Preview a Bulk File Rename
Paste one filename per line, choose a rename rule, and get a deterministic old → new mapping before touching any files.
About this tool
Paste a list of filenames and preview the exact rename mapping before you run a shell script or desktop batch rename. The output is plain old -> new lines, with a collision warning when multiple inputs would produce the same target name.
The tool supports four deterministic rules:
- Find and replace on the filename stem.
- Regex replacement with capture groups such as
$1. - Sequential numbering with
{n},{name}, and{ext}tokens. - Case conversion to lower, upper, title, snake, kebab, camel, or pascal case.
Example:
IMG_001.JPG
IMG_002.JPG
With find IMG and replacement photo, the mapping becomes:
IMG_001.JPG -> photo_001.JPG
IMG_002.JPG -> photo_002.JPG
Limits and edge cases:
- This is a safe preview engine: it never renames local files, uploads a ZIP, or writes an archive.
- Extension preservation is on by default, so transforms apply to the stem and keep
.jpg,.pdf, and similar suffixes. archive.tar.gzpreserves only the final.gzextension;.gitignoreis treated as a dotfile with no extension.- Padding is capped at 20 digits, and blank filename lines are ignored.
FAQ
Does this actually rename my files?
No. It only computes a mapping so you can review the result safely. Use the mapping in your file manager or automation script after checking for mistakes and collisions.
How do regex replacements work?
Choose regex mode, put the regular expression in the find field, and use capture references such as $1 in the replacement field. Invalid regular expressions produce an error instead of a partial mapping.
How do I make photo_001.jpg, photo_002.jpg, and so on?
Choose sequential numbering, set the pattern to photo_{n}, start at 1, set padding to 3, and leave extension preservation enabled.
What happens if two files map to the same new name?
The output still shows every mapping, then adds a collision warning so you can adjust the rule before applying it elsewhere.
Developer & Automation Access
Run it from the terminal
Same engine as this page, headless — via the gizza CLI:
gizza tool bulk-file-renamer "IMG_001.JPG
IMG_002.JPG
My Report File.txt"New to the CLI? Get gizza →
Open it by URL
Pre-fill and auto-run this tool with query parameters — the names match the API/CLI:
https://gizza.ai/tools/bulk-file-renamer/?filenames=IMG_001.JPG%0AIMG_002.JPG%0AMy%20Report%20File.txt&mode=find_replace&find=IMG&replace=photo&case_type=lower&pattern=file-%7Bn%7D&start=1&padding=3&prefix=2026_&suffix=_final&preserve_extension=trueMachine-readable descriptor: tool.json — title + parameters JSON Schema for agents.