如何使用 grep 捕获字段发出命令？

Question

I'm trying to capture a process that runs and make an strace of it in one line:我正在尝试捕获一个正在运行的进程并在一行中对其进行跟踪：

I managed to capture only the one that i want with this command我设法用这个命令只捕获了我想要的那个

ps -ef | grep "[0-9].*[0-9] /usr/bin/python3 /home/pi/readcard.py"

outputs this:输出这个：

root       676   668 99 11:00 ?        00:34:21 /usr/bin/python3 /home/pi/readcard.py

Now I'm trying to capture the process pid with this regex and use it to make another command:现在我正在尝试使用此正则表达式捕获进程 pid 并使用它来创建另一个命令：

ps -ef | grep "([0-9]+).*[0-9] /usr/bin/python3 /home/pi/readcard.py"

How I could make to run something like this?我怎么能运行这样的东西？

sudo strace -f -p{captured_field} -s9999 -e write

Answer 1

Use awk for only showing the second column:使用awk仅显示第二列：

ps -ef | grep "([0-9]+).*[0-9] /usr/bin/python3 /home/pi/readcard.py" | awk '{print $2}'

This, you can use it as an input for another command, by embedding it into $(...) , as follows:这样，您可以通过将其嵌入到$(...)中，将其用作另一个命令的输入，如下所示：

sudo strace -f -p{$(ps -ef | grep "([0-9]+).*[0-9] /usr/bin/python3 /home/pi/readcard.py" | awk '{print $2}')} -s9999 -e write

Good luck祝你好运