Local Variables: Keep Functions Isolated

Local variables are only in functions. Don't affect global. Use them.

Here's the thing: Use local variables in functions. Prevents conflicts. Keeps functions isolated.

Basic Local

count=0

function increment() {
    local count=$((count + 1))
    echo "$count"
}

increment
echo "$count"  # Still 0

My take: local makes variables local. Use it in functions.

Why It Matters

Without Local

name="Global"

function change() {
    name="Local"
}

change
echo "$name"  # Changed to "Local"!

My take: Without local, you change globals. Be careful.

With Local

name="Global"

function change() {
    local name="Local"
    echo "$name"
}

change
echo "$name"  # Still "Global"

My take: With local, globals stay safe. Use it.

Common Patterns

Always Use Local

function process() {
    local temp_file="/tmp/process_$$"
    local count=0
    # Use local variables
}

Common Mistakes (I've Made These)

1. Forgetting local: Always use local in functions. Prevents conflicts.

2. Changing globals: Don't change globals accidentally. Use local.

3. Not understanding scope: Understand where variables are available.

What's Next?

Now that you understand local variables, let's talk about Recursive Functions.

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Personal note: I used to forget local. Then I had conflicts. Now I always use local in functions. It prevents problems. Do it.