List Newest Source Files Before Backup
Before trusting a backup, know which files changed most recently.
find source -type f -printf '%TY-%Tm-%Td %TH:%TM %p\n' | sort
problem area
Hosting Operations
Web hosting, SSL, DNS, Nginx, deployment, backups, and VPS management.
71 checked fixes
One-liners in this area
Create a SHA256 Checksum Manifest
A file list says what exists; checksums say whether bytes match.
sha256sum source/app/config.yml source/content/index.md source/content/about.md source/assets/logo.svg
Verify a SHA256 Checksum Manifest
A checksum file is only useful if you actually verify it.
sha256sum -c checksums.sha256
Compare Source and Backup File Lists
A backup can be missing files and still look plausible at a glance.
comm -3 <(find source -type f | sed 's#^source/##' | sort) <(find backup -type f | sed 's#^backup/##' | sort)
Preview Backup Drift with rsync
Rsync can tell you what would change before it changes anything.
rsync -ain --delete source/ backup/
Find Empty Files in a Backup
Zero-byte files can be normal, or they can be failed writes.
find backup -type f -size 0 -print
List Largest Files in a Backup
Large backup files are where storage surprises usually start.
find backup -type f -printf '%s %p\n' | sort -nr | head
Find Files Newer Than a Backup Snapshot
Files newer than the last snapshot are the ones most likely missing from it.
find source -type f -newer backup/.snapshot -print | sort
Check Whether PostgreSQL Is Accepting Connections
The database was running, but it was not ready.
pg_isready -h 127.0.0.1 -p 5432
Show Active PostgreSQL Connections
The database was not down. It was full.
psql -X -A -F '|' -c "select pid,usename,datname,state,client_addr from pg_stat_activity order by state, pid;"
Find Long-Running PostgreSQL Queries
One query can make the whole app look broken.
psql -X -c "select pid, now() - query_start as age, state, left(query, 80) as query from pg_stat_activity where query_start is not null order by age desc limit 10;"
Check PostgreSQL Lock Waits
The outage was a queue, not a crash.
psql -X -c "select pid, wait_event_type, wait_event, state, left(query, 80) as query from pg_stat_activity where wait_event_type is not null order by pid;"
Show PostgreSQL Database Sizes
Disk pressure starts with knowing what grew.
psql -X -c "select datname, pg_size_pretty(pg_database_size(datname)) as size from pg_database order by pg_database_size(datname) desc;"
Check Whether MySQL Responds
The port was open. MySQL still had to answer.
mysqladmin ping -h 127.0.0.1 -P 3306
Show Active MySQL Sessions
The app was waiting behind busy sessions.
mysql -e "show full processlist;"
Find Long-Running MySQL Queries
One old query explained the whole slowdown.
mysql -e "select id,user,host,db,command,time,state,left(info,80) as info from information_schema.processlist where command <> 'Sleep' order by time desc limit 10;"
Show MySQL Database Sizes
The storage alert needed a database name.
mysql -e "select table_schema, round(sum(data_length + index_length)/1024/1024, 1) as mb from information_schema.tables group by table_schema order by mb desc;"
Tail the Failing CI Lines
Skip the full CI log and jump straight to lines that usually explain the failure.
grep -RInE 'error|failed|exception|traceback|fatal' logs/ | tail -50
List Newest Build Artifacts
Confirm what your pipeline actually produced before you deploy it.
find artifacts/ -type f -printf '%TY-%Tm-%Td %TH:%TM %10s %p\n' | sort | tail -20
Show Release Directory Ages
See your newest release directories without opening a dashboard.
find releases/ -mindepth 1 -maxdepth 1 -type d -printf '%T@ %TY-%Tm-%Td %TH:%TM %p\n' | sort -nr | head -10 | cut -d' ' -f2-
Compare Artifact Checksums
Verify two artifact copies match before blaming deployment code.
sha256sum artifacts/app.tar.gz releases/current/app.tar.gz
Check Image Tags in Manifests
Find the image tags your deployment files reference without printing env values.
grep -RhoE 'image:[[:space:]]*[^[:space:]]+' deploy/ | sort -u
Show Containers in a Clean Triage Table
Turn noisy docker ps output into the few fields operators scan first.
docker ps -a --format 'table {{.Names}}\t{{.Status}}\t{{.Image}}\t{{.Ports}}'
Check Container Health Status
Docker may say a container is running while its health check says otherwise.
