RenRe - Batch regex renaming of files and folders

Rename files and folders using regular expressions.


Use the –folder and –rfolder options to add folders to search for files and folders to rename. Use each option as many times as necessary to add different folder hierarchies. Use –search and –replace to specify a regular expressions and a format strings for renaming. Back references are allowed in the format strings.

Regular expressions can be tricky. It’s a good idea to always run the app first with –dry-run just to make sure it will do what you want.

Uses the Perl Regular Expression Syntax.


When using multiple –folder and –rfolder switches, make sure that you are not inadvertently adding the same files multiple times, for instance by adding in a recursive directory and then a subdirectory of that directory. The same file could get renamed multiple times, causing confusing results.

If you get error The application has failed to start because its side-by-side configuration is incorrect or another error about missing DLLs or missing dependencies, download and run vcredist_2010_64.exe or vcredist_2010_32.exe (select the one that corresponds to the 32 or 64 bit version of RenRe that you downloaded). You only have to do this once.

If you get error Not a valid Win32 application, on a 32 bit version of Windows, make sure that you downloaded the 32 bit version of RenRe.

Command line

RenRe - Batch regex renaming of files and folders -
  --help                    produce help message
  -f [ --folder ] arg       add search folder
  -r [ --rfolder ] arg      add recursive search folder
  -s [ --search ] arg       search regex (required)
  -e [ --replace ] arg      replace with (back references allowed) (required)
  -i [ --filter ] arg (=.*) file/folder filter regex
  -d [ --dry-run ]          don't rename anything -- just simulate
  -v [ --verbose ]          display verbose messages
  -c [ --case-sensitive ]   make regexes case sensitive
  -z [ --files-only ]       only rename files
  -x [ --folders-only ]     only rename folders
  -q [ --query ]            ask for confirmation for each rename
  -l [ --depth ] arg        limit depth of recursive search

  The search and replace arguments can be given without using options, as long
  as they are given in that order.


Rename all files and folders in the current folder to all UPPER CASE:

renre "(.*)" "\U\1"

Rename all files and folders in the current folder to Title Case:

renre "(^.| .)" "\U\1"



  • Use a depth-first recursive algorithm to process the folders and files.
  • First create a list of files to rename and then do all renaming in a separate step to prevent issues that result from changing file and folder names while traversing the folder structure.