Run a program:

./waf --run <ns3-program> --command-template="%s <args>"
./waf --run=hello-simulator --command-template="gdb %s --args <args>"

Example for enabling logging:

export NS_LOG=UdpEchoClientApplication=level_all|prefix_func|prefix_time:UdpEchoServerApplication=level_all|prefix_func|prefix_time'
export 'NS_LOG=*=level_all|prefix_func|prefix_time'

Setting attributes at command line:

./waf --run "scratch/myfirst --PrintHelp"
./waf --run "scratch/myfirst --PrintAttributes=ns3::PointToPointNetDevice"
./waf --run "scratch/myfirst --ns3::PointToPointNetDevice::DataRate=5Mbps --ns3::PointToPointChannel::Delay=2ms --ns3::UdpEchoClient::MaxPackets=2"

Tcpdump:

tcpdump -nn -tt -r myfirst-0-0.pcap

Important classes: Node, Application, Channel (WifiChannel), NetDevice (WifiNetDevice)