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String Operators: Compare And Manipulate Strings

String operators compare strings. Check if they're empty. Compare them.

Here's the thing: String operators are useful. Learn them. Use them.

Comparison Operators​

Equal​

if [ "$name" = "John" ]; then
    echo "Match"
fi

My take: = compares strings. Use it.

Not Equal​

if [ "$name" != "John" ]; then
    echo "Different"
fi

My take: != checks not equal. Use it.

Empty Checks​

-z: Empty String​

if [ -z "$name" ]; then
    echo "Empty"
fi

My take: -z checks if empty. Use it.

-n: Not Empty​

if [ -n "$name" ]; then
    echo "Has value"
fi

My take: -n checks if not empty. Use it.

String Length​

name="John"
length=${#name}
echo "$length"  # 4

My take: ${#var} gets length. Useful.

Common Patterns​

Check If Empty​

if [ -z "$input" ]; then
    echo "Input required"
    exit 1
fi

Compare Strings​

if [ "$status" = "active" ]; then
    echo "Running"
fi

What's Next?​

Now that you understand string operators, let's talk about Operator Precedence.

Personal note: String operators seemed simple. Then I learned them properly. Now I use them constantly. They're essential. Learn them.