suppress chat commands

I have a few chat commands made like this:
[lua]
function restartCommand(ply,text,public)
if( string.sub(text,1,2)=="/r")then
ply:KillSilent()
end
end
hook.Add(“PlayerSay”,“restartCommand”,restartCommand)
[/lua]

is there a way to suppress these commands from being displayed on the client chat box?

return “”