Lesson 9: Advanced Bash Scripting

Why Advanced Bash Matters

Bash scripting is a core skill for DevOps engineers. Advanced Bash enables automation, error handling, system checks, and self-healing scripts used in production environments.

Conditional Statements

Conditionals allow scripts to make decisions.

if [ "$ENV" = "prod" ]; then
  echo "Production environment"
else
  echo "Non-production environment"
fi
    

Loops in Bash

• for – Iterate over lists
• while – Loop while condition is true
• until – Loop until condition becomes true

for server in server1 server2 server3
do
  ssh $server uptime
done
    

Functions

Functions help reuse logic and keep scripts clean.

check_service() {
  systemctl is-active nginx
}

check_service
    

Error Handling & Exit Codes

Every command returns an exit code. Handling errors properly is critical in automation.

command || exit 1
echo "Command succeeded"
    

Signals and Traps

Traps allow scripts to respond to signals such as interruptions or failures.

trap 'echo "Script interrupted"; exit 1' SIGINT SIGTERM
    

DevOps Use Cases

• Automated server health checks
• Log rotation and cleanup
• CI/CD pipeline scripts
• Self-healing automation

What You Learned

• Advanced conditionals and loops
• Reusable Bash functions
• Error handling and traps
• Real-world DevOps scripting patterns