check_status.sh

#! /bin/bash
# 
# File: check_status.sh
# Author: Kinch Zhang <kinch.zhang@gmail.com> with help from ChaoQian Xu <chaoranxu@gmail.com>
# Usage: $ check_status.sh [HOSTS ...]
#

function check()
{
    ip=`ping $1 | head -n 1| awk '{print $3}'`
    code=`curl -I $1 2>/dev/null| head -n 1| awk '{print $2}'`
    if [ -z "$code" ];then
        echo "[Error] couldn't connect to host $1."
        continue;
    fi

    if [ "$code" == 200 ];then
        echo "$1 $ip is OK."
    else
        echo "[Error] $1 $ip is DOWN (response code: $code)."
    fi
}

# display help 
if [ "$1" == "--help" ];then
    echo "usage: check_status.sh [HOSTS ...]"
    echo 
    echo -n "NOTE: if you invoke check_status.sh without any parameter,"
    echo "  it will read configuration from '~/server-list.txt'"
    exit;
fi

if [ -z "$1" ];then
    if [ -f "$HOME/server-list.txt" ];then
        # read config from file
        hosts=`cat ~/server-list.txt`
    else
        echo "[Error] file not exists: '~/server-list.txt'"
        hosts=''
    fi
else 
    hosts="$@"
fi

if [ -n "$hosts" ];then
    for host in $hosts
    do 
        check $host
    done
else
    echo "No hosts to check."
fi