BASH – How to count the number of IP addresses in a log file

Background

Sometimes it’s useful to see how many times a specific IP address appears in a log file. In this article we explore one method using grep and uniq.

grep -E -o "([0-9]{1,3}[\.]){3}[0-9]{1,3}" /path/to/sourcefile | sort > output.txt

then

uniq -c output.txt | awk '{print $2": "$1}'

References

• https://unix.stackexchange.com/questions/390246/extracting-ip-addresses-from-a-log-file-and-list-them-in-another-file
• https://unix.stackexchange.com/questions/118333/counting-number-of-times-each-ip-address-appears-in-log-file