CrossRename 1.5.0

Harmonize file and directory names for Linux, Windows and macOS.

Harmonize file and directory names for Linux, Windows, and macOS.

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Table of Contents

• Introduction

• Features

• Installation

• Usage

  • Examples

  • Unicode Alternatives Mode

  • Safety First

• Platform Compatibility

• Why did I build this?

• Contributing

• Wait a minute, who are you?

• License

• Changelog

Introduction

CrossRename is a command-line tool designed to harmonize file and directory names across Linux, Windows, and macOS systems. It ensures that your file names are compatible with all three operating systems, eliminating naming conflicts when transferring files between different environments.

Features

• Sanitizes file names to be Windows-compatible (and thus Linux-compatible and macOS-compatible)

• Byte-aware filename truncation (correctly handles CJK, Cyrillic, emoji, and other multi-byte UTF-8 characters)

• Option to replace forbidden characters with Unicode lookalikes instead of removing them

• Optionally renames directories to be cross-platform compatible

• Handles both individual files and entire directories

• Supports recursive renaming of files in subdirectories

• Preserves file extensions, including compound extensions like .tar.gz

• Provides informative logging

• Provides a dry-run mode to preview renaming changes without executing them

• Interactive safety warnings with option to skip for automation

• Skips recursive symlinks to avoid infinite loops

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Installation

From PyPI (Using PIP)

pip install CrossRename

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Usage

usage: crossrename [-h] [-p PATH] [-v] [-u] [-r] [-d] [-D] [-a] [--force] [--max-filename-bytes N] [--credits]

CrossRename: Harmonize file and directory names for Linux, Windows and macOS.

options:
  -h, --help                  show this help message and exit
  -p, --path PATH             The path to the file or directory to rename.
  -v, --version               Prints out the current version and quits.
  -u, --update                Check if a new version is available.
  -r, --recursive             Rename all files in the directory path given and its subdirectories. When used with -D, also renames subdirectories.
  -d, --dry-run               Perform a dry run, logging changes without renaming.
  -D, --rename-directories    Also rename directories to be cross-platform compatible. Use with caution!
  -a, --use-alternatives      Replace forbidden characters with Unicode lookalikes instead of removing them. May cause display issues on some systems.
  --force                     Skip safety prompts (useful for automated scripts)
  --max-filename-bytes N      Maximum filename length in bytes (default: 255, valid range: 4-255).
  --credits                   Show credits and support information

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Examples

Rename a single file:

crossrename -p /path/to/file.txt

Rename all files in a directory (and its subdirectories):

crossrename -p /path/to/directory -r

Rename all files AND directories recursively:

crossrename -p /path/to/directory -r -D

Rename a single directory:

crossrename -p /path/to/problematic_directory -D

Perform a dry run to preview renaming changes without executing them:

crossrename -p /path/to/directory -r -D -d

Skip safety prompts for automated scripts:

crossrename -p /path/to/directory -r -D --force

Use Unicode alternatives instead of removing characters:

crossrename -p /path/to/file.txt -a

Check for an update:

crossrename -u

Show credits and project information:

crossrename --credits

Limit filename length for Linux filesystems (useful for CJK or emoji-heavy filenames):

crossrename -p /path/to/directory -r --max-filename-bytes 255

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Unicode Alternatives Mode

Use –use-alternatives to replace forbidden characters with similar Unicode characters instead of removing them:

crossrename -p "file<name>.txt" --use-alternatives
 # Result: "fileᐸnameᐳ.txt" instead of "filename.txt"

Character mappings:

• < → ᐸ (Canadian Syllabics Pa)

• > → ᐳ (Canadian Syllabics Po)

• : → ∶ (Ratio)

• " → ʺ (Modified Letter Double Prime)

• / → ∕ (Division Slash)

• \ → ⧵ (Reverse Solidus Operator)

• | → ∣ (Divides)

• ? → ﹖ (Small Question Mark)

• * → 🞱 (Bold Five Spoked Asterisk)

Warning

These Unicode characters may not display correctly on all systems, fonts, or applications.

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Safety First

Warning

Always run with --dry-run first!

CrossRename will show interactive safety warnings before making any changes to help prevent accidental data loss. However, it’s strongly recommended to:

1. Run a dry run first to preview what will be changed:

   crossrename -p /your/path -r -D -d

2. Backup your data before running the tool on important files

3. Use --force flag for automation in CI/CD pipelines:

   crossrename -p /your/path -r -D --force

Directory renaming is particularly powerful and potentially disruptive since it changes folder paths that other applications might reference.

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Platform Compatibility

CrossRename works on:

• Windows

• Linux

• macOS

The tool sanitizes filenames to be compatible with the most restrictive filesystem (Windows), ensuring files work everywhere. This means:

• Removing Windows-forbidden characters: < > : " / \ | ? *

• Handling Windows reserved names: CON, PRN, AUX, NUL, COM1-9, LPT1-9

• Removing trailing spaces and periods

• Removing control characters

• Limiting filenames to 255 bytes (for ext4/btrfs compatibility; configurable via --max-filename-bytes)

Note

Prior to v1.5.0, CrossRename limited filenames to 255 characters, which could still produce filenames that fail on Linux. ext4 and btrfs enforce a 255 byte limit, not a character limit. Since non-ASCII characters in UTF-8 occupy more than one byte, the effective character limit is lower:

Script	Bytes per char	Effective limit
Latin (ASCII)	1	~255 characters
Cyrillic	2	~127 characters
CJK (Chinese, Japanese, Korean)	3	~85 characters
Emoji	4	~63 characters

v1.5.0 fixes this with byte-aware truncation. If you have files that were previously “within the limit” but still fail to copy to a Linux filesystem, re-run CrossRename to truncate them correctly.

Since Windows has the strictest rules, files renamed by CrossRename will work on Linux and macOS without issues.

Important

If files were created on Linux or macOS with Windows-forbidden characters (like <, >, :, etc.), Windows cannot see those characters—the filenames appear mangled or stripped. To fix these files, you must run CrossRename from the originating OS (or WSL for Linux files), not from Windows.

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Why did I build this?

So I was dual-booting Windows 10 and Lubuntu 22.04, and one day I’m trying to move some files between the two systems. Five files just wouldn’t copy over because of what I later found out were the differences in Windows and Linux’s file naming rules.

That got me thinking because I’d already built a Python package that had to deal with some file creation and renaming ( It’s called FicImage, please check it out 🫶) before, so I had an idea or two about how to go about this.

Long story short, I got annoyed enough to build CrossRename. Now I don’t have to deal with file naming headaches when switching between systems.

Note

I’m no longer dual booting. I’m using Windows 11 now. I do have WSL2 and that’s what I use for testing. I don’t know if there’ll be any difference in the way the tool works on a native Linux system.

macOS support is theoretical but should work since the tool uses the most restrictive ruleset (Windows).

If you test on macOS, please report any issues!

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Contributing

Contributions are welcome! If you’d like to improve CrossRename please feel free to submit a pull request.

Especially welcome:

• macOS/APFS testing and feedback (currently untested on real macOS hardware)

• Linux testing and feedback (on native linux)

• Edge case handling for Unicode normalization differences

• Performance improvements for large directory trees

• Other Operating Systems

• Any other thing I forgot to list here

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Wait a minute, who are you?

Hello there! I’m Emmanuel Jemeni, and while I primarily work as a Frontend Developer, Python holds a special place as my first programming language. You can find me on various platforms:

• LinkedIn

• GitHub

• BlueSky

• Twitter/X

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License

MIT License

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Changelog

Changelog

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