docker inspect --format '{{.Name}} health={{if .State.Health}}{{.State.Health.Status}}{{else}}none{{end}} status={{.State.Status}}' web
Snapshot Container CPU and Memory
Get Docker resource usage once, without leaving a live dashboard running.
docker stats --no-stream --format 'table {{.Name}}\t{{.CPUPerc}}\t{{.MemUsage}}\t{{.NetIO}}\t{{.BlockIO}}'
Summarize Docker Disk Usage
See how Docker storage is split across images, containers, volumes, and cache.
docker system df -v
See Container Network Attachments
A container can be healthy and still attached to the wrong network.
docker inspect --format '{{.Name}} {{range $name, $net := .NetworkSettings.Networks}}{{$name}} {{$net.IPAddress}} {{end}}' api
Test Nginx Before Reload
The config looked fine. Nginx disagreed before reload broke anything.
nginx -t
Show Enabled Nginx Sites
The config existed, but it was not enabled.
ls -l /etc/nginx/sites-enabled/
Find Which Nginx Config Owns a Domain
The wrong server block was answering the domain.
grep -R "server_name" /etc/nginx/sites-enabled/
Check HTTP to HTTPS Redirect
HTTPS worked. The plain HTTP redirect still mattered.
curl -I http://example.com
Inspect Response Headers
The page loaded, but the headers told the operational story.
curl -sI https://example.com
Check a Domain A Record
The site was fine. The domain was pointed somewhere else.
dig +short example.com A
List Certbot Certificates
The certificate existed. The question was which domains it covered.
certbot certificates
Check the Current Release Symlink
The deploy finished. The symlink told me what was actually live.
readlink -f /srv/www/example.com/current
Find Top 404 URLs
The missing file was not random. The access log had a pattern.
awk '$9==404 {print $7}' /var/log/nginx/access.log | sort | uniq -c | sort -nr | head
See Top Referrers
LinkedIn traffic was not a guess. The referrer field showed it.
awk -F'"' '{print $4}' /var/log/nginx/access.log | sort | uniq -c | sort -nr | head
Find the Processes Burning CPU
A server feels slow, but you need proof before restarting anything.
ps -eo pid,ppid,stat,pcpu,pmem,comm,args --sort=-pcpu | head -n 10
Find the Processes Eating Memory
Memory pressure can look like a slow app, a stuck deploy, or random crashes.
ps -eo pid,ppid,stat,pcpu,pmem,rss,comm,args --sort=-pmem | head -n 10
Check Inodes When Disk Space Looks Fine
Sometimes the disk has free bytes but still cannot create files.
df -ih
Find Open Deleted Files with lsof
A file can be deleted but still occupy disk while a process holds it open.
lsof +L1
Show One SQLite Table Schema
A failed query is often just a wrong assumption about column names.
sqlite3 app.db ".schema users"
Check SQLite Database Integrity
When a SQLite-backed app behaves strangely, first rule out file corruption.
sqlite3 app.db "PRAGMA integrity_check;"
List SQLite User Tables Only
System metadata tables can distract from the app tables you care about.
sqlite3 app.db "SELECT name FROM sqlite_master WHERE type='table' ORDER BY name;"
Count Rows in Key SQLite Tables
A quick row count can reveal empty imports, runaway events, or missing data.
sqlite3 app.db "SELECT 'users', count(*) FROM users UNION ALL SELECT 'orders', count(*) FROM orders UNION ALL SELECT 'events', count(*) FROM events;"
Show Indexes on a SQLite Table
Slow lookups often start with missing or misunderstood indexes.
sqlite3 app.db "PRAGMA index_list('orders');"
Show Recent SQLite Events
For small apps, the quickest timeline may be inside the SQLite file.
sqlite3 app.db "SELECT created_at, event_type FROM events ORDER BY created_at DESC LIMIT 5;"
Count SQLite Events by Type
A noisy event type stands out faster when you group it.
sqlite3 app.db "SELECT event_type, count(*) FROM events GROUP BY event_type ORDER BY count(*) DESC;"
Find Duplicate Emails in SQLite
Duplicate account data is easier to spot with one grouped query.
sqlite3 app.db "SELECT email, count(*) FROM users GROUP BY email HAVING count(*) > 1;"
Back Up a SQLite Database File
Copying a live SQLite file blindly can produce a bad backup.
sqlite3 app.db ".backup backup/app.db"
Find Duplicate Page Titles
Duplicate titles make a static site harder to scan in search results and browser tabs.
