[bash conditional expressions](https://www.gnu.org/software/bash/manual/html_node/Bash-Conditional-Expressions.html) can be used to solve this exercise.
[bash conditional expressions](https://www.gnu.org/software/bash/manual/html_node/Bash-Conditional-Expressions.html) can be used to solve this exercise. When using those expressions, you only need to take into account it's default behavior.