Wireshark

Wireshark has a GUI both on Windows and Linux. It is convenient to capture and decode the network packets, esp. for those application protocols. It also support a CLI interface named tshark. Here are some examples.

$ sudo tshark -i bond0 -f 'tcp port 3306'                 # Capture tcp port=3306, that is MySQL. -V output more.
$ sudo tshark -i bond0 -f 'tcp port 3306' -w tshark.txt   # And write the output to file tshark.txt.
$ sudo tshark -r tshark.txt -d tcp.port==3306,mysql -V    # Decode the file as MySQL's protocol.