Question

大家好我想为我的服务器编写一个wol脚本代码。树莓派在每次启动时都会执行。

我猜它是一个语法错误，但我现在不是解决方案，所以我问你。我在第5行收到错误，但不知道如何纠正错误。

#!/bin/bash

nas=[ping -c 1 192.192.168.222.5 &> /dev/null ]

until [ $nas = "1" ];do
python wol.py
sleep 2
nas=[ping -c 1 192.192.168.222.5 &> /dev/null ]
done

wol.py是发送wol包的marc balmar的脚本

#!/usr/bin/env python
#coding: utf8

# Wake-On-LAN
#
# Copyright (C) 2002 by Micro Systems Marc Balmer
# Written by Marc Balmer, marc@msys.ch, http://www.msys.ch/
# Modified by saarnu for nerdoskop.wordpress.com
# This code is free software under the GPL

import struct, socket, time, os

def WakeOnLan(ethernet_address):

  # Construct a six-byte hardware address

  addr_byte = ethernet_address.split(':')
  hw_addr = struct.pack('BBBBBB', int(addr_byte[0], 16),
    int(addr_byte[1], 16),
    int(addr_byte[2], 16),
    int(addr_byte[3], 16),
    int(addr_byte[4], 16),
    int(addr_byte[5], 16))

  # Build the Wake-On-LAN "Magic Packet"...

  msg = '\xff' * 6 + hw_addr * 16

  # ...and send it to the broadcast address using UDP
  time.sleep(5)
  s = socket.socket(socket.AF_INET, socket.SOCK_DGRAM)
  s.setsockopt(socket.SOL_SOCKET, socket.SO_BROADCAST, 1)
  s.sendto(msg, ('<broadcast>', 9))
  s.close()

WakeOnLan('C8:60:00:6D:CF:54') # MAC-Adresse der DiskStation

我在powershell中编写了一个类似的代码，它实际上要复制它或者将它翻译成bash要容易得多。

$NAS = test-connection -count 1 -quiet 192.168.222.5
if ($NAS -like "False"){
do
{
$Mac = "C8:60:00:6D:CF:54"
$MacByteArray = $Mac -split "[:-]" | ForEach-Object { [Byte] "0x$_"}
[Byte[]] $MagicPacket = (,0xFF * 6) + ($MacByteArray  * 16)
$UdpClient = New-Object System.Net.Sockets.UdpClient
$UdpClient.Connect(([System.Net.IPAddress]::Broadcast),7)
$UdpClient.Send($MagicPacket,$MagicPacket.Length)
$UdpClient.Close()
Start-Sleep -s 5
$NAS = test-connection -count 1 -quiet 192.168.222.5
}
until
(
$NAS -like "True"
)
}

Answer 1

首先，使用http://www.shellcheck.net修复脚本中的语法问题。

您的命令替换语法错误，使用该修复并直接在ping

中使用until-loop的退出代码

until ping -c 1 192.192.168.222.5 &> /dev/null
do
    python wol.py
    sleep 2
done

应该解决你的问题。 man的{{1}}页说

如果ping根本没有收到任何回复数据包，它将以代码1退出。如果指定了数据包计数和截止时间，并且在截止日期到达之前收到的数据包数量少于它，则它也将退出代码1.在其他错误上，它以代码2退出。否则它以代码0退出。这使得可以使用退出代码来查看主机是否存活。

Answer 2

嘿，你的bash脚本中有一些错误，而不只是一个。

#!/bin/bash

# This is a silent ping. The output is redirected to /dev/null. The only visible
# change in user-land will be the exit code, available as $?.
# The exit code "0" means success, the exit code "1" means some error.

ping -c 1 192.192.168.222.5 &> /dev/null

# You need double round parenthesis here to evaluate a comparison.
# Also a comparison, as almost everywhere in programming, is "==" instead of "=".
until (( $? == "0" ));
    do
    python wol.py
    sleep 2
    # There is the silent ping again. Updating $?.
    ping -c 1 192.192.168.222.5 &> /dev/null
done

有关退出代码，请参阅： Exit Shell Script Based on Process Exit Code

对于不同的括号/括号，请通过man bash，How to use double or single brackets, parentheses, curly braces或https://stackoverflow.com/a/9666169/7236811查看真正优秀的bash手册。

bash脚本可能语法错误，不确定尝试直到循环

2 个答案: