diff --git a/src/main.rs b/src/main.rs
index 7767b69..3d4661d 100644
--- a/src/main.rs
+++ b/src/main.rs
@@ -97,6 +97,15 @@ struct Args {
     )]
     console_addr: SocketAddr,
 
+    /// Dump internal data.
+    #[clap(
+        long,
+        help_heading = "Debugging",
+        value_name = "DATA",
+        value_parser = ["cdef"]
+    )]
+    dump: Vec<String>,
+
     /// Print version.
     #[clap(long, short = 'V')]
     version: bool,
@@ -198,6 +207,11 @@ fn init_tokio(args: &Args) -> tokio::runtime::Runtime {
 
 fn init_lua(args: &Args) -> lb::runtime::Runtime {
     let rt = lb::runtime::Builder::new();
+
+    if args.dump.iter().find(|s| *s == "cdef").is_some() {
+        print!("{}", rt.registry());
+    }
+
     let mut rt = rt.build().unwrap_or_else(exit_err(ExitCode::Software));
 
     for arg in args.jit.iter() {