permfix

A fast, safe, and declarative CLI utility written in Nim for recursively setting file and directory permissions.

A Robust File Permission Utility

permfix is a small, fast, and reliable command-line utility written in Nim to recursively set file and directory ownership and permissions. It is designed as a safe and powerful replacement for complex or brittle shell scripts.

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Why permfix?

While chown and chmod shell commands are powerful, creating a script to handle logic for different permission schemes can become cumbersome and error-prone. permfix provides a compiled, type-safe, and explicit alternative that ensures you apply the correct permissions every time, with clear, user-friendly commands.

It's built to be:

• Safe: The tool validates user and group inputs and uses Nim's type system to prevent common errors.
• Explicit: No hidden magic. The commands clearly state their intent.
• Fast: Compiled to a native binary, it operates with maximum efficiency.
• Portable: The final compiled binary has zero dependencies and can be placed anywhere on a Linux/macOS system.

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Features

• Recursively walks directory structures.
• Sets ownership (user and group).
• Applies one of two permission modes:
  • secure: A restrictive mode ideal for private media libraries (750 for dirs, 640 for files).
  • permissive: A more open mode for collaborative group access (775 for dirs, 664 for files).
• Validates that specified user and group exist before making changes.
• Provides clear, verbose output of actions performed.

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Installation

1. Dependencies

permfix requires the cligen library. You can install it using Nim's package manager, nimble:

nimble install cligen

2. Compilation

To build the permfix binary from the perms.nim source file, run the following command. This creates a small, optimized, and static executable.

nim c -d:release --out:permfix perms.nim

3. (Optional) Move to PATH

For system-wide access, move the compiled binary to a directory in your $PATH:

sudo mv permfix /usr/local/bin/

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Usage

⚠️ Important: You must run permfix with sudo or as the root user, as changing file ownership is a privileged operation.

The tool requires a mode (secure or permissive), an owner, a group, and the target path.

Secure Mode

Applies rwxr-x--- (750) to directories and rw-r----- (640) to files. The owner has full control, the group has read-only access, and others have no access.

sudo permfix secure --owner=markus --group=media /path/to/your/movies

Permissive Mode

Applies rwxrwxr-x (775) to directories and rw-rw-r-- (664) to files. Useful when other users or services in the same group need write access.

sudo permfix permissive --owner=markus --group=downloads /path/to/your/games

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License

This project is licensed under the EUPL-1.2 License.