references.yml

hosts:
    a:
        addr: a.edu
        ssh:
            user: my_username_on_a
    b:
        addr: b.edu

programs:
    echo:
        # Hosts can be specified by referring to a host label
        host: a
        start: echo '{to_echo}'

    cat:
        # A list of host labels...
        host: [a, b]
        start: cat '{filename}'

    sleep:
        # Or by specifying the host in-line
        host:
            addr: c.edu
            ssh:
                user: my_username_on_c
        start: sleep {duration}


commands:

    # Similarly, commands may refer to program by name
    - program: cat
      filename: 'my_file'
      begin: 0

    # Or by defining them inline
    - program:
        start: 'ls ~'
      host: b
      begin: 5