python script deleting text immediately after writing it

Question

I'm working on script that checks on ping from several groups of devices and writing the devices ip to text file when the ping is successful

import os

ip_list=[]
data = open("data.txt",'w')

def pngtest():
    g=4
    s=2
    e=106
    while g < 11:
        for ip in range(s,e):
            ip_list.append('10.0.'+str(g)+'.'+str(ip))
        if g == 8:
            s=5
            e=122
        elif g == 9:
            s=2
            e=198
        elif g == 10:
            s=2
            e=254
        else:
            s=2
            e=106
        g +=1
pngtest()

for ip in ip_list:
    response = os.popen(f"ping {ip}").read()
    if "Received = 4" in response and 'TTL' in response:
        data.write(f"{ip}")
    else:
        print(f"ping {ip} failed")
data.close()

the problem is that it seems that the script does not writing any data to the text file. how do I fix this?

This if statement is never true in your code, probably: `if "Received = 4" in response and 'TTL' in response:` — oskros, May 31 '21 at 07:09
Are you sure the data is written, then deleted or could it be never written at all — mousetail, May 31 '21 at 07:13
try using 'a' mode instead of 'w' in the `open` function https://docs.python.org/3/library/functions.html#open — py_dude, May 31 '21 at 07:29

score 0 · Answer 1 · answered May 31 '21 at 07:13

0

try adding a timeout to ping

response = os.popen(f"ping -t 4 {ip}").read()

also print the response to see why you if didn't work.

print(f"ping {ip} failed response={response}")

answered May 31 '21 at 07:13

Yoav Glazner

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score 0 · Accepted Answer · answered May 31 '21 at 07:32

Try this. ping -c 1 will stop sending packets after single request.

for ip in ip_list:
  print("Checking" + IP)
  response = os.system("ping -c 1 " + ip + "> /dev/null" )
  if response == 0:
    data.write(f"{ip}")
  else:
    print(f"ping {ip} failed")

Maybe you should reframe your question. It is similar to this post.

python script deleting text immediately after writing it

2 Answers2