How can I set the line a string is found on as a variable, and then find the contents of that line number in another file? - variables

Question

Okay, this is kind of complicated so ill try to explain it as best as is can.
I am currently writing a simple program for my own use using notepad.
I am using the language batch and running the program through Command Prompt.
Part of the Program lets you access an account you created with username and password:
set /p USERNAME1= Username?
findstr /n "%USERNAME1%" Usernames.txt
In Usernames.txt are the usernames of each account that has been created, one per line.
If your username is found, it is displayed along with the line number before it in the program.
It then asks for your password:
set /p PASSWORD1= Password?
This is where the problem starts. When the accounts are created, the usernames are stored, one per line, in Usernames.txt , and so are the passwords but in Passwords.txt
I need the program to check if the password you typed is the same as the password on the same line number the username is on, in Passwords.txt
I know this is complicated but if anyone can help it would be greatly appreciated!
Thanks

Answer 1

You're using findstr /N to get the line number of usernames.txt, which is a good start. You're getting the entire line, prefixed with the line number and a colon :.
So for /F can be used to extract the number only. The option string "tokens=1 delims=:" defines to divide the found line at the (first) :, so the line number is separated from the user name.
Finally, another for /F can be used to get the line of the passwords.txt files.
Putting all those things together, the following code snippet emerges:
set /P USERNAME1=Username?
set /P PASSWORD1=Password?
set /A LINENUMBER=0
for /F "tokens=1 delims=:" %%I in (
'findstr /N /I /X /C:"%USERNAME1%" "\path\to\usernames.txt"'
) do (
set LINENUMBER=%%I
goto :CONTINUE1
)
:CONTINUE1
set /A LINENUMBER-=1
if %LINENUMBER% lss 0 (
exit /B
) else if %LINENUMBER% equ 0 (
set SKIPPING=
) else (
set SKIPPING=skip=%LINENUMBER%
)
for /F "usebackq %SKIPPING% delims=" %%I in (
"\path\to\passwords.txt"
) do (
if "%%I" equ "%PASSWORD1%" (
goto :CONTINUE2
)
exit /B
)
:CONTINUE2
rem do something...
So the variable USERNAME1 holds the entered user name to search and PASSWORD1 the entered password.
If the user name cannot be found in usernames.txt, or the entered password does not match the found one, the script is terminated using exit /B.
Note that user names are compared in a case-insensitive manner (/I switch), but the password are compared case-sensitively.