Let's assume we have three groups of files, a, b and c: a1.jpg a2.jpg ... a50.jpg b1.jpg b2.jpg ... b150.jpg c1.jpg c2.jpg ... c20.jpg Let us assume that each group of a, b or c can have at most 999 files. We want these files to be renamed such that: * c files are prefixed with 0-, a files are prefixed with 1-, and b files are prefixed with 2- to create a desired alphabetical order. * The digit components of the filenames are completed to three digits using preceding zeroes if necessary. So the above files would be renamed to the following: 0-c001.jpg 0-c002.jpg ... 0-c020.jpg 1-a001.jpg 1-a002.jpg ... 1-a050.jpg 2-b001.jpg 2-b002.jpg ... 2-b150.jpg How would one go about doing this with a batch file? Thanks.

Hi Try This I inserted echo before the ren command for safety. @echo off setlocal enabledelayedexpansion for /f "tokens=*" %%a in ('dir /b *.jpg') do ( set FName=%%~na set FChar=!FName:~,1! set /a Num=!FName:~1! if !Num! LSS 10 set Num=0!Num! if !Num! LSS 100 set Num=0!Num! if !FChar!==c set NName=0-!FChar!!Num! if !FChar!==a set NName=1-!FChar!!Num! if !FChar!==b set NName=2-!FChar!!Num! echo ren !FName!.jpg !NName!.jpg )

Thank you for your help. The code works great. I especially like the clever bit where you padded the numbers by testing iteratively in two lines. It would have taken me a lot more lines. There was a little bug where, for *.jpg files in the same directory that don't have any of the predetermined prefixes (a, b or c) the batch file tried to name all of them 0-c001.jpg. I think it was doing that because NName was uninitialized and it tried to initialize NName somehow. It doesn't make sense but that's what it did. I fixed it by adding a couple of lines to initialize NName and then test for it as follows: @echo off setlocal enabledelayedexpansion for /f "tokens=*" %%a in ('dir /b *.jpg') do ( set FName=%%~na set NName=!FName! set FChar=!FName:~,1! set /a Num=!FName:~1! if !Num! LSS 10 set Num=0!Num! if !Num! LSS 100 set Num=0!Num! if !FChar!==c set NName=0-!FChar!!Num! if !FChar!==a set NName=1-!FChar!!Num! if !FChar!==b set NName=2-!FChar!!Num! if not !NName!==!FName! echo ren !FName!.jpg !NName!.jpg )

Hi Glad it worked. The extra code you added was also a neat solution. DTech10