1. You can use Enumerator to iterate over the elements of an array lazily. Here's a simple example: ```ruby array = [1, 2, 3]

enum = array.each_with_object([]) { |element, memo| memo << element }

enum.take(2) # => [1, 2]
``
In this example, we create an enumerator usingArray#each_with_object, which returns an enumerator object that yields each element of the array and appends it to the given accumulator (in this case, an empty array). We then take the first two elements from the enumerator (enum.take(2)), which will be[1, 2]`.

1. The -x or --exit-on-failure option is used with Bash scripts to stop the execution of the entire script if any command within it fails. This ensures that the script does not continue running even if some commands fail.

Here's how you would use the -x option in a Bash script:
```bash

!/bin/bash

set -e # Enable exit on error

echo "Hello World" && echo "This command should succeed" || echo "This command failed"
``
In this example, we set the-eoption for Bash to enable exiting on error. Then, we have two commands separated by the&&` operator, which means that the second command will only execute if the previous command succeeded. If either command fails, the script will terminate immediately.