Whit
You can read the parameters that a player writes on their console..
The first parameter:
means the number of parameter that you read. (0 = command)
But, i think that he want to know how to put off or on a plugin with a cvar.
You have to ask in each function if the cvar is 1 or 0.
PHP Code:
if (!get_pcvar_num(yourcvar)) // If cvar is "0"
return PLUGIN_HANDLED // You "exit" the plugin
//Else, the plugin continues