为什么monit抱怨无法读取pid文件？

我刚开始监视并且对 pid 文件有疑问：我已将以下内容添加到我的 /etc/monit/monitrc 中：

cat /etc/monit/monitrc
set daemon 30
set logfile /var/log/monit.log
set idfile /var/lib/monit/id
set statefile /var/lib/monit/state
set eventqueue
      basedir /var/lib/monit/events # set the base directory where events will be stored
      slots 100                     # optionally limit the queue size

check ping.sh
    with path "/path/to/ping.sh"
    every "44 * * * *"
    #if status != 0 then alert

我得到了以下内容/var/log/monit.log：

[UTC Sep 21 22:44:09] error    : Error reading pid from file '/path/to/ping.sh'
[UTC Sep 21 22:44:09] error    : 'ping.sh' process is not running
[UTC Sep 21 22:44:09] info     : 'ping.sh' trying to restart

尽管：

ls -l /path/to/ping.sh
-rwxrwxr-x 1 root root 1045 Sep 21 20:08 /path/to/ping.sh

在脚本内部，pid 存储在 /var/run/ping.pid 中：

#!/bin/bash
pidfile="/var/run/ping.pid"
# Get the pid of the currently running script
ps ax | grep $0 | grep $SHELL | awk '{print $1}'>$pidfile

pid 文件在脚本底部被删除：

rm $pid文件

为什么会出现错误：Error reading pid from file '/path/to/ping.sh'？

只是为了透明：我也在 [email protected] 邮件列表上发布了同样的问题，但它似乎不是很活跃。我将同步两个线程之间的任何回复！