Bash Script: count unique lines in file - bash

Question

Situation:
I have a large file (millions of lines) containing IP addresses and ports from a several hour network capture, one ip/port per line. Lines are of this format:
ip.ad.dre.ss[:port]
Desired result:
There is an entry for each packet I received while logging, so there are a lot of duplicate addresses. I'd like to be able to run this through a shell script of some sort which will be able to reduce it to lines of the format
ip.ad.dre.ss[:port] count
where count is the number of occurrences of that specific address (and port). No special work has to be done, treat different ports as different addresses.
So far, I'm using this command to scrape all of the ip addresses from the log file:
grep -o -E [0-9]+\.[0-9]+\.[0-9]+\.[0-9]+(:[0-9]+)? ip_traffic-1.log > ips.txt
From that, I can use a fairly simple regex to scrape out all of the ip addresses that were sent by my address (which I don't care about)
I can then use the following to extract the unique entries:
sort -u ips.txt > intermediate.txt
I don't know how I can aggregate the line counts somehow with sort.

Answer 1

You can use the uniq command to get counts of sorted repeated lines:
sort ips.txt | uniq -c
To get the most frequent results at top (thanks to Peter Jaric):
sort ips.txt | uniq -c | sort -bgr

Answer 2

To count the total number of unique lines (i.e. not considering duplicate lines) we can use uniq or Awk with wc:
sort ips.txt | uniq | wc -l
awk '!seen[$0]++' ips.txt | wc -l
Awk's arrays are associative so it may run a little faster than sorting.
Generating text file:
$ for i in {1..100000}; do echo $RANDOM; done > random.txt
$ time sort random.txt | uniq | wc -l
31175
real 0m1.193s
user 0m0.701s
sys 0m0.388s
$ time awk '!seen[$0]++' random.txt | wc -l
31175
real 0m0.675s
user 0m0.108s
sys 0m0.171s

Answer 3

This is the fastest way to get the count of the repeated lines and have them nicely printed sored by the least frequent to the most frequent:
awk '{!seen[$0]++}END{for (i in seen) print seen[i], i}' ips.txt | sort -n
If you don't care about performance and you want something easier to remember, then simply run:
sort ips.txt | uniq -c | sort -n
PS:
sort -n parse the field as a number, that is correct since we're sorting using the counts.