log_summary.sh in Bash

A log triage in pure shell: buckets, top paths, the slow tail.

#!/usr/bin/env bash
# log_summary: status buckets, top paths and error lines from a log
set -euo pipefail

log=$(mktemp)
trap 'rm -f "$log"' EXIT
cat > "$log" <<'EOF'
GET /api/users 200 45
POST /api/login 401 12
GET /api/users 200 38
GET /static/app.js 200 5
POST /api/orders 500 220
GET /api/users 304 9
EOF

echo "== status buckets =="
awk '{ print substr($3, 1, 1) "xx" }' "$log" | sort | uniq -c

echo "== top paths =="
awk '{ print $2 }' "$log" | sort | uniq -c | sort -rn | head -3

echo "== slowest =="
sort -k4 -rn "$log" | head -1

errors=$(awk '$3 >= 500 { print $2 }' "$log")
echo "5xx on: ${errors:-none}"

How it works

awk buckets statuses into 2xx/4xx/5xx with substr.
sort | uniq -c | sort -rn ranks the paths.
sort -k4 -rn finds the slowest request by column.

Keywords and builtins used here

echo
set
trap

The run, in numbers

Lines: 26
Characters to type: 617
Tokens: 85
Three-star pace: 80 tpm

At the three-star pace of 80 tokens a minute, this run takes about 64 seconds.

Type this snippet

Step 1 of 2 in Encore, step 25 of 26 in Language basics.

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