Use bash's tcp pseudo device for fun and profit

zk-4lw-from-bash.sh

#!/usr/bin/env bash

# We set up a file descriptor to redirect input/output from bash's tcp pseudodevice
# This allows us to, for example, call Zookeeper 4lws without needing netcat
# Works everywhere that bash works (proven on RHEL 7.x, AIX, MacOS bash 3.2)

ZKHOST="$1"
ZKPORT=2181
ZKCMD="$2"

if [ -z "$ZKCMD" ]; then
        echo "Usage $0 zkhost [wchp wchc wchs stat srvr srst ruok envi dump crst cons conf]"
        exit 1
fi

echo "Setting up file handle."
exec 3<>/dev/tcp/${ZKHOST}/${ZKPORT}

echo "Echo command to FH"

echo -e "${ZKCMD}" >&3

echo "Getting result..."
cat <&3