python子进程模块subprocess详解与应用实例 之三
二、应用实例解析
2.1 subprocess模块的使用
1. subprocess.call
>>> subprocess.call(["ls", "-l"])
0
>>> subprocess.call("exit 1", shell=True)
1
2. 调用系统中cmd命令,显示命令执行的结果:
x=subprocess.check_output(["echo", "Hello World!"],shell=True)
print(x)
"Hello World!"
3. 在python中显示文件内容:
y=subprocess.check_output(["type", "app2.cpp"],shell=True)
print(y)
#include
using namespace std;
......
4. 查看ipconfig -all命令的输出,并将将输出保存到文件tmp.log中:
handle = open(r'd:\tmp.log','wt')
subprocess.Popen(['ipconfig','-all'], stdout=handle)
5. 查看网络设置ipconfig -all,保存到变量中
output = subprocess.Popen(['ipconfig','-all'], stdout=subprocess.PIPE,shell=True)
oc=output.communicate() #取出output中的字符串
#communicate() returns a tuple (stdoutdata, stderrdata).
print(oc[0]) #打印网络信息
Windows IP Configuration
Host Name . . . . .
6. 如果想频繁地和子线程通信,那么不能使用communicate();
因为communicate通信一次之后即关闭了管道.这时可以试试下面的方法:
p= subprocess.Popen(["wc"], stdin=subprocess.PIPE,stdout=subprocess.PIPE,shell=True)
p.stdin.write('your command')
p.stdin.flush()
#......do something
try:
#......do something
p.stdout.readline()
#......do something
except:
print('IOError')
#......do something more
p.stdin.write('your other command')
p.stdin.flush()
#......do something more
2.2 subprocess子进程和管道进行交互
其实在python中,和shell脚本,其他程序交互的方式有很多,比如:
os.system(cmd),os.system只是执行一个shell命令,不能输入、且无返回
os.open(cmd),可以交互,但是是一次性的,调用都少次都会创建和销毁多少次进程,性能太差
1. 一个简单的例子,调用ls命令,两者之间是没有交互的:
import subprocess
p = subprocess.Popen('ls')
2. 在程序中获取输出的例子:
import subprocess
p = subprocess.Popen('ls',stdout=subprocess.PIPE)
print p.stdout.readlines()
3. 有输入,有输出的例子,
父进程发送'say hi',子进程输出 test say hi,父进程获取输出并打印
#test1.py
import sys
line = sys.stdin.readline()
print 'test',line
#run.py
from subprocess import *
p =Popen('./test1.py',stdin=PIPE,stdout=PIPE)
p.stdin.write('say hi/n')
print p.stdout.readline()
#result
test say hi
4. 连续输入和输出的例子
# test.py
import sys
while True:
line = sys.stdin.readline()
if not line:break
sys.stdout.write(line)
sys.stdout.flush()
# run.py
import sys
from subprocess import *
proc = Popen('./test.py',stdin=PIPE,stdout=PIPE,shell=True)
for line in sys.stdin:
proc.stdin.write(line)
proc.stdin.flush()
output = proc.stdout.readline()
sys.stdout.write(output)
注意,run.py的flush和test.py中的flush,要记得清空缓冲区,否则程序得不到正确的输入和输出
2.3 python 实时获取子进程输出
1. 方法一
import subprocess
def main():
process1 = subprocess.Popen("python -u sub.py", shell=False, stdout = subprocess.PIPE, stderr=subprocess.STDOUT)
#print process1.communicate()[0]
while True:
line = process1.stdout.readline()
if not line:
break
print line
if __name__ == '__main__':
main()
2. 方法二:
import subprocess
import time
p = subprocess.Popen('ping 127.0.0.1 -n 10', stdout=subprocess.PIPE)
while p.poll() == None:
print p.stdout.readline()
time.sleep(1)
print p.stdout.read()
print 'returen code:', p.returncode
参考:
http://blog.csdn.net/junshao90/article/details/8215751
http://blog.csdn.net/b_h_l/article/details/10080171
http://blog.csdn.net/marising/article/details/6551692
from:http://blog.chinaunix.net/uid-26000296-id-4461555.html