Hi Bo,
I am trying to write a python script that will run the above
command and only print out the IP's that begin with 25. How do I
strip out all other text except for the IP's that begin with "25?"
I liked the suggestion by John Doe earlier that this is a pretty
good case for 'grep', but perhaps you want to do more than simply
see the results on the terminal.
So, you seem to want to be able to 'grep' for IPs that match a
particular prefix, 25.0.0.0/8. Do you, perchance work for
org-name: DINSA, Ministry of Defence [0]
or are you using 25.0.0.0/8 in a private network. If the latter,
are you sure you don't want to use one of the RFC 1918 networks?
Would it be best to send to a file first, then read the contents
of the file? Would I need to use regex?
Others have addressed some of this.
I know how to run the above command in python. I also know how to
send the output to a file and read the file; however I cannot
figure out how to strip all text out except for the IPs that begin
with "25."
Ok, so I can't help but observe that you are working with
IP-oriented data. While you can perform tests like:
ipstr.startswith('25') # -- yep, '250', '251', '253', '254', also
or similar tests by writing a regular expression and using one of
the heavier tools (re.findall, re.compile, re.match), I think that
merely helps you locate the text that you think is the IP address.
If you are asking is the IP within the 25.0.0.0/8 prefix, then you
probably want to use the ipaddr (Python 2.x from PyPI) or ipaddress
(Python 3.x stdlib) module to validate the IP and make sure that the
IP is in a prefix of interest.
I made one liberal change to the format of your data--I made it
tab-separated. If it is not tab-separated, then you can see which
line would probably need to have your regex line-splitter.
The below, is more general than finding every IP that starts with
'25.', because now you can "ipaddr-grep" for what you want.
#! /usr/bin/python
from __future__ import print_function
import sys
try: # -- Python2.x
import ipaddr as ipaddress
except ImportError: # -- Python3.x
import ipaddress
separator = '\t'
def ipaddr_grep(prefix, fin):
for line in fin:
line = line.strip()
if not line or line.startswith('#'):
continue
parts = line.strip().split(separator) # -- tab separated
ip = ipaddress.IPv4Address(parts[2])
if ip in prefix:
yield(line)
def ipaddr_grep_main(prefix, fnames):
prefix = ipaddress.IPv4Network(prefix)
while fnames:
fname = fnames.pop()
with open(fname) as fin:
for line in ipaddr_grep(prefix, fin):
print(line)
if __name__ == '__main__':
ipaddr_grep_main(sys.argv[1], sys.argv[2:])
I happen to be the sort of person who always wants to point out the
IP-related tools available in Python hence my reply to your post.
Happy trails and good luck,
-Martin
[0]
https://apps.db.ripe.net/search/query.html?searchtext=25.0.0.0/8&source=RIPE#resultsAnchor
--
Martin A. Brown
http://linux-ip.net/
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