【subprocess】专项

1. 快速查询手册

from subprocess import DEVNULL
import subprocess

# 会挂住等待执行完成，返回交互内容
# p1 = subprocess.Popen(['ping', '1.1.1.1'], stdout=subprocess.PIPE).communicate()[0]
# stdout, stderr = child.communicate()
# print(p1.decode('gbk'))


# 会挂住等待执行完成,返回执行状态 0成功，1失败
# ping = subprocess.call('ping 1.1.1.1',stdout=DEVNULL, stderr=subprocess.STDOUT,shell=False)
# print(ping)


# 会挂住等待执行完成,返回执行状态 0成功，1失败
# 和call等效
# ping = subprocess.Popen('ping 1.1.1.1',stdout=DEVNULL, stderr=subprocess.STDOUT,shell=False).wait()
# ping = subprocess.Popen('ping 1.1.1.1',stdout=subprocess.PIPE, stderr=subprocess.STDOUT,shell=False).wait() # 和上面一样
# print(ping)


# 不会挂住，返回subprocess.Popen对象【主程序退出后，子进程还在运行】
# ping = subprocess.Popen('ping 1.1.1.1',stdout=DEVNULL, stderr=subprocess.STDOUT,shell=False)
# print(ping)


# 会挂住等待执行完成，返回交互内容
ping = subprocess.Popen('ping 127.0.0.1',stdout=subprocess.PIPE, stderr=subprocess.STDOUT,shell=False)
# rst = ping.stdout.readlines() # 返回列表
# rst = ping.stdout.read()     # 返回字符串
rst = ping.stdout.read().decode('gbk')
print(rst)



# 会挂住等待执行完成，【实时】返回交互内容
ping = subprocess.Popen('ping 127.0.0.1',stdout=subprocess.PIPE, stderr=subprocess.STDOUT,shell=False)
for i in iter(ping.stdout.readline,b''):
    print(i.strip().decode('gbk'))




# 如果子进程还需要输入，则可以通过communicate()方法输入：
p = subprocess.Popen(['nslookup'], stdin=subprocess.PIPE, stdout=subprocess.PIPE, stderr=subprocess.PIPE)
output, err = p.communicate(b'set q=mx
python.org
exit
')
print(output.decode('utf-8'))
print('Exit code:', p.returncode)
上面的代码相当于在命令行执行命令nslookup，然后手动输入：
set q=mx
python.org
exit