public OnPlayerConnect(playerid)
{
    new name[24]; // Makes a new string for the name
    GetPlayerName(playerid,name,sizeof(name)); // Assigns it to the name
    // Using strfind, this searches their name for the clan tag and what not.
    if(strfind(name,"[TAG]",true) != -1) // The != is if it was found.
    {
        // If it was found then we follow that if with an other if to check if they are
        // part of the clan that they have in front of their name.
        if(PlayerInfo[playerid][pClan] != 1) // In this case the clan they need to be in is 1
        {
            // If they are not in the clan then it kicks them.
            SendClientMessage(playerid,-1,"You are not in the [TAG] clan, you have been kicked as a result.");
            Kick(playerid);
        }
        else
        {
            // If they are then send them a nice welcome message. :)
            SendClientMessage(playerid,-1,"Welcome back to clan [TAG]");
            return 1;
        }
    }
    return 1;
}

CMD :setclanmember ( playerid , params [ ] )
{
    if ( IsPlayerConnected ( playerid ) )
    {
        if ( IsPlayerAdmin ( playerid ) )
        {
            new
                nom [ MAX_PLAYER_NAME ] ,
                str [ 79 ] ,
                pid
            ;
            if ( sscanf ( params, "u" , pid ) ) return SendClientMessage ( playerid , 0xBEBEBEAA , "[ERROR]: /Setclanmember [playerid]" ) ;
            {
                pClan [ pid ] = pid ;
                GetPlayerName ( playerid , nom , sizeof ( nom ) ) ;
                GetPlayerName ( pid , nom , sizeof ( nom ) ) ;
                format ( str , sizeof ( str ) , "*You Have Successfuly Set %s As An Clan Member!" , pid  ) ;
                SendClientMessage ( playerid , 0x00FF00AA , str ) ;
                format ( str , sizeof ( str ) , "*%s Has Made You A [Du] Clan Member! Now You Are Allowed To Use [DU] Tag in Your Name!" , nom ) ;
                SendClientMessage ( playerid , 0x00FF00AA , str ) ;
            }
        }
        else
            SendClientMessage ( playerid, 0x8B1A1AAA , "[ERROR] Only RCON Administrators Can Use This Command!" ) ;
    }
    else
        SendClientMessage ( playerid , 0x8B1A1AAA , "[ERROR] Player Not Connected!" ) ;
    return 1;
}

CMD:setclanmember(playerid,params[])
{
    new pid; // Your playerid variable.
   // If they are not an admin then return a message saying their not. Take note that returning stops processing
   // the command. The ! is if IsPlayerAdmin returns false, in other words he is not an admin.
   if(!IsPlayerAdmin(playerid)) return SendClientMessage(playerid,0xBEBEBEAA,"[ERROR]: You are not an admin!"):
   // If the player is an admin, then it continues and checks if they typed the command correctly.
   // sscanf automatically says if they didn't type it correctly, so if they they didn't then tell em how to use
   // the command and stop processing it
   if(sscanf(params,"u",pid)) return SendClientMessage(playerid,0xBEBEBEAA,"[USAGE]: /setclanmember [playerid]");
   // Now, if they are an admin, and they typed the command correctly, then we will see if the player that they
   // want to add to the clan is connected. If the pid they typed is not online then it sends them a message telling them so
   if(pid == INVALID_PLAYER_ID) return SendClientMessage(playerid,0xBEBEBEAA,"[ERROR]: Player not found.");
   // Now if everything is correct the 'else' says if everything else has passed, then continue.
   else
   {
        new nom[MAX_PLAYER_NAME],str[79];
        // If everything else has passed then set their clan to 1.
        pClan[pid] = 1;
        GetPlayerName ( playerid , nom , sizeof ( nom ) ) ;
        GetPlayerName ( pid , nom , sizeof ( nom ) ) ;
        format ( str , sizeof ( str ) , "*You Have Successfuly Set %s As An Clan Member!" , pid  ) ;
        SendClientMessage ( playerid , 0x00FF00AA , str ) ;
        format ( str , sizeof ( str ) , "*%s Has Made You A [Du] Clan Member! Now You Are Allowed To Use [DU] Tag in Your Name!" , nom ) ;
        SendClientMessage ( playerid , 0x00FF00AA , str ) ;
        
        // Using strins (string insert) it gets the name string, and adds [DU]
        // the 0 is the position where to insert [DU] which is 0 because you
        // want it at the beginning of the name.
        strins(nom,"[DU]",0,sizeof(nom));
        // Now that we inserted the clan tag into their name using strins, we
        // set their name with the clan tag.
        SetPlayerName(pid,nom);
    }
    return 1;
}