How to create a unique output filename for Windows Script? - windows

Question

I am trying to create a windows script that should generate this kind of filename everytime I run it: filename1, filename2, filename3 and so on. Here is what I have so far:
(
#echo off
wmic logicaldisk get size,freespace,caption
) > disk.txt
I hope you can help me. Thanks!!

Answer 1

:: make a tempfile
:maketemp
SET "tempfile=%temp%\%random%"
IF EXIST "%tempfile%*" (GOTO maketemp) ELSE (ECHO.>"%tempfile%a")
You now have any number of filenames available.
%tempfile%a exists and is empty, but %tempfile%anythingelse should be available for use.
#ECHO OFF
SETLOCAL
SET "basename=filename"
SET /a outname=0
:genloop
SET /a outname+=1
IF EXIST "%basename% %outname%.txt" GOTO genloop
SET "outname=%basename% %outname%.txt"
ECHO %outname%
GOTO :EOF
Ah - increment the destination filename on each run. This should do that. It's not actually creating a file - you'd need to create the file %outname% each time to have it increment...
(the space between %basename% and %outname% is optional, of course - omit it if desired.)
edited to include .txt

Answer 2

This will give you up to 1000 filenames but you can go higher, up to 2 Billion, but the higher you go the longer the delay will be before it picks a filename.
#echo off
for /L %%a in (1,1,1000) do if not defined filename if not exist "filename%%a.txt" set "filename=filename%%a.txt"
(
wmic logicaldisk get size,freespace,caption
) > "%filename%"

Answer 3

#echo off
setlocal enableextensions
call :getNextFilename "filename*.txt" nextFilename
echo %nextFilename%
echo test > "%nextFilename%"
call :getNextFilename "%cd%\filename*.txt" nextFilename
echo %nextFilename%
echo test > "%nextFilename%"
endlocal
exit /b
:getNextFilename whatToSearch returnVariable
setlocal enableextensions enabledelayedexpansion
for /f %%a in ("$\%~1"
) do for /f "tokens=1,* delims=*" %%b in ("%%~nxa"
) do ( set "left=%%b" & set "right=%%c" )
set "max=0"
for %%a in ("%~1"
) do for /f "tokens=1 delims=%left%%right% " %%b in ("%%~nxa"
) do for /f "tokens=* delims=0 " %%c in ("0%%~b"
) do if %%~c geq !max! set /a "max=%%c+1"
endlocal & set "%~2=%~dp1%left%%max%%right%" & exit /b
This should find the next file in sequence independently of the existence of holes in the numeration of the files. A path can be included or omitted. The * will be used as the placeholder for the numeration. BUT this will not work if files or included paths have "problematic" characters.
If the date/time of creation of the file can be considered, then this version can be optimized as
:getNextFilename whatToSearch returnVariable
setlocal enableextensions disabledelayedexpansion
for /f %%a in ("$\%~1"
) do for /f "tokens=1,* delims=*?" %%b in ("%%~nxa"
) do ( set "left=%%b" & set "right=%%c" )
set "max=0"
for /f "delims=" %%a in ('dir /tc /o-d /b "%~1" 2^>nul'
) do for /f "tokens=1 delims=%left%%right% " %%b in ("%%~nxa"
) do for /f "tokens=* delims=0 " %%c in ("0%%~b"
) do set /a "max=%%c+1" & goto done
:done
endlocal & set "%~2=%~dp1%left%%max%%right%" & exit /b
that will take the latest created instance of the file set.

Answer 4

I finally figured out where to put the .txt extension. This is from #Magoo's answer but I wanted the file to be a text file so I placed the .txt twice in order for it to work properly.
#ECHO OFF
SETLOCAL
SET "basename=DISK-OUT"
SET /a outname=0
:genloop
SET /a outname+=1
IF EXIST "%basename% %outname%.txt" GOTO genloop
SET "outname=%basename% %outname%.txt"
(
wmic logicaldisk get size,freespace,caption
) > "%outname%"
GOTO :EOF