Hi Ravi,
./startManagedWebLogic.sh NonClusteredServer1
t3://172.21.32.122:1789 1>noncluster.log &
tail -f cluster1.log
here the complete functional description of the commands.
command 1
starts the server named " NonClusteredServer1" which is listening on 172.21.32.122:1789 in background mode [&] and the stdout is redirected to noncluster.log
command-2
you are tailing some log called cluster1.log - but where you have mentioned this log ???