grep -Rho --include='*.html' '[^<]* ' public | sed 's###;s# ##' | sort | uniq -c | sort -nr
Find Pages Missing Canonical Links
Canonical tags are easy to drop when templates branch.
find public -name '*.html' -print | while read -r f; do grep -qi 'rel="canonical"' "$f" || echo "$f"; done
Find Pages Marked noindex
A leftover noindex can hide a page after launch.
grep -Rni --include='*.html' 'noindex' public
Find Pages Missing Meta Descriptions
Missing descriptions are usually a content template problem, not a mystery.
find public -name '*.html' -print | while read -r f; do grep -qi 'name="description"' "$f" || echo "$f"; done
Check robots.txt for a Sitemap Line
A sitemap can exist and still be hard to discover.
grep -n '^Sitemap:' public/robots.txt
Find HTML Pages Missing from the Sitemap
A page can exist in the build but never make it into the sitemap.
find public -name '*.html' -print | sed 's#^public#https://example.com#' | while read -r url; do grep -q "$url" public/sitemap.xml || echo "$url"; done
Find Pages Missing og:title
Social previews often fail because one template missed Open Graph tags.
find public -name '*.html' -print | while read -r f; do grep -qi 'property="og:title"' "$f" || echo "$f"; done
Find Feed Links Missing from the Sitemap
Your feed can advertise URLs that the sitemap never lists.
grep -o 'https://example.com/[^<]*' public/feed.xml | sed 's###;s###' | while read -r url; do grep -q "$url" public/sitemap.xml || echo "$url"; done
List Nginx Listen Directives
The site was configured, but the port was not.
grep -RInE '^[[:space:]]*listen[[:space:]]' fixtures/nginx/conf.d fixtures/nginx/sites-enabled
Find the Nginx Default Server
The wrong site answered because it was the fallback.
grep -RIn 'default_server' fixtures/nginx/conf.d fixtures/nginx/sites-enabled
Show Nginx Include Lines
The config was valid; it just was not included.
grep -RInE '^[[:space:]]*include[[:space:]]' fixtures/nginx/nginx.conf fixtures/nginx/conf.d fixtures/nginx/sites-enabled
Map Nginx Roots and Aliases
The URL was right. The filesystem path was not.
grep -RInE '^[[:space:]]*(root|alias)[[:space:]]' fixtures/nginx/conf.d fixtures/nginx/sites-enabled
Map Nginx Proxy Targets
Nginx was healthy. It was proxying to the wrong place.
grep -RInE '^[[:space:]]*proxy_pass[[:space:]]' fixtures/nginx/conf.d fixtures/nginx/sites-enabled
Show Enabled Apache Sites
The Apache config existed. The enabled symlink did not.
find fixtures/apache/sites-enabled -maxdepth 1 -type l -printf '%f -> %l\n' | sort
Map Apache Virtual Hosts
Apache chose a virtual host. You need to know which one.
grep -RInE '
Find Apache Document Roots
Apache was serving files from a different directory than expected.
grep -RInE '^[[:space:]]*DocumentRoot[[:space:]]' fixtures/apache/sites-enabled
Map Apache Proxy Rules
Apache was up. The reverse proxy target was wrong.
grep -RInE '^[[:space:]]*(ProxyPass|ProxyPassReverse)[[:space:]]' fixtures/apache/sites-enabled
Find Web Server Redirect Rules
The redirect loop was hiding in plain text.
grep -RInE 'return[[:space:]]+30[18]|rewrite[[:space:]]|Redirect[[:space:]]|RewriteRule|RewriteCond' fixtures/nginx fixtures/apache
Summarize HTTP Status Codes
Before chasing individual lines, get the shape of the whole log.
awk '{count[$9]++} END {for (code in count) print count[code], code}' ./fixtures/nginx/access.log | sort -nr
Group Server Errors by URL Path
A 500 spike is easier to triage when the broken path is obvious.
awk '$9 ~ /^5/ {count[$7]++} END {for (path in count) print count[path], path}' ./fixtures/nginx/access.log | sort -nr | head
Find Unusually Large Web Responses
A few huge responses can explain bandwidth, latency, and suspicious download patterns.
awk '$10 ~ /^[0-9]+$/ && $10 > 1000000 {print $10, $1, $7, $9}' ./fixtures/nginx/access.log | sort -nr | head