why pipeline content to command nc won't work?
apache-zookeeper, netcat, pipeline
Solution
Asked the same question in Zookeeper mail list, and got this:
Most probably you are using the wrong "nc" command.
Not kidding :P there are two different "nc" packages, and the syntax is different betweem then. In debian-like distros they are netcat-openbsd and netcat-traditional, but I ran into the same problems with netcat in CentOS (I can't remember the name of the packages, sorry) until I realized I was using it wrong.
--Tomas Nunez
I found that the nc on my server is nc.openbsd, after install nc.traditional,
`echo "stat" | nc.traditional 10.18.10.30 2181`
returns the expected result.
Problem
I try to get zookeeper stat from shell by using `nc`, call `nc localhost 2181` first, then type in: stat works. while `echo "stat" | nc localhost 2181` returns nothing. why?