The following template should be close to what you're looking for:

{{ if {{ authors match="[^,]+,[^,]+,[^,]+" }} }}
{{ authors max="1" suffix="-etal" }}
{{ else }}
{{ authors join=" and " }}
{{ endif }}
{{ year prefix="-"}}
{{ title truncate="80" replaceFrom="(\.|:|\?)(.*?)$" prefix="-" }}


File renaming template currently does not support counting authors, but we can use a regular expression to check if there are at least three authors. If that's the case, the first branch executes, producing author-etal. If there are fewer than three authors, the second branch executes, producing author and author.

Next, we display the year, prefixing it with a hyphen ("-").

Finally, we add the title, which uses regex to remove everything after a period (.), colon (:), or question mark (?). The title is truncated at 80 characters.

Zotero will always produce a valid filename, as special characters that are not allowed in filenames are removed in the final step.

-Only work with pdf,doc,docx,txt,rtf,djvu,epub

This can be specified using a hidden pref extensions.zotero.autoRenameFiles.fileTypes as explained on the file renaming page.

I couldn't find any documentation, but by looking at the source code, it seems that replace_blanks converts spaces to underscores in the final file name.

In the new Zotero templating system, you would need to specify this as case for every field where spaces might occur, something like:

{{ if {{ authors match="[^,]+,[^,]+,[^,]+" }} }}
{{ authors max="1" suffix="-etal" case="snake" }}
{{ else }}
{{ authors join=" and " case="snake" }}
{{ endif }}
{{ year prefix="-" }}
{{ title truncate="80" replaceFrom="(\.|:|\?)(.*?)$" prefix="-" case="snake" }}

That would work, except we've already used replaceFrom for the title, and there is currently no support for specifying more than one replacement for a value.

I'm afraid going with all lowercase 'snake_case' is the closest that the current Zotero template-based file renaming can do to match your naming pattern.

No, that would insert title twice, formatted in two different ways. My earlier template includes if/else switch to pick one or the other way of formatting the authors field.

@tnajdek Hi, I am so excited that the code really help me! Thanks a lot! By the way, is there a blank before and after authors? How can I do to eliminate it?

This is my setting:
{{ if {{ authors match="[^,]+,[^,]+,[^,]+" }} }}
{{ authors max="1" suffix=" et al" }}
{{ else }}
{{ authors join="_" }}
{{ endif }}

https://s3.amazonaws.com/zotero.org/images/forums/u9553762/o8bqhxmlrh8x1agn0icy.png

@tnajdek The problem is completely what you say in the first suggestion! I checked my setting and found that there is some space characters at the end of some lines. Thank you for this contribution!

@RamonMi

Unfortunately, the last part of your template won't work, as you can only specify one set of replaceFrom/replaceTo per variable. As I explained above, using case="snake" is the best the current system can do.

By the way, I am also curious about how to post the code in the form of a Markdown code block.

The forum supports a small subset of HTML tags. For code blocks, I'm using <code>.