[CutX]

you'd have to loop trough all vehicles

pawn Код:

YCMD:repairall(playerid,params[],help)
{
    if(help) return SendClientMessage(playerid,-1,"/repairall is used to repair every single vehicle on the server.");
    //maybe do some admin-condition here
    for(new i=0; i<MAX_VEHICLES; i++)
        RepairVehicle(i);
        
    SendClientMessageToAll(-1,"All vehicles have been repaired by an admin!");
}

instead of MAX_VEHICLES
you could also use

pawn Код:

stock GetMaxVehicles()
{
    new iCount;
    for(new i = 1; i < MAX_VEHICLES; ++i)
        if(GetVehicleModel(i)) iCount++;

    return iCount;
}