Cybersecurity Triage
Read-onlySpot Request Bursts by Minute
You need to find the busiest minute-level windows in an access log.
Command
awk '{minute=substr($4,2,17); count[minute]++} END {for (m in count) print count[m], m}' ./fixtures/nginx/access.log | sort -nr | headBefore you run this
System impact: Read-only. Low when scoped to the shown target.
When not to use it: Do not use minute buckets for precise incident timelines; preserve raw logs for detailed analysis.
Expected output
A descending list of request counts followed by minute timestamps.
System impact
Read-only. Nothing changes. The command groups requests by minute and prints the busiest buckets.
Recovery / rollback: no state is changed.
When to use it
Use this when checking whether suspicious traffic is steady background noise or a short burst.
When not to use it
Do not use minute buckets for precise incident timelines; preserve raw logs for detailed analysis.
Watch this command run
Command transcript
This sanitized transcript shows the commands and output shape without exposing host details.
$ awk '{print substr($4,2,17)}' ./sample-files/nginx/access.log | head
25/Jun/2026:10:00
25/Jun/2026:10:00
25/Jun/2026:10:00
25/Jun/2026:10:01
25/Jun/2026:10:01
25/Jun/2026:10:01
25/Jun/2026:10:01
25/Jun/2026:10:01
25/Jun/2026:10:01
25/Jun/2026:10:01$ awk '{minute=substr($4,2,17); count[minute]++} END {for (m in count) print count[m], m}' ./sample-files/nginx/access.log | sort -nr | head
7 25/Jun/2026:10:01
5 25/Jun/2026:10:04
5 25/Jun/2026:10:03
5 25/Jun/2026:10:02
3 25/Jun/2026:10:00$ awk '{minute=substr($4,2,17); count[minute]++} END {for (m in count) print count[m], m}' ./sample-files/nginx/access.log | sort
3 25/Jun/2026:10:00
5 25/Jun/2026:10:02
5 25/Jun/2026:10:03
5 25/Jun/2026:10:04
7 25/Jun/2026:10:01View commands shown
These are the commands shown in the sanitized transcript.
Commands shown
awk '{print substr($4,2,17)}' ./fixtures/nginx/access.log | headawk '{minute=substr($4,2,17); count[minute]++} END {for (m in count) print count[m], m}' ./fixtures/nginx/access.log | sort -nr | headawk '{minute=substr($4,2,17); count[minute]++} END {for (m in count) print count[m], m}' ./fixtures/nginx/access.log | sort
next steps
Related commands
Find the IPs Creating the Most 4xx Noise
One address can turn a normal access log into a wall of failed requests.
awk '$9 ~ /^4/ {count[$1]++} END {for (ip in count) print count[ip], ip}' ./fixtures/nginx/access.log | sort -nr | head
Find Paths Repeatedly Returning 404
One missing URL is normal. A repeated missing URL is a signal.
awk '$9==404 {count[$7]++} END {for (path in count) if (count[path] >= 3) print count[path], path}' ./fixtures/nginx/access.log | sort -nr | head
Find Clients Repeating the Same Path
The suspicious pattern is sometimes one client hammering one URL.
awk '{key=$1 " " $7; count[key]++} END {for (k in count) if (count[k] >= 5) print count[k], k}' ./fixtures/nginx/access.log | sort -nr | head
Count the Most Common User Agents
A strange traffic spike often has a strange user agent.
awk -F'"' '{print $6}' ./fixtures/nginx/access.log | sort | uniq -c | sort -nr | head
Find Common Admin Probe Paths
A site does not need WordPress to receive WordPress-looking probes.
awk '$7 ~ /(admin|login|wp-|phpmyadmin)/ {print $1, $7, $9}' ./fixtures/nginx/access.log | sort | uniq -c | sort -nr | head
Study mapping
Use this as independent command practice: read the notes, predict the output, then compare it with the example before using a real shell.
Useful for
- LPIC-1 style command-line practice
- LFCS style performance tasks
- Linux+ style troubleshooting review
Independent study support only. No affiliation, endorsement, exam dumps, or real exam questions.