Batch script that will insert filenames into files within multiple subfolders - batch-file

Question

I need help creating a batch script that will add the filename to the first line of every .csv within all subfolders. The batch file will be in the mainfolder. The same folder will contain several subfolders, each containing a large amount of .csv files. I need the files to stay within their respective folders. My goal is to add this to another working script I have that merges all files within a subfolder into a single .csv. This will provide a way to navigate through the merged file. I found some similar posts, but they weren't quite what I was looking for. This is the closest thing I could find but the delimiter stuff is throwing me off Batch file to Write Filename to first line
File Structure Example:
C:\MainFolder\batch_script.bat
C:\MainFolder\SubFolder1\csv1.csv
C:\MainFolder\SubFolder1\csv2.csv
C:\MainFolder\SubFolder2\csv3.csv
C:\MainFolder\SubFolder2\csv4.csv
File Contents before running script
csv1.csv:
This is the content of csv1.csv
csv2.csv:
This is the content of csv2.csv
csv3.csv:
This is the content of csv3.csv
csv4.csv:
This is the content of csv4.csv
File Contents after running script:
csv1.csv:
csv1.csv
This is the content of csv1.csv
csv2.csv:
csv2.csv
This is the content of csv2.csv
csv3.csv:
csv3.csv
This is the content of csv3.csv
csv4.csv:
csv4.csv
This is the content of csv4.csv
P.S.
I also found this code on another website but I'm not sure how I would make it loop through the different subfolders
FOR /F "usebackq tokens=1" %%i IN (`DIR /B`) DO (
ECHO %%i >> %1
TYPE %%i >> %1
)

Answer 1

#echo off
setlocal enableextensions disabledelayedexpansion
for /r %%a in (*.csv) do (
set /p "firstLine=" < "%%~fa"
setlocal enabledelayedexpansion
for /f "delims=" %%b in (".!firstLine!") do endlocal & if not "%%~b"==".%%~nxa" (
( echo %%~nxa
type "%%~fa"
) > "%%~fa.new"
move /y "%%~fa.new" "%%~fa" >nul
)
)
What it does is generate a new file with the name of the csv as the first line, appends the csv to the new file and moves the new file over the csv. In the process, it tests if the content of the first line is the same as the name of the csv to avoid reinclusion of the filename on each run of the batch file.
edited to adapt to comments - As the process will not be run more than once for set of csv files, the full code can be reduced to
#echo off
setlocal enableextensions disabledelayedexpansion
for /r %%a in (*.csv) do (
( echo %%~nxa
type "%%~fa"
) > "%%~fa.new"
move /y "%%~fa.new" "%%~fa" >nul
)

Answer 2

Try this:
for /r %%a in (*.csv) do (
copy /y "%%~a" "%temp%\%%~na"
Echo %%~na > "%%~a"
for /f "usebackq" %%b in ("%temp%\%%~na") do Echo %%b >> "%%~a"
del "%temp%\%%~na"
)
And that should do what you want it to. I would test it out first if you could.

Answer 3

This should create an all.csv in every folder in the tree under the C:\MainFolder and add the filename before the contents of each CSV file.
The filename will contain the full path but that can easily be changed if needed.
#echo off
for /d /r "C:\MainFolder\" %%a in (*) do (
pushd "%%a"
(for %%b in (*.csv) do (
echo %%b
type "%%b"
)
)>all.tmp
ren all.tmp all.csv
popd
)
pause