读取文本文件中的第n行并在MS Batch中进行处理

Question

Well.. What I need to is actually just to read the n-th line of a cleartext file and save in a variable to process it further within the batch. So I have been googling quite maaany hours and found many solutions (all in a for loop). Also many here on Stack Overflow, but well, none worked for me.

Here is an example of one way I tried out

for /f "skip=%toskip%" %%G IN (passwd.txt) DO if not defined line set "line=%%G"

So here the details on my project.

contents: pwcracker.bat (shown in the following)
requires: 7za.exe, passwd.txt (a database with 1 possible password on each line)

pwcracker.bat:

    @echo on

    for /f %%i in ("passwd.txt") do set size=%%~zi
    if %size% leq 0 (
     echo Please create a dictionary of passwords first [File not found: passwd.txt]!>result.txt
     exit 1
    )

    @Overwrite result.txt if it exists
    echo [RESULT]>result.txt

    @Try to delete the log if it exists
    IF EXIST logging.txt del /F logging.txt

    @REM If the file wasn't deleted for some reason, stop and error
    IF EXIST logging.txt (
     echo The log file must be removed!>>result.txt
     exit 1
    )

    @Ask user for the file to unzip
    set /p filename=Enter 7z filename [name.7z]:

    @Check amount of PWs to try within the dictionary
    cls
    setlocal EnableDelayedExpansion
    set "cmd=findstr /R /N "^^" passwd.txt | find /C ":""

    @Set the amount to try
    for /f %%a in ('!cmd!') do set tries=%%a

    @####################################

    @Begin the for loop to try all PWs until unzipped or all PWs are tried
    FOR /L %%X IN (1,1,%tries%) DO (

     @Set PW to try
     @CODE INPUT TO READ AND STORE PW in local variable %passwd%

     @try to unzip using the given password and log the output
     7za e %filename% -o%CD%\unzipped -p%passwd%>>logging.txt

     @check the size of the log file
     for /f %%i in ("logging.txt") do set size=%%~zi

     @see whether it was succesful and log the tried password in the resuts
     findstr /m "Error" logging.txt
     if %errorlevel%==1 (
      echo It didn't work with PW: %passwd%>>result.txt

      @Try to delete the log if it exists
      IF EXIST logging.txt del /F logging.txt

      @REM If the file wasn't deleted for some reason, stop and error
      IF EXIST logging.txt (
       echo The log file couldn't be removed!>>result.txt
       exit 1
      )
      @end of error-check clause
     ) 


     else (
      if %size% leq 0 (
      echo Something went wrong, please check manually>result.txt
      echo Tried PW : %passwd% >>result.txt
      exit 1
     )
    @end of prior else block
    )

    else (
     echo Unzipped succesfully with PW: %passwd%>result.txt
    exit 1
    )

   @end of for loop (1,1,tries)
   )

This batch file will basically just "crack" my aes-encrypted 7zip file as I have mistyped the password and don't know what it is for certain. And yeah, tools like 7zcracker don't work and end up stating "The passwod was 1" btw, but this "tool" can see whether there was an "Error" while unzipping, or not (since only the data is encrypted and not the names, the 7z file can be "unzipped", but the contents' size is 0 ofc)

Answer 1

You don't need to get the number of tries . Just read each line in the password file.

FOR /F "usebackq tokens=*" %%p IN (`TYPE passwd.txt`) DO (
    ECHO Trying password %%p
    REM try the password
)