Question

我正在尝试编写一个bash脚本，它将通过mac地址记录wifi连接的连接状态，但是我对代码的语法有些麻烦。

#!/bin/sh

client="E1:FA:41:23:00:AC"
logfile="/var/logs/wificonn.log"
timestamp=$(date +"%Y%d%m %T")
assoclist=$(wl assoclist | grep $client)
loglast=$(tail -n 1 $logfile | grep $client Not Connected)
notconnmsg="$timestamp $client Not Connected"
connmsg="$timestamp $client Connected"

if [ ! -f $logfile ]; then
    touch $logfile
fi

if [ -z $assoclist  ]; then # Client is not connected
  if [ -n $loglast ]; then # Last log is connected show not connected message
    echo $notconnmsg
    echo $notconnmsg >> $logfile
  fi  
else # Client is connected
  if [ -z $loglast ]; then  # Last log is not connected show connected message
    echo $connmsg
    echo $connmsg >> $logfile
  fi  
fi

这将每隔60秒作为一个cron作业运行，并且只有在相反的情况下才显示/记录已连接或未连接的事件。我试图通过检查最后一个日志条目来实现这一点。例如，如果上次日志未连接且现已连接，请登录到文件。这就是问题所在。

感谢

Answer 1

我改变了代码并获得了这个有效的解决方案以防任何人想要使用它

#!/bin/sh

client="XX:XX:XX:XX:XX:XX"
logfile="/var/log/wifilog-$(date +"%m%d")-$client.log"
assoclist=$(wl assoclist | grep $client)
notconnmsg="$(date +"%T") Disconnected"
connmsg="$(date +"%T") Connected"

if [ ! -f $logfile ]; then
    echo $notconnmsg > $logfile
fi

if [ -z $assoclist  ]; then # Client is not connected
  echo $(tail -n 1 $logfile) - $notconnmsg
  if [ -z $(tail -n 1 $logfile | grep "Disconnected") ]; then # Last log is connected show not connected message
    echo $notconnmsg >> $logfile    
  fi  
else # Client is connected
  echo $(tail -n 1 $logfile) - $connmsg
  if [ -z $(tail -n 1 $logfile | grep "Connected") ]; then  # Last log is not connected show connected message
    echo $connmsg >> $logfile    
  fi   
fi

Answer 2

if [ -n $loglast ]; then

尝试用双引号括起$loglast：

if [ -n "$loglast" ]; then

当$loglast为空时，bash会看到if [ -n ]。你没有评估一个空参数，你什么也没有评估。您可以尝试以下方法来查看差异：

$ loglast=""
$ if [ -n "$loglast" ]; then echo 'yep'; fi
# <no output>
$ if [ -n $loglast ]; then echo 'yep'; fi
# yep

跟踪连接的wifi设备bash脚本

2 个答案: