Bash Fundamentals

Overview

Bash is a command-line shell used heavily in Linux and Unix environments for system tasks, deployment automation, and CI pipelines.

Core Concepts

• Variables and command substitution
• Exit codes for command status
• Pipes and redirection
• Loops and conditionals

flowchart LR
    A[ls] --> B[grep]
    B --> C[sort]
    C --> D[tee output.log]

Practical Example

#!/usr/bin/env bash
set -euo pipefail

for file in *.log; do
  echo "Processing $file"
  grep -i error "$file" || true
done

Production Example

Release scripts frequently package artifacts, verify checksums, and publish to registries in Linux-based CI runners.

Common Pitfalls

• Missing set -euo pipefail in critical scripts
• Unquoted variables causing word splitting bugs
• Ignoring command exit codes in pipelines

Key Takeaways

• Bash is powerful for system automation and pipeline scripting.
• Defensive defaults prevent fragile script behavior.
• Quoting and exit-code checks are foundational practices.