You are probably trying to solve a problem in a fundamentally wrong way, and since you don't describe your problem - that is what you want to achieve or why you want to use trash I can only speculate on alternative approaches.
The easiest way for you to achieve undeletion is of course not to remove the file at all. Rather, you can rename it in a way that it is no longer found by the XAMPP installation, or move it for safe keeping in another directory, taking note of where it were, in case you need to restore it. (This is actually what trash does.)
What you probably want to do, however, judging from your statement in a comment that you are doing this for development purposes, is to version control your XAMPP installation. This will give you not only the ability to restore removed files, but also to track edits and added files, and be able to restore any point in the history of your development.
The good news is that it is really not that hard. Go to the
/opt/lampp directory, and type
$ git init
$ git add *
$ git commit
This will give you a clean starting point in your version history.
$ git rm <file>
to remove a file, and then commit your change. You can check your commit history with
$ git log
and if you change your mind, you can revert a change with the
$ git revert <id>
-command, where is the number displayed by