25 Real-World Scripting Tasks Every DevOps Engineer Should Know

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1. Monitor Disk Usage and Alert if Over 80%

#!/bin/bash
usage=$(df / | awk 'NR==2 {print $5}' | sed 's/%//')
[ "$usage" -gt 80 ] && echo "Disk usage is above 80%! ($usage%)"

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2. Clean /tmp Directory Older Than 7 Days

#!/bin/bash
find /tmp -type f -mtime +7 -exec rm -f {} \;

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3. Monitor Web Service and Alert on Failure

#!/bin/bash
URL="http://yourservice.com"
curl -s --head $URL | grep "200 OK" > /dev/null || echo "Service down!"

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4. Rotate Logs and Keep Last 5

#!/bin/bash
cd /var/log/myapp
ls -tp | grep -v '/$' | tail -n +6 | xargs -I {} rm -- {}

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5. Backup MySQL DB Daily With Timestamp

#!/bin/bash
mysqldump -u root -pYourPassword dbname > /backup/db_$(date +%F).sql

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6. Validate IPs in a Text File

#!/bin/bash
grep -Eo '([0-9]{1,3}\.){3}[0-9]{1,3}' ips.txt | while read ip; do
  if [[ $ip =~ ^([0-9]{1,3}\.){3}[0-9]{1,3}$ ]]; then echo "Valid: $ip"; fi
done

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7. Ping Servers from a File

#!/bin/bash
while read ip; do
  ping -c 1 $ip > /dev/null && echo "$ip is up" || echo "$ip is down"
done < servers.txt

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8. Email Top CPU-consuming Processes

#!/bin/bash
ps -eo pid,comm,%cpu --sort=-%cpu | head -n 6 | mail -s "Top CPU processes" you@example.com

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9. SSH into Multiple Servers and Execute Commands

#!/bin/bash
while read server; do
  ssh user@$server 'uptime'
done < servers.txt

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10. Archive Application Logs to S3

#!/bin/bash
tar czf app_logs_$(date +%F).tar.gz /var/log/myapp/
aws s3 cp app_logs_$(date +%F).tar.gz s3://your-bucket-name/

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11. Restart Service if Down

#!/bin/bash
if ! systemctl is-active --quiet nginx; then
  systemctl restart nginx
fi

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12. Tail Multiple Logs in Parallel

#!/bin/bash
tail -f /var/log/app1.log /var/log/app2.log

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13. Monitor SSL Certificate Expiry

#!/bin/bash
echo | openssl s_client -servername example.com -connect example.com:443 2>/dev/null | openssl x509 -noout -enddate

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14. Count Failed Logins in Log File

#!/bin/bash
grep "Failed password" /var/log/auth.log | wc -l

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15. Report Users with UID > 1000

#!/bin/bash
awk -F: '$3 > 1000 {print $1, $3}' /etc/passwd

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16. Find and Kill Zombie Processes

#!/bin/bash
ps aux | awk '$8=="Z" {print $2}' | xargs -r kill -9

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17. Compare Two Directories

#!/bin/bash
diff -r dir1/ dir2/

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18. Monitor Network Bandwidth in Real-Time

#!/bin/bash
iftop

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19. Create Users from CSV

#!/bin/bash
while IFS=, read -r user pass; do
  useradd -m $user && echo "$user:$pass" | chpasswd
done < users.csv

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20. Alert if Docker Container Not Running

#!/bin/bash
! docker ps | grep -q mycontainer && echo "Container is not running!"

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21. Auto-Deploy Static Site Using rsync

#!/bin/bash
rsync -avz /path/to/site/ user@server:/var/www/html/

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22. Git Pull + Restart Service

#!/bin/bash
cd /opt/myapp && git pull && systemctl restart myapp

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23. Generate Ansible Dynamic Inventory

#!/bin/bash
cat <<EOF
{
  "all": {
    "hosts": ["192.168.1.10", "192.168.1.11"]
  }
}
EOF

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24. Validate YAML and JSON Files

#!/bin/bash
yamllint file.yaml
jq empty file.json

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25. Parse Jenkins Job Status via API

#!/bin/bash
status=$(curl -s http://jenkins/job/myjob/lastBuild/api/json | jq -r '.result')
[ "$status" != "SUCCESS" ] && echo "Build failed!"

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