On 12Jul2010 21:28, Jia Hu <huji...@gmail.com> wrote: | I have a problem about how to generate a specific.txt file. I use the | following code: | | #!/usr/bin/python | # OS: Ubuntu | import subprocess | fileName = open ('final.txt', 'a') | fileName.write ('%s %s %s \n' % (12,25,9))
String still in Python's buffer, not yet in the file. Add: fileName.flush() to ensure data in file before running echo. | desLrr = subprocess.Popen('echo "hello" >> final.txt ', shell=True) Command dispatched, but not yet waited for. So your Python program proceeds and writes to the file _before_ the echo command gets to run. Wait for desLrr to complete before proceeding. | fileName.seek(0,2) | fileName.write ('%s %s %s \n' % (85,25,12)) | fileName.close() And the rest is ok. Cheers, -- Cameron Simpson <c...@zip.com.au> DoD#743 http://www.cskk.ezoshosting.com/cs/ We tend to overestimate the short-term impact of technological change and underestimate its long-term impact. - Amara's Law -- http://mail.python.org/mailman/listinfo/python-list