rcon is a command line application that can be used as a Source RCON client. It will send commands to the given server, and print the reply to stdout.

You require libbsd, check, cmake and glib-2.0 to successfully build rcon. You have to install those from your distribution's repository. So for example on Debian you'd do something like this:

$ apt-get install build-essential cmake check libbsd-dev libglib2.0-dev

Then build the project:

$ mkdir build
$ cd build
$ cmake .. -DCMAKE_INSTALL_PREFIX=/usr
$ make
$ sudo make install

A bash-completion script is available, but not installed by default. If you use bash completion simply specify INSTALL_BASH_COMPLETION=ON on the cmake command line:

$ cmake .. -DCMAKE_INSTALL_PREFIX=/usr -DINSTALL_BASH_COMPLETION=ON

The utility comes with a man page: rcon(1). View it with: man 1 rcon.

The command can be called from the command line directly, like so:

$ rcon -H somehost -p someport -P somepass status

rcon automatically concats all your arguments together into one command:

$ rcon -H somehost -p someport -P somepass sm plugins list

This sends the command "sm plugins list" to the server.

If you wish to send more than one command to the server, don't specify one on the command line. Instead give rcon a list of commands through standard input:

$ rcon -H somehost -p someport -P somepass <<EOS
status
sm plugins list
# This might be long!
cvarlist
EOS

In this mode lines starting with # are ignored. This allows rcon to be used as a script interpreter. Just pass it the script file through stdin:

$ cat somescript.txt
# This is a comment
status

# and this too!
sm plugins list

cvarlist

And execute your script like this:

$ rcon -H somehost -p someport -P somepass < somescript.txt
# Or:
$ cat somescript.txt | rcon -H somehost -p someport -P somepass

The command exit with 0 on success, and some arbitrary non-zero exit code on failure.

You can also store your server credentials in a configuration file. The default location for this file is $HOME/.rconrc. You can specify an alternate configuration file through the -c option. Entries from this configuration file are referenced through the -s option.

Here is an example configuration file:

[somehost]
hostname = 174.53.163.41
port = 27045
password = somepass

Now you can do:

$ rcon -s somehost status

• RCON Protocol Specification