Minimal Busybox-compatible echo server (also good for Alpine)

MinimalEchoServer.md

Using nc (aka netcat) as a commonly available solution (but this syntax only tested for Alpine):

nc -lkp 8088 -e /bin/cat

nb:

• -l for listen
• -k to keep running for multiple calls (unavailable on busybox)
• -p for port parameter
• -e for program to execute (in the absence of a filename, cat echoes stdin to stdout)

To run with Docker:

docker run -d --rm -p 8088:8088 alpine nc -lkp 8088 -e /bin/cat 

To use, next run:

nc localhost 8088

This connects us in client mode. Type something, hit enter and observe the response.

Hello?
Hello?
You're a bot!
You're a bot!

Hit Ctrl-c to exit. With the "-l" flag you can repeat the sequence, without the "-k" flag the server nc would stop listening at this point.