Rename a folder full of files, safely.

1. Installing

Windows. Run frwbSetup-1.0.1.exe. It installs for your user account only, so there is no administrator prompt and nothing lands in Program Files. If you would rather not install anything, take the portable zip instead, unpack it anywhere and run FRWB.exe from the folder.

macOS. Unzip and drag FRWB.app to Applications.

Your settings live in your own user folder and are remembered between sessions: the last folder, the filter, the sort order and every naming setting.

2. Choosing a folder

Press Choose Folder… (or Ctrl+O). Only the files directly in that folder are listed; subfolders are not searched.

• Filter narrows the list. *.jpg; *.png keeps only those. Press Enter to apply it.
• Sort By sets the order of the list, which is also the order the counter counts in. Name uses natural order, so file2 comes before file10. You can also sort by created date, modified date, or the date a photo was taken.
• Check boxes leave a file out. All and None tick or untick everything. An unticked file keeps its name and does not consume a counter value.
• Double-click any row, in either panel, to open that file in whatever application your system uses for it, exactly as the file manager does.

Press F5 if the folder changed behind the application's back.

3. Name Pattern

The pattern is the new name, without its extension. Anything you type is kept exactly as typed, and anything in braces is replaced for each file.

Clicking a token button inserts it at the cursor. The buttons insert rather than switch, which matters more than it sounds: a pattern is ordered and can hold text of your own. {name}_{n} and {n}_{name} are different results from the same two tokens, and Holiday_{n} puts a word you chose in front of every file. Neither survives being reduced to eight on-off switches.

Presets offers ready-made patterns such as {name}_{n} or {date}_{n}. Picking one fills the field and the ticks follow. A token you misspell is left as typed, so you see it in the preview instead of losing it.

4. Name Modifiers

Changes made to the text itself, on either side of the pattern.

• Find and Replace With work on the original name before the pattern reads it, which is why {name} picks up the result. Leave Replace With empty to delete the text.
• Name Case applies to the finished name: keep, lower, UPPER or Title Case.
• Extension changes the case of the extension only. The extension itself is always kept.

5. Number In Name

Cameras and downloads number things: IMG_0042.jpg, Scan 12.pdf. This box says what happens to that number.

Which One picks the last or the first number when a name holds several, as in 2024_pic_07.

6. Counter and Date

Counter has a start, a step and a number of digits, so 3 digits gives 001. It runs in the order of the list and skips unticked files. The step can be negative to count down, and it steps straight over zero, which would hand every file the same name.

Date takes its Source from the file's created date, its modified date, the photo's EXIF date, or a custom date and time you pick. The Format uses the usual strftime codes: %Y year, %m month, %d day, %H hour, %M minute, %S second.

The greying happens in stages, because these are not one switch:

So a pattern of {created} leaves Format live and greys Source: you can change how the date is printed, but not which date it is.

7. Reading the preview

The right panel is colour-coded, and the line under the two lists counts each kind.

Hover any name for the reason. Rename Files stays disabled while a single conflict or invalid name remains, and takes colour the moment the batch can run.

8. Renaming and undo

Press Rename Files (Ctrl+R) and confirm. The work happens off the interface thread, so the window stays responsive on a large folder.

Renaming runs in two phases: every file first moves to a temporary name, then to its final one. That is what lets a batch swap two names, or renumber a series in place, without one rename overwriting a file the next one still needs. A file that unexpectedly cannot be renamed is reported and put back, never replaced.

File › Undo Last Rename (Ctrl+Shift+Z) returns every file in the last batch to its previous name. Only the most recent batch is kept.

9. Theme and manual

Help › Theme chooses light, dark, or whatever your system is set to, which is the default. Every icon in the application is drawn twice so it reads on either.

Help › User Manual (F1) opens this manual on GitHub, and falls back to the copy inside the application when there is no network.

10. Troubleshooting

Rename Files is greyed out

Something in the right panel is red or orange, or no name would actually change. Hover the button for the reason it gives.

The counter or date boxes are greyed out

Nothing in the new name uses them. Add {n} or a date token to the pattern, or set Existing Number to replace with one. See Counter and Date.

A photo has no EXIF date

FRWB reads the date from JPEG and TIFF headers. Other formats, including HEIC and camera raw files, fall back to the file's modified date, and the preview says so when you hover the name.

Some files were not renamed

A dialog lists each one and why. The usual cause is a file open in another application. Close it and press F5, then rename again.

I renamed the wrong thing

File › Undo Last Rename, as long as you have not run a second batch over the top.