tsort:tldr:1a8f7

This command is used to sort a list of items using the topological sort algorithm.

Here's a breakdown of the command:

1. The echo command outputs the specified string: "${UI Backend\nBackend Database\nDocs UI}".
2. The -e option in echo enables the interpretation of escape sequences within the string. In this case, \n is used to represent a newline character, which separates the items in the list.
3. The output string is then piped (|) to the tsort command.
4. The tsort command takes the input and performs a topological sort on the items in the list.
5. After the sort is completed, the sorted output is displayed.

In summary, this command takes a list of items, separates them by newlines, performs a topological sort on the list, and then displays the sorted items.