📜 Scripts and Shebang

Scripts allow you to save sequences of commands for repeated execution. The shebang line tells the system how to interpret the script.

🧭 Creating a Script

Create a new file with a .sh extension:

nano myscript.sh

Write your commands:

#!/bin/sh
echo "Hello, World!"
date

Make it executable:

chmod +x myscript.sh

Run it:

./myscript.sh

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🔧 Shebang Explained

First line specifies interpreter:

#!/bin/sh

Other common shebangs:

#!/bin/bash
#!/bin/zsh
#!/usr/bin/env python3
#!/usr/bin/perl

Using env locates interpreter dynamically:

#!/usr/bin/env node

Important considerations: - Must be first line (no blank lines before!) - Points to actual executable path - Not necessary for sourced files

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🧪 Running Scripts

Several methods exist:

Method	Notes
./script.sh	Requires execute permission
sh script.sh	Runs regardless of permissions
source script.sh	Runs in current shell context
. script.sh	Same as source

Choosing depends on desired scope and reusability.

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🧾 Summary

• Scripts bundle commands for reuse.
• Shebang determines interpreter.
• Make scripts executable with chmod +x.
• Consider portability when choosing interpreter.

👉 Continue to: Portability