$ bin/rbx -S merb --help
Usage: merb [uGdcIpPhmailLerkKX] [argument]
Merb. Pocket rocket web framework
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If no flags are given, Merb starts in the foreground on port 4000.
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    -u, --user USER                  This flag is for having merb run as a user other than the one currently logged in. Note: if you set this you must also provide a --group option for it to take effect.
    -G, --group GROUP                This flag is for having merb run as a group other than the one currently logged in. Note: if you set this you must also provide a --user option for it to take effect.
    -d, --daemonize                  This will run a single merb in the background.
    -N, --no-daemonize               This will allow you to run a cluster in console mode
    -c, --cluster-nodes NUM_MERBS    Number of merb daemons to run.
    -I, --init-file FILE             File to use for initialization on load, defaults to config/init.rb
    -p, --port PORTNUM               Port to run merb on, defaults to 4000.
    -o, --socket-file FILE           Socket file to run merb on, defaults to [Merb.root]/log/merb.sock. This is for web servers, like thin, that use sockets.Specify this *only* if you *must*.
    -s, --socket SOCKNUM             Socket number to run merb on, defaults to 0.
    -n, --name NAME                  Set the name of the application. This is used in the process title and log file names.
    -P, --pid PIDFILE                PID file, defaults to [Merb.root]/log/merb.main.pid for the master process and[Merb.root]/log/merb.[port number].pid for worker processes. For clusters, use %s to specify where in the file merb should place the port number. For instance: -P myapp.%s.pid
    -h, --host HOSTNAME              Host to bind to (default is 0.0.0.0).
    -m, --merb-root /path/to/approot The path to the Merb.root for the app you want to run (default is current working directory).
    -a, --adapter ADAPTER            The rack adapter to use to run merb (default is mongrel)[mongrel, emongrel, thin, ebb, fastcgi, webrick]
    -R, --rackup FILE                Load an alternate Rack config file (default is config/rack.rb)
    -i, --irb-console                This flag will start merb in irb console mode. All your models and other classes will be available for you in an irb session.
    -S, --sandbox                    This flag will enable a sandboxed irb console. If your ORM supports transactions, all edits will be rolled back on exit.
    -l, --log-level LEVEL            Log levels can be set to any of these options: debug < info < warn < error < fatal (default is info)
    -L, --log LOGFILE                A string representing the logfile to use. Defaults to [Merb.root]/log/merb.[main].log for the master process and [Merb.root]/log/merb[port number].logfor worker processes
    -e, --environment STRING         Environment to run Merb under [development, production, testing] (default is development)
    -r ['RUBY CODE'| FULL_SCRIPT_PATH]
        --script-runner              Command-line option to run scripts and/or code in the merb app.
    -K, --graceful PORT or all       Gracefully kill one merb proceses by port number.  Use merb -K all to gracefully kill all merbs.
    -k, --kill PORT                  Force kill one merb worker by port number. This will cause the worker tobe respawned.
        --fast-deploy                Reload the code, but not yourinit.rb or gems
    -X, --mutex on/off               This flag is for turning the mutex lock on and off.
    -D, --debugger                   Run merb using rDebug.
    -V, --verbose                    Print extra information
    -C, --console-trap               Enter an irb console on ^C
    -?, -H, --help                   Show this help message