Question

I’m running a small app on the command line, and I’m trying to watch the (http) network traffic it creates.

Is there some kind of wrapper program (like ‘time’, or ‘watch’) which can display all network traffic to and from my app? (Or at least, make a copy of it in a file)

Answer 1

Use tcpdump in command line or wireshark in desktop.

For example, to capture web traffic.
tcpdump -s0 -i any -wfile.pcap port 80
To watch it directly remove the -wfile.pcap

To read a previously saved file
tcpdump -r file.pcap

However for web traffic if you are interested of watching the http flow as it comes I like to use tcpflow -C port 80