名为print的简单python3程序-pid.py正在运行：cat print-pid.py

import os

from time import sleep

print('my pid is',os.getpid())

sleep(1000)

python3 print-pid.py的输出是：

^{pr2}$

用bash命令获取pid。在ps aux|grep 'python3 print-pid.py'|grep -v grep |awk '{print $2}'

5421

我想得到python3打印程序的pid-pid.py当它与python的sbupaccess模块一起运行时。在

这是我的尝试：import subprocess

cmd = "ps aux|grep 'python3 print-pid.py'|grep -v grep |awk '{print $2}'"

result = subprocess.run(cmd, stdout=subprocess.PIPE,shell=True)

print(result)

结果把我弄糊涂了。在

完成进程(args=“ps aux | grep”python3打印-pid.py“| grep-v grep | awk'{print$2}'”，返回代码=0，stdout=b“”

eturncode=0表示bash命令成功执行，为什么是stdout=b''而不是{}？在

感谢Allan在评论中的替换和测试建议。在

对于bash命令ps aux|grep 'python3'：import subprocess

cmd = "ps aux|grep 'python3'"

result = subprocess.run(cmd, stdout=subprocess.PIPE,shell=True)

print(result)

输出为：CompletedProcess(args="ps aux|grep 'python3'", returncode=0,

stdout=b'debian9 6569 0.0 0.2 31916 9376 pts/0 S+ 11:04 0:00 python3 print-p\ndebian9 6844 0.0 0.2 39860 11440 pts/2 S+ 11:13 0:00 python3\ndebian9 6929 0.0 0.0 16980 948 pts/2 S+ 11:17 0:00 grep python3\n')

但是对于bash命令ps aux|grep 'python3 print-pid.py'：import subprocess

cmd = "ps aux|grep 'python3 print-pid.py'"

result = subprocess.run(cmd, stdout=subprocess.PIPE,shell=True)

print(result)

输出：CompletedProcess(args="ps aux|grep 'python3 print-pid.py'", returncode=1, stdout=b'')

为什么不打印？在stdout=b'' instead of stdout=b'debian9 6569 0.0 0.2 31916 9376 pts/0 S+ 11:04 0:00 python3 print-p\n

debian9 6929 0.0 0.0 16980 948 pts/2 S+ 11:17 0:00 grep python3 print-pid.py\n'