Question

有人可以在我做的时候告诉我＆＃34; meta refresh＆＃34;如下所示，那还会再次运行bash program-run-tmp-directory3.sh &> stdout.out &吗？或者，只有浏览器会刷新，apache还活着吗？

＆＃34; PID ＆＃34;是＆＃34;进程ID＆＃34;该程序在后台运行。

如果以下代码也重新运行程序bash program-run-tmp-directory3.sh &> stdout.out &。请让我知道如何避免它？

#!/bin/sh
echo "Content-type: text/html"
echo ""
bash program-run-tmp-directory3.sh &> stdout.out &
pid=$!

if [[ `ps -p $pid | wc -l` -gt 1 ]]
then
    output="Program is running. Running time depends on the number of alternatively spliced proteins the submitted gene has. Results will be displayed here."
    echo "<html>"
    echo "<head>"
    echo "<meta http-equiv=\"refresh\" content=\"10\"/>"
    echo "</head>"
    echo "<body>"
    echo "<table width=\"750\" border=\"0\" cellspacing=\"0\" cellpadding=\"0\">"
    echo "<tr><td><img src=\"../../images/calc.gif\" align=\"absmiddle\"> <strong> $output </strong></td></tr>"
    echo "</table>"
    echo "</body>"
    echo "</html>"
fi

感谢。

Answer 1

此时，您的问题似乎是如何在bash脚本中检测到另一个脚本正在运行并避免重新生成它。一个通常足够好的快速而简单的方法是grep脚本命令行的ps输出。这有点复杂，因为根据您用于ps的选项，它还可能显示grep进程命令行，显然还包括脚本的命令行作为grep模式的一部分。解决这个问题的方法之一是here。所有这些解释都比实际脚本长。

还有一点需要注意。只是想确保您了解bash构建$!的含义：

($!) Expands to the process ID of the job most recently placed into
the background, whether executed as an asynchronous command or using
the bg builtin (see Job Control Builtins).

所以，这只会引用你的CGI脚本的当前执行所知道的事情。当您的浏览器决定再次刷新时，会向您的服务器发送另一个HTTP GET，这会再次产生您的CGI脚本，此时$!仅引用最近由该实例你的剧本。

如果我想知道你正在尝试做什么，你可能会想要这样的事情（未经测试）：

#!/bin/sh echo "Content-type: text/html" echo "" # if other script not already running if ! ps aux | grep "[b]ash.*program-run-tmp-directory3.sh" then bash program-run-tmp-directory3.sh &> stdout.out & # I'm superstitious; let's give it a moment to start sleep 1 fi if ps aux | grep "[b]ash.*program-run-tmp-directory3.sh" then output="Program is running. Running time depends on the number of alternatively spliced proteins the submitted gene has. Results will be displayed here." echo "<html>" echo "<head>" echo "<meta http-equiv=\"refresh\" content=\"10\"/>" echo "</head>" echo "<body>" echo "<table width=\"750\" border=\"0\" cellspacing=\"0\" cellpadding=\"0\">" echo "<tr><td><img src=\"../../images/calc.gif\" align=\"absmiddle\"> <strong> $output </strong></td></tr>" echo "</table>" echo "</body>" echo "</html>" else : # ... some useful error output composed as HTML fi

元刷新（仅刷新浏览器）

1 个答案: