Quoting is important for string expansion in bash. With these, you can control how the bash parses and expands your strings.

There are two types of quoting:

• Weak: uses double quotes: “
• Strong: uses single quotes: ’

If you want to bash to expand your argument, you can use Weak Quoting:

#!/usr/bin/env bash
world="World"
echo "Hello $world"
#> Hello World

If you don’t want to bash to expand your argument, you can use Strong Quoting:

#!/usr/bin/env bash
world="World"
echo 'Hello $world'
#> Hello $world

You can also use escape to prevent expansion:

#!/usr/bin/env bash
world="World"
echo "Hello \$world"
#> Hello $world

For more detailed information other than beginner details, you can continue to read it here.