Question

How do I strip comma from the end of a string? I tried

awk = subprocess.Popen([r"awk", "{print $10}"], stdin=subprocess.PIPE)
awk_stdin = awk.communicate(uptime_stdout)[0]
print awk_stdin
temp = awk_stdin
t = temp.strip(",")

also tried t = temp.rstrip(","), both don’t work.

---

This is the code:

uptime = subprocess.Popen([r"uptime"], stdout=subprocess.PIPE)
uptime_stdout = uptime.communicate()[0]
print uptime_stdout

awk = subprocess.Popen([r"awk", "{print $11}"], stdin=subprocess.PIPE)
awk_stdin = awk.communicate(uptime_stdout)[0]
print repr(awk_stdin)
temp = awk_stdin
tem = temp.rstrip("\n")
logfile = open('/usr/src/python/uptime.log', 'a')
logfile.write(tem + "\n")
logfile.close()

---

This is the output:

 17:07:32 up 27 days, 37 min,  2 users,  load average: 5.23, 5.09, 4.79

5.23,
None
Traceback (most recent call last):
  File "uptime.py", line 21, in ?
    tem = temp.rstrip("\n")
AttributeError: 'NoneType' object has no attribute 'rstrip'

Answer 1

When you say

awk = subprocess.Popen([r"awk", "{print $11}"], stdin=subprocess.PIPE)
awk_stdout = awk.communicate(uptime_stdout)[0]

then the output of the awk process is printed to stdout (e.g. a terminal).
awk_stdout is set to None. awk_stdout.rstrip('\n') raises an AttributeError because None has no attribute called rstrip.

When you say

awk = subprocess.Popen([r"awk", "{print $11}"], stdin=subprocess.PIPE,
                       stdout=subprocess.PIPE)
awk_stdout = awk.communicate(uptime_stdout)[0]

then nothing is printed to stdout (e.g. the terminal), and awk_stdout gets the output of the awk command as a string.