I'd love if there was a single command line tool for packet sniffing a single command in Linux. something like sniff dumpfile command so that you could just run the command you want to packet sniff in the terminal and get a dump of the packets somewhere else.
I'd like to dump / save / see only the network traffic of the single command that I enter, not all the TCP traffic on my single network interface. So if I was logged into my computer and had IRC running in the background, and I did sniff somefile wget http://www.google.com, I'd want to see all the network traffic that the wget command did to download http://www.google.com. I don't want 'somefile' to have the IRC network traffic confusing things.
There are lots of linux/unix commands that accept a different command and do something different. From sudo (run as superuser), nice change nice level, trickle (limit the bandwidth of a command)
Best Answer
There isn't any that I know of, but it theoretically shouldn't be hard to get something similar. Strace can be used to intercept networking syscalls.
This will give you information about the data sent between the kernel and the process. The output of strace isn't exactly what you'd want. However, strace uses the ptrace syscall to intercept system calls. It might be possible to write a program to output the data a little more usefully.
Alternatively, you can also intercept the nice useful socket, bind and listen syscalls. It might be possible to write a small program that used ptrace on these calls and libpcap to dynamically change the capture filter every time a new socket is opened.