报警端口状态改变

Question

#!/bin/bash
while :
do
if lsof -i :4444 | grep ESTABLISHED ;
then 
    paplay Alarm_Buzzer.ogg
fi
done

我正在尝试创建一个脚本来连续检查端口的状态。如果状态发生变化，脚本应该播放声音(一次)并继续检查更改。

港口有两个州：LISTEN和ESTABLISHED

Answer 1

澄清后；

获得当前端口state

• Continuously的

1. 启动脚本
2. 检查更改，如果是
   • 覆盖last，则播放声音(如果状态为changed

)

​

#!/bin/bash

# Port state at begin of script
# The awk part parses the string to only the last column containing;
# (LISTEN) OR (ESTABLISHED)
last=$(lsof -i :4444 | awk '{print $NF}')

# Continuously
while true; do

    # Get fresh port state
    state=$(lsof -i :4444 | awk '{print $NF}')

    # If it changed
    if [ "$state" != "$last" ]; then

        # Play sound
        paplay Alarm_Buzzer.ogg

        # Remember the new state
        last="$state"
    fi

    # No need to check so fast, sleep for a while (Thx @tomgalpin)
    sleep 1
done