How to count occurrences with awk

How to count occurrences with awk

Count unique values, word frequencies, and pattern occurrences in text files using awk associative arrays.

Prerequisites

• awk installed.

Step-by-Step: Count Occurrences with awk

1. Count occurrences of each unique value in a column. awk uses associative arrays to tally values:

   awk '{count[$1]++} END {for (val in count) print val, count[val]}' access.log

2. Count HTTP status codes from an Nginx access log (status code in field 9):

   awk '{count[$9]++} END {for (code in count) print code, count[code]}' /var/log/nginx/access.log | sort -rn -k2

3. Count unique IP addresses:

   awk '{ips[$1]++} END {print "Unique IPs:", length(ips)}' /var/log/nginx/access.log