如果正在运行，如何检入 bash 脚本，如果正在运行则退出
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原文地址: http://stackoverflow.com/questions/927091/
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How to check in a bash script if something is running and exit if it is
提问by Ryan Detzel
I have a script that runs every 15 minutes but sometimes if the box is busy it hangs and the next process will start before the first one is finished creating a snowball effect. How can I add a couple lines to the bash script to check to see if something is running first before starting?
我有一个脚本每 15 分钟运行一次，但有时如果盒子很忙，它会挂起，下一个进程将在第一个进程完成创建滚雪球效果之前开始。如何在 bash 脚本中添加几行以检查是否在开始之前先运行了某些内容？
采纳答案by allaryin
In lieu of pidfiles, as long as your script has a uniquely identifiable name you can do something like this:
代替 pidfiles，只要您的脚本具有唯一可识别的名称，您就可以执行以下操作：
#!/bin/bash
COMMAND=if pidof -x vim > /dev/null
then
echo "Vim already running"
exit 1
fi
# exit if I am already running
RUNNING=`ps --no-headers -C${COMMAND} | wc -l`
if [ ${RUNNING} -gt 1 ]; then
echo "Previous ${COMMAND} is still running."
exit 1
fi
... rest of script ...
回答by rodion
You can use pidof -xif you know the process name, or kill -0if you know the PID.
pidof -x如果您知道进程名称或kill -0PID ，则可以使用。
Example:
例子：
if [ -f yourapp.lock ]; then
echo "The process is already launched, please wait..."
fi
回答by Boris Guéry
Why don't set a lock file ?
为什么不设置锁定文件？
Something like
就像是
yourapp.lock
yourapp.lock
Just remove it when you process is finished, and check for it before to launch it.
只需在处理完成后将其删除，并在启动之前检查它。
It could be done using
可以使用
lockfile=~/myproc.lock
minutes=60
if [ -f "$lockfile" ]
then
filestr=`find $lockfile -mmin +$minutes -print`
if [ "$filestr" = "" ]; then
echo "Lockfile is not older than $minutes minutes! Another echo "Removing lock $lockfile ..."
rm $lockfile
running. Exiting ..."
exit 1
else
echo "Lockfile is older than $minutes minutes, ignoring it!"
rm $lockfile
fi
fi
echo "Creating lockfile $lockfile"
touch $lockfile
回答by A1g0r1thm
This is how I do it in one of my cron jobs
这就是我在一项 cron 工作中的做法
pgrep -f yourscript >/dev/null && exit
and delete the lock file at the end of the script
并删除脚本末尾的锁定文件
echo "Starting process..."
run-process > $OUTPUT &
pid=$!
echo "Process started pid=$pid"
while true; do
kill -0 $pid 2> /dev/null || { echo "Process exit detected"; break; }
sleep 1
done
echo "Done."
回答by chaos
echo $$ > /tmp/lock.$$
if ! ln /tmp/lock.$$ /tmp/lock ; then
echo "previous backup in process"
rm /tmp/lock.$$
exit
fi
回答by lhunath
For a method that does not suffer from parsing bugs and race conditions, check out:
对于不受解析错误和竞争条件影响的方法，请查看：
回答by Ruslan
I had recently the same question and found from above that kill -0 is best for my case:
我最近遇到了同样的问题，从上面发现 kill -0 最适合我的情况：
FILE="/tmp/my_file"
if [ -f "$FILE" ]; then
echo "Still running"
exit
fi
trap EXIT "rm -f $FILE"
touch $FILE
...script here...
回答by Paul Tomblin
To expand on what @bgy says, the safe atomicway to create a lock file if it doesn't exist yet, and fail if it doesn't, is to create a temp file, then hard link it to the standard lock file. This protects against another process creating the file in between you testing for it and you creating it.
为了扩展@bgy 所说的内容，如果锁文件尚不存在，则创建锁文件的安全原子方法是创建临时文件，然后将其硬链接到标准锁文件。这可以防止在您测试文件和创建文件之间创建文件的另一个进程。
Here is the lock file code from my hourly backup script:
这是我的每小时备份脚本中的锁定文件代码：
##代码##Don't forget to delete both the lock file and the temp file when you're done, even if you exit early through an error.
完成后不要忘记删除锁定文件和临时文件，即使您因错误提前退出。
回答by 0x6adb015
Use this script:
使用这个脚本：
##代码##This script will create a file and remove it on exit.
此脚本将创建一个文件并在退出时将其删除。
