Picoglob turns bash-style glob patterns (*, **, ?, [...], {a,b}, {1..3}, and extglobs like @(a|b), +(a|b), !(a|b)) into reusable Ruby Regexps, so you can match arbitrary strings -- S3 keys, routes, log lines, branch names -- not just files on disk. It is the missing Ruby counterpart to JavaScript's picomatch / minimatch. Pure Ruby, no dependencies.