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Text Processing: awk and sed
Text Processing: awk and sed awk splits each line into columns: $1, $2 and so on. sed finds and replaces text. Both are Linux text tools. awk '{print $1}' access.log | sort | uniq -c | sort -nr | head This lists the IPs that sent the most requests to a web server. In a brute-force or scan, the attac
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What it is
awk splits each line into columns: $1, $2 and so on. sed finds and replaces text.
Both are Linux text tools.
Example
awk '{print $1}' access.log | sort | uniq -c | sort -nr | head
This lists the IPs that sent the most requests to a web server.
Why it matters for security
In a brute-force or scan, the attacker’s IP jumps to the top of that list in seconds.
Common mistake
Running sed -i (edit in place) on a live config first.
Run it without -i, check the output, then add -i.
Learn more in the lesson: 6.3 Text Processing: awk and sed