[antonio112]

Using this callback:

pawn Код:

public OnPlayerCommandText(playerid, cmdtext[])
{
    return 0;
}

Instead of return 0; you put whatever you want. Example:

pawn Код:

public OnPlayerCommandText(playerid, cmdtext[])
{
    return SendClientMessage(playerid, -1, "This command does not exist. Use /help for a full list of commands.");
}