rap commands:

• = list all open connections
• =<[fd] cmd send output of local command to remote fd
• =[fd] cmd exec cmd at remote 'fd' (last open is default one)
• =! cmd run command via r_io_system
• =+ [proto://]host add host (default=rap://, tcp://, udp://)
• =-[fd] remove all hosts or host 'fd'
• ==[fd] open remote session with host 'fd', 'q' to quit
• =!= disable remote cmd mode
• !=! enable remote cmd mode