source: TFP-WebServer/CommandExtensions/src/Commands/SayToPlayer.cs@ 447

using System.Collections.Generic;
using JetBrains.Annotations;

namespace CommandExtensions.Commands {
        [UsedImplicitly]
        public class SayToPlayer : ConsoleCmdAbstract {
                protected override string getDescription () {
                        return "send a message to a single player";
                }

                protected override string getHelp () {
                        return "Usage:\n" +
                               "   pm <player name / steam id / entity id> <message>\n" +
                               "Send a PM to the player given by the player name or entity id (as given by e.g. \"lpi\").";
                }

                protected override string[] getCommands () {
                        return new[] {"sayplayer", "pm"};
                }

                private void RunInternal (ClientInfo _sender, List<string> _params) {
                        if (_params.Count < 2) {
                                SdtdConsole.Instance.Output ("Usage: sayplayer <playername|entityid> <message>");
                                return;
                        }

                        string message = _params [1];

                        ClientInfo receiver = ConsoleHelper.ParseParamIdOrName (_params [0]);
                        if (receiver != null) {
                                ChatHelpers.SendMessage (receiver, _sender, message);
                        } else {
                                SdtdConsole.Instance.Output ("Playername or entity ID not found.");
                        }
                }

                public override void Execute (List<string> _params, CommandSenderInfo _senderInfo) {
                        RunInternal (_senderInfo.RemoteClientInfo, _params);
                }
        }
}