Chapter 11

1. How does an if-then(-else) statement end?
   With the reverse of the word if: fi
2. How can we use regular expression search patterns in a conditional evaluation?
   By employing the =~ comparison symbol. For example: [[ ${var} =~ [[:digit:]] ]]
3. Why do we need the elif keyword?
   If we want to sequentially test for more than one condition, we can use else if (elif).
4. What is nesting?
   Using an if-then-else statement or loop within another if-then-else statement or loop.
5. How can we get information about how to use shell builtins and keywords?
   By using the command help, followed by the builtin or keyword we want information about. For example: help [[
6. What is the opposite keyword of while?
   until. A while loop runs until the condition is no longer true, an until loop runs until the condition is no longer false.
7. Why would we choose the for loop over the while loop?
   for is more powerful...