sys.stdout.write或print覆盖subprocess.call输出

我在全球村 2012-06-20 10:56:04

写了个小程序，但是在输出到文本时出现了问题，请大家帮忙解答下，先谢了哈！

程序：
1 import subprocess
2
3
4 import sys
5 sys.stdout = open("record.txt","w")
6
7 fp = open("record.txt","w")
8 def func1():
9 uname = "uname"
10 uname_arg = "-a"
11 tmp_str = "the system information is : " + "/n"
12 sys.stdout.write( tmp_str ) ######此处改为print函数输出，问题也一样
13 subprocess.call([uname, uname_arg],stdout=fp)
14
15 def func2():
16 diskspace = "df"
17 diskspace_arg = "-h"
18 tmp_str = "the disk information is : " + "/n"
19 sys.stdout.write( tmp_str )
20 subprocess.call([diskspace,diskspace_arg],stdout=fp)
21 def main():
22 func1()
23 func2()
24
25 if __name__ == "__main__":
26 main()
~
~
输出为：
the system information is : /nthe disk information is : /nv 28 19:23:11 UTC 2011 i686 G NU/Linux
2 Filesystem Size Used Avail Use% Mounted on
3 /dev/sda5 19G 6.3G 12G 35% /
4 none 997M 212K 996M 1% /dev
5 none 1002M 24K 1002M 1% /dev/shm
6 none 1002M 76K 1002M 1% /var/run
7 none 1002M 0 1002M 0% /var/lock
8 /dev/sda1 118M 44M 68M 40% /boot
9 /dev/sda7 98G 1.5G 92G 2% /home

请大家注意以上输出中标明的红色部分，出现 sys.stdout.write或print覆盖subprocess.call输出，我把它的位置换到其它地方，仍然不能解决，为何先执行后者，再执行前者呢？
求解答

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我在全球村 2012-06-21

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bugs2k 2012-06-20

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zhu@ubuntu:~/python$ ./df.py
The system information is:
Linux ubuntu 3.2.0-25-generic #40-Ubuntu SMP Wed May 23 20:30:51 UTC 2012 x86_64 x86_64 x86_64 GNU/Linux
The disk information is:
Filesystem Size Used Avail Use% Mounted on
/dev/loop0 29G 17G 11G 62% /
udev 989M 4.0K 989M 1% /dev
tmpfs 399M 836K 398M 1% /run
none 5.0M 0 5.0M 0% /run/lock
none 997M 156K 997M 1% /run/shm
/dev/sdb1 98G 31G 68G 31% /host

zhu@ubuntu:~/python$ python -V
Python 2.7.3
zhu@ubuntu:~/python$

bugs2k 2012-06-20

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#!/usr/bin/env python



import subprocess

import sys



def fun1():

    args = ['uname', '-a']

    print "The system information is:"

    #sys.stdout.flush()

    subprocess.call(args)



def fun2():

    args = ['df', '-h']

    print "The disk information is:"

    #sys.stdout.flush()

    subprocess.call(args)



def main():

    fun1()

    fun2()



if __name__ == '__main__':



    main()

bugs2k 2012-06-20

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#!/usr/bin/env python



import subprocess



def fun1():

    args = ['uname', '-a']

    subprocess.call(args)



def fun2():

    args = ['df', '-h']

    subprocess.call(args)



def main():

    fun1()

    fun2()



if __name__ == '__main__':



    main()

我在全球村 2012-06-20

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还有就是我如何修改才能让提示信息一一对应呢？

我在全球村 2012-06-20

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file.flush()

Flush the internal buffer, like stdio‘s fflush(). This may be a no-op on some file-like objects.

Note

flush() does not necessarily write the file’s data to disk. Use flush() followed by os.fsync() to ensure this behavior.

我在全球村 2012-06-20

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现在的确把问题解决了，不过能有文字解释下或链接个解释log.flush()处理缓存的过程就更好了，谢谢！

bugs2k 2012-06-20

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#!/usr/bin/env python



import subprocess

import sys



log = open('dfuname.txt', 'w')



def fun1():

    args = ['uname', '-a']

    log.write("The system information is:\n")

    log.flush()

    subprocess.call(args, stdout=log)



def fun2():

    args = ['df', '-h']

    log.write("The disk information is:\n")

    log.flush()

    subprocess.call(args, stdout=log)



def main():

    fun1()

    fun2()



if __name__ == '__main__':



    main()

zhu@ubuntu:~/python$ ./df.py
zhu@ubuntu:~/python$ cat dfuname.txt
The system information is:
Linux ubuntu 3.2.0-25-generic #40-Ubuntu SMP Wed May 23 20:30:51 UTC 2012 x86_64 x86_64 x86_64 GNU/Linux
The disk information is:
Filesystem Size Used Avail Use% Mounted on
/dev/loop0 29G 17G 11G 61% /
udev 989M 4.0K 989M 1% /dev
tmpfs 399M 836K 398M 1% /run
none 5.0M 0 5.0M 0% /run/lock
none 997M 156K 997M 1% /run/shm
/dev/sdb1 98G 31G 68G 31% /host
zhu@ubuntu:~/python$

我在全球村 2012-06-20