if(!strcmp(cmdtext,"/minigun",true))
{
    new string[128], name[24];
    GetPlayerName(playerid, name, sizeof name); // This will get the name of the player
    GivePlayerWeapon(playerid, 38, 9999); //Give playerid minigun with 9999 ammo
    SetPlayerInterior(playerid, 0); //Set playerid Interioir 0
    SetPlayerPos(playerid, -2299.4580,1864.7584,15.5630); //Set playerid to spawn location
    format(string, sizeof string, "%s joined the minigun lobby!", name); // %s holds the variable name, which is the playername 
    SendClientMessageToAll(-1, string); // This will send the string which you formatted above
    return 1;
}