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"
