Script hangs, no errors

[Tester_V]

I got 3 scripts.
1st script scans subnets and prints out Active and not Active IPs.
2d script opens file with Active IPs and finds corresponding Active Hosts names.
3d script opens file with the Active Hosts names and pulls out some stuff from it.

When I ran each script separately, I have no errors or problems but when put all three of them in to one script it hangs on the second script with no errors and never starts third part of the script.
############################################################################################
[sub]import socket
import sys

pfile = open('C:/Python_TEST/IP_Scan/Lists/IP_Active1.txt')
h_active = open("C:/Python_TEST/IP_Scan/Lists/IP_Host_Active.txt","w")

sys.stdout = h_active

while True:
IP = pfile.readline()
try:
host = socket.gethostbyaddr(IP.rstrip())
#(IP.rstrip())
#host = socket.gethostbyaddr(IP.rstrip())
print (IP,file=h_active)
print(IP,host)
except Exception as e:
print(IP,"NULL")

pfile.close()
h_active.close()[/sub]

 

[mintjulep]

While True:

Never ends.

 

[Tester_V]

Thank you for the reply.
I just started learning Python I found this snippet and really do not fully understand.
I understand "try:" and "except:" will allow the code run even if an error,I'm confused about "while True:"
Do you know how to fix this?
Thank you.

 

[mikrom]

Do you know how to fix this?

There are several ways how to read a text file in python: for example look here:

https://cmdlinetips.com/2011/08/three-ways-to-read-a-text-file-line-by-line-in-python/

 

[Tester_V]

Finally I got it.
Wanted to share with you good people this simple snippet.
I just added "if" loop that will break at the EOF.

[sup]pflie = open('C:/Scripts/somefile_toread.txt')
h_active = open("C:/Scripts/somefile_towrite.txt","w")

sys.stdout = h_active

while True:
IP = pflie.readline()
if (""==IP) :
print ("EOF")
break
else :
try:
host = socket.gethostbyaddr(IP.rstrip())
print(IP,host)

h_active.write("IP,host")
except Exception as e:

print(IP,Exception)

pflie.close()
h_active.close()[/sup]