Three kinds of python scripts call other ways, you know the other way?

1. Call python script python

#!/usr/local/bin/python3.7
import time
import os 

count = 0
str = ('python b.py')
result1 = os.system(str)
print(result1)
while True:
    count = count + 1
    if count == 8:
      print('this count is:',count) 
      break
    else:
      time.sleep(1)
      print('this count is:',count)   

print('Good Bye')

Another python script b.py as follows:

#!/usr/local/bin/python3.7
print('hello world')

operation result:

[python@master2 while]$ python a.py 
hello world
this count is: 1
this count is: 2
this count is: 3
this count is: 4
this count is: 5
this count is: 6
this count is: 7
this count is: 8
Good Bye

2.python call the shell method os.system ()

'''
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'''
#!/usr/local/bin/python3.7
import time
import os 

count = 0
n = os.system('sh b.sh')
while True:
    count = count + 1
    if count == 8:
      print('this count is:',count) 
      break
    else:
      time.sleep(1)
      print('this count is:',count)   

print('Good Bye')

shell script is as follows:

#!/bin/sh
echo "hello world"

operation result:

[python@master2 while]$ python a.py 
hello world
this count is: 1
this count is: 2
this count is: 3
this count is: 4
this count is: 5
this count is: 6
this count is: 7
this count is: 8
Good Bye

3.python call the shell method os.popen ()

'''
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'''
#!/usr/local/bin/python3.7
import time
import os 

count = 0
n = os.system('sh b.sh')
while True:
    count = count + 1
    if count == 8:
      print('this count is:',count) 
      break
    else:
      time.sleep(1)
      print('this count is:',count)   

print('Good Bye')

operation result:

[python@master2 while]$ python a.py 
<os._wrap_close object at 0x7f7f89377940>
['hello world\n']
this count is: 1
this count is: 2
this count is: 3
this count is: 4
this count is: 5
this count is: 6
this count is: 7
this count is: 8
Good Bye

os.system.popen () This method opens a conduit, the result is a file object of the connection pipe, the method of operating the same file object Open (), returns the result can be read from the file object. If successful, it will not return status code, if the execution fails, the error message is output to the stdout, and returns an empty string. Here the official also said subprocess module has achieved a more powerful subprocess.Popen () method.