linux脚本与netcat在x小时后停止工作

发布时间：2020-12-13 19:40:53 所属栏目：Linux 来源：网络整理

导读：我必须要脚本： #!/bin/bashnetcat -lk -p 12345 | while read linedo match=$(echo $line | grep -c 'Keep-Alive') if [ $match -eq 1 ]; then [start a command] fidone 和 #!/bin/bashnetcat -lk -p 12346 | while read linedo match=$(echo $line | grep

我必须要脚本：

#!/bin/bash

netcat -lk -p 12345 | while read line
do
    match=$(echo $line | grep -c 'Keep-Alive')
    if [ $match -eq 1 ]; then
        [start a command]
    fi
done

和

#!/bin/bash

netcat -lk -p 12346 | while read line
do
    match=$(echo $line | grep -c 'Keep-Alive')
    if [ $match -eq 1 ]; then
        [start a command]
    fi
done

我把这两个脚本放在’/etc/init.d/’

当我重新启动我的Linux机器(RasbPi)时,这两个脚本都可以正常工作.

我已经尝试了20次,他们继续工作正常.

但大约12个小时后,整个系统停止工作.我已经注册了一些登录,但似乎这些脚本不再起作用了.但是当我

ps aux

我可以看到脚本仍在运行：

root      1686  0.0  0.2   2740  1184 ?        S    Aug12   0:00 /bin/bash /etc/init.d/script1.sh start
root      1689  0.0  0.1   2268   512 ?        S    Aug12   0:00 netcat -lk 12345
root      1690  0.0  0.1   2744   784 ?        S    Aug12   0:00 /bin/bash /etc/init.d/script1.sh start
root      1691  0.0  0.2   2740  1184 ?        S    Aug12   0:00 /bin/bash /etc/init.d/script2.sh start
root      1694  0.0  0.1   2268   512 ?        S    Aug12   0:00 netcat -lk 12346
root      1695  0.0  0.1   2744   784 ?        S    Aug12   0:00 /bin/bash /etc/init.d/script2.sh start

重新启动后,他们再次开始工作…但这是一个罪,定期重新启动一台Linux机器…

我已经插入了一些登录,这是结果;

Listening on [0.0.0.0] (family 0,port 12345)
[2013-08-14 11:55:00] Starting loop.
[2013-08-14 11:55:00] Starting netcat.
netcat: Address already in use
[2013-08-14 11:55:00] Netcat has stopped or crashed.
[2013-08-14 11:49:52] Starting loop.
[2013-08-14 11:49:52] Starting netcat.
Listening on [0.0.0.0] (family 0,port 12345)
Connection from [16.8.94.19] port 12345 [tcp/*] accepted (family 2,sport 6333)
Connection closed,listening again.
Connection from [16.8.94.19] port 12345 [tcp/*] accepted (family 2,sport 6334)
[2013-08-14 12:40:02] Starting loop.
[2013-08-14 12:40:02] Starting netcat.
netcat: Address already in use
[2013-08-14 12:40:02] Netcat has stopped or crashed.
[2013-08-14 12:17:16] Starting loop.
[2013-08-14 12:17:16] Starting netcat.
Listening on [0.0.0.0] (family 0,sport 6387)
Connection closed,sport 6388)
[2013-08-14 13:10:08] Starting loop.
[2013-08-14 13:10:08] Starting netcat.
netcat: Address already in use
[2013-08-14 13:10:08] Netcat has stopped or crashed.
[2013-08-14 12:17:16] Starting loop.
[2013-08-14 12:17:16] Starting netcat.
Listening on [0.0.0.0] (family 0,sport 6167)
Connection closed,sport 6168)

谢谢

解决方法

如果您的命令(包括netcat)都没有读取stdin的输入,您可以完全使其独立于终端运行.有时,依赖于终端的后台进程会在后台读取输入时暂停(S).实际上,由于你运行一个守护进程,你应该确保没有一个命令读取它的输入(终端).

#!/bin/bash

set +o monitor # Make sure job control is disabled.

(
    : # Make sure the shell runs a subshell.
    exec netcat -lk -p 12345 | while read line  ## Use exec to overwrite the subshell.
    do
        match=$(echo $line | grep -c 'Keep-Alive')
        if [ $match -eq 1 ]; then
            [start a command]
        fi
    done
) <&- >&- 2>&- </dev/null &>/dev/null &

TASKPID=$!
sleep 1s ## Let the task initialize a bit before we disown it.
disown "$TASKPID"

而且我想我们可以再试一次记录：

set +o monitor

(
    echo "[$(date "+%F %T")] Starting loop with PID $BASHPID."

    for (( ;; ))
    do
        echo "[$(date "+%F %T")] Starting netcat."

        netcat -vv -lk -p 12345 | while read line
        do
            match=$(echo "$line" | grep -c 'Keep-Alive')
            if [ "$match" -eq 1 ]; then
                [start a command]
            fi
        done

        echo "[$(date "+%F %T")] Netcat has stopped or crashed."

        sleep 4s
    done
) <&- >&- 2>&- </dev/null >> "/var/log/something.log" 2>&1 &

TASKPID=$!
sleep 1s
disown "$TASKPID"

（编辑：李大同）

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