batch-file-rename

Batch File Rename

Safely rename multiple files with preview-first semantics.

When to use it

• Standardize filenames across a directory (e.g., all lowercase, spaces → underscores)
• Add sequential numbers (photo_001.jpg, photo_002.jpg, …)
• Add prefixes or suffixes to batches of files
• Replace patterns in filenames (e.g., draft_ → final_)
• Change extensions in bulk (.JPG → .jpg, .md → .txt)
• Revert accidental renames via generated undo script

Prerequisites

• bash 4+
• python3 (optional, for Unicode-safe slugify)
• No external dependencies required

Quick Start

1. Dry-run (always do this first)

bash scripts/batch-rename.sh --dir /path/to/files --dry-run

Output example:

[DRY-RUN] photo 1.JPG → photo_001.JPG
[DRY-RUN] photo 2.JPG → photo_002.JPG
[DRY-RUN] photo 3.JPG → photo_003.JPG
3 files will be renamed

2. Add sequential numbers

bash scripts/batch-rename.sh --dir ./photos --number --prefix "vacation_" --start 1 --digits 3

3. Pattern substitution

bash scripts/batch-rename.sh --dir ./docs --replace "draft_" --with "final_"

4. Change case + extension

bash scripts/batch-rename.sh --dir ./files --lowercase --ext-lower

5. Full options

bash scripts/batch-rename.sh [OPTIONS]

Options:
  --dir DIR        Target directory (required)
  --dry-run        Preview changes without renaming
  --number         Add sequential numbers
  --prefix P       Prepend P to each filename
  --suffix S       Append S before extension
  --start N        Starting number for --number (default: 1)
  --digits N       Pad width for --number (default: 3)
  --replace FROM   Replace FROM pattern in filenames
  --with TO        Replace with TO (default: empty)
  --lowercase      Convert filenames to lowercase
  --uppercase      Convert filenames to uppercase
  --ext-lower      Convert extensions to lowercase
  --ext-upper      Convert extensions to uppercase
  --glob PAT       Only match files matching PAT (default: *)
  --undo FILE      Undo using a previous rename log
  --log FILE       Write rename log to FILE (default: /.rename-log-)
  -h, --help       Show this help

Safety Features

1. Dry-run by default — always preview before committing
2. Collision detection — aborts if two files would get the same name
3. Rename log — every real run writes a log that can --undo
4. No overwrite — refuses to overwrite existing files

Undo

Every real run generates /.rename-log-:

RENAME|photo 1.JPG|photo_001.JPG
RENAME|photo 2.JPG|photo_002.JPG

Undo:

bash scripts/batch-rename.sh --undo ./photos/.rename-log-20260816-231500

Examples

Standardize a download folder

bash scripts/batch-rename.sh --dir ~/Downloads --lowercase --ext-lower --replace " " --with "_"

Number photos for a gallery

bash scripts/batch-rename.sh --dir ./gallery --number --prefix "img_" --digits 4 --start 100

Convert .JPG to .jpg in place

bash scripts/batch-rename.sh --dir ./photos --ext-lower --glob "*.JPG"

Script

See scripts/batch-rename.sh for the full implementation.