rconite is a tool for talking to rcon servers that speak the Source Engine rcon protocol. This includes (at least, in theory) Source games, as well as Minecraft.
To use rconite from the command line, run the included 'rcon' script:
$ rcon --host my-game.example.com --port 56777 boot that annoying player
The actual commands and output depend entirely on the server you connect to. For a full list of options, see 'rcon --help'.
You can also use the 'rconite' module to make rcon calls programmatically. See the module docstring for details.
rcon is an insecure protocol - about as bad as plaintext FTP or Telnet. Passwords are fired around over the network in the clear, without even any obfuscation applied. Using this on the internet with a server you care about is immensely dumb, so don't do it; if you do, and someone swipes your password with Wireshark, don't come whining to me when your server is overrun by griefers.
This code is under the MIT license. You know how to find a copy of it.
Share and enjoy.