use sort-uniq pipeline to show all events without duplications

Author: HassanOHOsman

shell-pipelines/sort-uniq-head-tail/script-05.sh

@@ -6,3 +6,4 @@ set -euo pipefail
 # TODO: Write a command to show a list of all events that have happened, without duplication.
 # The order they're displayed doesn't matter, but we never want to see the same event listed twice.
 # Your output should contain 6 lines.
+sort events.txt | uniq