Bash:If/Else语句一行 [英] Bash: If/Else statement in one line

问题描述

我正在尝试检查服务器上是否正在运行某个进程(假定它称为some_process).如果是，则回显1，否则回显0.

I am trying to check if a process (assume it is called some_process) is running on a server. If it is, then echo 1, otherwise echo 0.

这是我正在使用的命令，但仅部分起作用(下面有更多信息).请注意，我需要将脚本编写成一行.

This is the command that I am using but it only works partially (more info below). Note that I need to write the script in one line.

ps aux | grep some_proces[s] > /tmp/test.txt && if [ $? -eq 0 ]; then echo 1; else echo 0; fi

注意:some_proces[s]中的[s]是为了防止grep返回自身.

Note: The [s] in some_proces[s] is to prevent grep from returning itself.

如果some_process正在运行，则回显"1"，这很好.但是，如果some_process没有运行，则不会回显任何内容.

If some_process is running, then "1" gets echoed, which is fine. However, if some_process is not running, nothing gets echoed.

推荐答案

无需显式检查$?.只要做:

There is no need to explicitly check $?. Just do:

ps aux | grep some_proces[s] > /tmp/test.txt && echo 1 || echo 0 

请注意，这依赖于回声不会失败，这肯定不能得到保证.一种更可靠的书写方式是:

Note that this relies on echo not failing, which is certainly not guaranteed. A more reliable way to write this is:

if ps aux | grep some_proces[s] > /tmp/test.txt; then echo 1; else echo 0; fi

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