What is the purpose of using quotes when referencing a shell variable with whitespace?

When referencing a shell variable that contains whitespace, quotes are used to ensure that the entire value of the variable is treated as a single argument. Without quotes, the shell would interpret the whitespace as a separator between different arguments, which can lead to errors or unexpected behavior.

Here’s an example:

# Without quotes
my_var="Hello World"
echo $my_var  # This works and outputs: Hello World

# With quotes
echo "$my_var"  # This also works and outputs: Hello World

In the second case, using quotes ensures that if the variable contains spaces, it is treated as one complete string rather than separate words. This is especially important when passing variables to commands or scripts that expect a single argument.