamb

REM Get string length
echo %string%>%temp%\getlength.txt
for %%L in (%temp%\getlength.txt) do set /a slen=%%~zL
set /a slen-=2
echo String is %string%
echo String length is  %slen%


REM show each character in the line
for /L %%C in (1,1,%slen%) do (
set /a n=%%C-1
        call set char=%%string:~!n!,1%%
        echo Character %%C   is  !char!
)





[Jacob]

I think i will not continue with this project, but I have learned a few things, thank you everyone.