// This should be in the Programming forum IMHO.
Can someone post a simple bash script listening on a TCP port?
"GET", OK, "listen", no. At least I can't in pure shell. I know there's some toolkits to do server-client things in Bash but they're *way ancient*: look for Socketd (firstname.lastname@example.org) or Socket (email@example.com). For both this and the question below explaining why you need it would be cool. Verbosity may lead to us giving suggestions or solutions that better match your task or situation.
How can I read tcp packet in bash?
Bash has no concept of "packets" or how to "read" them.
You want to resort to using a legitimate sniffer.