grex
A command-line tool and library for generating regular expressions
... to it, its development was apparently ceased several years ago. The plan is now to add these new features to grex as Rust really shines when it comes to command-line tools. grex offers all features that regexgen provides, and more. The philosophy of this project is to generate the most specific regular expression possible by default that exactly matches the given input only and nothing else. With the use of command-line flags (in the CLI tool) or preprocessing methods (in the library).