nehm is a console tool, which downloads, sets IDv3 tags (and adds to your iTunes library) your SoundCloud posts or likes in convenient way. See homepage for instructions

Read and write ID3 metadata from/to MP3 files

A command-line tool for reading and writing audio metadata.

Library for reading embedded star-ratings in audio files. Supports file formats: AIFF, FLAC, M4A, MP3, Ogg and WAV. Uses library TagLib and Ruby interface taglib-ruby.

Small utility for finding inconsistencies among audio files organized in "album" directories

AutoTune is a library that automates the task of adding metadata to music with the help of the iTunes Affiliates Search API.

Batch Audio Convert

tool to convert keys in mp3s

ID3v1 tag processing for CarrierWave uploads

A console music library explorer and player

Wraps common audio-related tasks into Dragonfly analysers and processors.

EasyTag is an abstract interface to the TagLib audio tagging library. It is designed to provide a simple and consistent API regardless of file format being read.

Utilities for EHB/RS's Ruby projects.

An experimental application for indexing your music library in ElasticSearch

Loose collection of CLI commands to sort and process Flac files

Commandline interface and library to the Fox Scientific Paper Suite

Create playlists by applying customized search filters to a set of audio files.

Access iPod Shuffle 2nd gen from ruby

lllibrary is a Ruby library for managing and querying a music library.

Parse media file metadata, copy or transcode mediafiles.