anneal

Native case-insensitive directories on Linux

anneal turns any Linux directory case-insensitive by backing it with a real ext4 filesystem formatted with the kernel's built-in casefold option. Your files stay put. Your apps stop caring about case.

About

• Kernel-native — no FUSE overlay, no userspace translation. Full ext4 performance at every read and write.
• Non-destructive — anneal stashes your existing files, mounts the new image, and restores them automatically. Nothing is lost.
• Conflict-aware — before mounting, anneal scans for case-colliding files and lets you resolve them interactively.
• Persistent — mounts are written to /etc/fstab automatically on creation and survive reboots without any extra steps.

How it works

anneal creates a sparse ext4 disk image with -O casefold enabled, loop-mounts it over your target directory, and sets the casefold attribute. The result is a real ext4 filesystem where File.txt and file.txt are the same file — resolved at the kernel level, not through a compatibility shim.

Requirements

• python3
• e2fsprogs >= 1.45 (mkfs.ext4, debugfs)
• losetup, findmnt

Install

./install.sh

To uninstall:

./install.sh --uninstall

Uninstalling removes /opt/anneal, /usr/local/bin/anneal, and the udev rule. Your images and data in /var/lib/anneal/ are left intact.

Commands

Command	Description
select <directory>	Set the active directory for subsequent commands
create [directory]	Create a casefold mount and add it to /etc/fstab
remove [directory]	Unmount and remove the image, preserving all files
list	Show all anneal mounts with status
fix	Clear ghost volumes from Nautilus

Example

anneal create ~/Documents/sbox-public

Or select first and reuse:

anneal select ~/Documents/sbox-public
anneal create