Conditional change to {title} in jacket

[tgiladi]

Hi, I am following the guides and documentation on customizing my jacket template to fit my preferences.
One of the things I haven't figured out how to do yet, is conditionally changing the title of the book.
My use case is this: I keep a backup of all my books in a folder unrelated with my Calibre library. In this folder I name the books such that the series name and the book number in the series are part of the file name. It makes it easy to find the books I want when not using some DB like Calibre.
When I add these books into Calibre, I am keeping this naming convention as the title of the book. And of course, when I polish the books to add a jacket, the title is shown exactly like that (i.e. "Series Name #01 - Book Name").
This is redundant because the series details are also included in the jacket, and I would prefer to keep just the book name as the title in the jacket.
I was thinking of creating a custom column (e.g. short_name or something like that) where I would store just the book name, for books that are part of a series and then conditionally show that column as the title in the jacket, instead of the normal title. For books that are not part of a series, I would show the regular title in the jacket as normal.
I am familiar with IF statements in other languages, but I don't know if that's possible in html.
Is there a way to achieve what I'm looking for?
Thanks!

[tgiladi]

From the lack of responses I assume that either I wasn't clear enough with what I was asking, or maybe it's not possible.
But just in case someone else might have this type of question in the future, I'd like to explain what I ended up doing:
Since all I really wanted was to have the book's title in the jacket, but to also add the series information in the file name, I ended up cleaning my book title and removing the series name and index, and instead, I edited the save to disk template so when I save to my backup folder, the file name does include the series name and index, in my desired format:

{series} {series_index:0>2s|#| - }{title} - {authors}

I followed the instructions here: https://manual.calibre-ebook.com/template_lang.html

[theducks]

You are asking 2 different questions.
1)is how to modify the Jacket

Calibre has a brilliant system for users to have overrides.
If it sees a needed resource in the USERS configuration, that takes priority.
so place a copy of

C:\Program Files\Calibre2\app\resources\jacket

into

C:\Users\thedu\AppData\Roaming\calibre\resources

Note: This does not get updated when calibre does
This is where yo2 modify your 'jacket' look

2)file save template (THIS DOES NOT AFFECT THE LIBRARY. That can not be changed (See the FAQ Help)

[tgiladi]

Thanks for replying. I know how to modify the jacket by the method you described, I followed the documentation and managed to get it how I wanted it. I also managed to get the save to disk template formatted how I wanted it to be. So, my issue is solved.
I appreciate your help!