how to install scapy on macOS Sierra

• scapy 1
• macOS 1
• Sierra 1

1. install homebrew.
2. install python with homebrew: brew install python. This is qutie important. Otherwise you will encounter other problems.
3. install scapy using pip: sudo pip install scapy.
4. install pypcap rather than pcapy, as the latter wouldn’t work: pip install pypcap
5. when encountered error like ‘import error: _io’, execute your script with sudo