Lexurgy is a sound change applier. It allows the user to simulate historical changes in spoken languages by applying regular rules to a list of words.
It's available as a command-line tool and as a web app. The web interface is in a separate repo. The new web interface is in another repo.
The command-line tool requires Java 8 or higher to be installed on your computer. You can get Java here.
To install the command-line tool, download the ZIP or TAR from the releases page, unpack it, and add the bin folder to your PATH. You should now have a lexurgy command available in your terminal; test it by running lexurgy --help, which should display basic usage instructions.
You can read the documentation here.
Lexurgy is written in Kotlin, and the sound change file format is powered by the ANTLR parser generator.