Rename .txt files to first line in file and add "()" to duplicates - batch-file

Question

I am trying to rename 200+ .txt files in a directory with first line of their contents. The files contains IP address in format such as 12.345.678.90. I have found a batch-file which does exactly that, except that the duplicates don't get renamed at all.
I have edited (to my needs), and tested following script on Server2016 and Windows10 Which renames the files but doesn't do anything for duplicates.
#echo off
setlocal EnableDelayedExpansion
rem Multi-thread file rename program
if "%1" equ "Thread" goto ProcessBlock
rem Create the list of file names and count they
cd C:\Renamed_Files
set numFiles=0
(for %%f in (*.txt) do (
echo %%f
set /A numFiles+=1
)) > fileNames.tmp
rem Get number of threads and size of each block
set numThreads=%1
if not defined numThreads (
set /A numThreads=1, blockSize=numFiles
) else (
set /A blockSize=numFiles/numThreads
)
rem Create asynchronous threads to process block number 2 up to numThreads
if exist thread.* del thread.*
for /L %%t in (2,1,%numThreads%) do (
echo %time% > thread.%%t
start "" /B "%~F0" Thread %%t
)
rem Process block number 1
set count=0
for /F "delims=" %%f in (fileNames.tmp) do (
set /p line1=<%%f
ren "%%f" "!line1:~0,40!.txt"
set /A count+=1
if !count! equ %blockSize% goto endFirstBlock
)
:endFirstBlock
rem Wait for all asynchronous threads to end
if exist thread.* goto endFirstBlock
rem Delete the auxiliary file and end
del fileNames.tmp
goto :EOF
rem Process blocks 2 and up (asynchronous thread)
:ProcessBlock
set /A skip=(%2-1)*blockSize, count=0
for /F "skip=%skip% delims=" %%f in (fileNames.tmp) do (
set /p line1=<%%f
ren "%%f" "!line1:~0,40!.txt"
set /A count+=1
if !count! equ %blockSize% goto endBlock
)
:endBlock
del thread.%2
exit
I am hoping to rename .txt files and add () with a number of duplication so the duplicates can still get renamed with the same batch file, (by editing it of course), or a new batch would be needed? any suggestion? or new code is welcome.
Eventually duplicate files can be merged in to one, (as they would be containing the same ip addresses anyway), and then renamed the file to their first line of the content.

Answer 1

With multiple threads, you might have a race condition leading to a collision. The way I would start this is to use the thread number to avoid collisions. I am showing untested example code. Due to the difficulties with parentheses in DOS, I am instead going to use periods and recommend the same to you:
...
:ProcessBlock
set /A skip=(%2-1)*blockSize, count=0
for /F "skip=%skip% delims=" %%f in (fileNames.tmp) do call :ProcessBlockLoop "%%~f" %2
goto :eof
:ProcessBlockLoop
set /p line1=<"%~1"
set "filename=!line1:~0,40!"
:: Check for an existing file.
if not exist "%filename%.txt" goto :ProcessBlockLoopContinue
:: if we get here then there is an existing file.
set DupCnt=1
:ProcessBlockFilenameLoop
if not exist "%filename%.%2.%DupCnt%.txt" (
set filename=%filename%.%2.%DupCnt%
goto :ProcessBlockLoopContinue
)
:: increment our duplicate counter and try again
set /a DupCnt += 1
goto :ProcessBlockFilenameLoop
:ProcessBlockLoopContinue
:: Try the rename. If the rename fails, then reset the variables and loop again.
:: A retry counter should be added to avoid an infinite loop.
ren "%%f" "%filename%.txt" || set DupCnt=1&&set "filename=!line1:~0,40!"&&goto :ProcessBlockFilenameLoop
:: If we're here, the rename should have worked. You could double check again if desired.
set /A count+=1
if %count% equ %blockSize% (
del thread.%2
exit
)
goto :eof