#!/bin/bash

if [ $# -le  ]; then

    echo -e "usage  : \n\t$0 hostList REMOTE_CMD"

    echo -e "example: \n\t$0 hostList \"docker images | grep hive\""

    exit

fi

# concurrent number by default.

CON_NUM=

host_list="$1"

shift

remote_cmd="$@"

if [ ! -f $host_list ]; then

    echo "$host_list is not exist!"

    exit

fi

function your_cmd() {

    host=$

    #echo -e "---- cmd() start to : $host --"

    CMD="env TERM=xterm ssh $host \"$remote_cmd\" 2>/dev/null"

    eval ${CMD}

    ret=$?

    if [ $ret -ne  ];then

        echo -e "\t$host: cmd return retry $ret"

    fi

}

function concurrent()

{

    # ff_file which is opened by fd  will be really removed after script stopped

    mkfifo   ./fifo.$$ &&  exec <> ./fifo.$$ && rm -f ./fifo.$$

    # initial fifo: write $con_num line to $ff_file

    for ((i=; i<=$CON_NUM; i++)); do

        echo "init:$i" >&  # init fifo

    done

    for host in $(cat $host_list | grep -v "^#"); do

        read -u    # read from fifo to REPLY

        {

            #echo -e "\n-- current loop for: \"$host\" [ fifo id: \"$REPLY\" ]"

            your_cmd  "$host"

            echo -e "---- done: $host ----\n"

            echo "real:$host"  >& # write to $fifo

        } & # & to backgroud each process in {}

    done

    wait    # wait all con-current cmd in { } been running over

}