How to show/sort system date of a (epub) file

[PalingB]

Is it possible to show the date of an (epub)file and
sort on that date?
I tried to find a solution in the forums if overlooked it.....

[kiwidude]

Not that I am aware of. Remember that calibre is designed to have multiple formats per book record, so it doesn't make sense to have a column that contains data specific to one of those formats. The "size" column is an example of where such attempts fall down - it shows the size of the "largest" format attached, but users with more than one format will find that column pretty useless.

There is a column for the date the book was added to calibre, and a date the book record in calibre was last modified, both are unrelated to the date of the underlying file. Perhaps if you explain why you would want that date we could suggest an alternative, I don't recall ever seeing it being asked for before other than in relation to duplicates (for which the Find Duplicates plugin is a better solution).

[theducks]

Kiwidude is correct.
If you want to know the timestamp of a specific format of a title,
Hover (your mouse pointer) over that format in the Metadata editor.

Note that many activities can update those timestamps.

[PalingB]

Thank you for your reply.
Most of the files are scanned by volunteers, not commercial epubs.
I modify an ebook to the capabilities the ereader(Sony PRS-650) and myself.
In fact editing/replacing the style sheet, font-size and font-family
to have a maximum effect: the maximum number readable characters on the display.
The capabilities of Calibre to edit/modify a epub is often not enough for me.
I use Sigil(quality check of structure etc..), Topstyle and EditPadPro to edit style sheet and (x)html files.
When I directly modify a file from the library, the date, of course, doesn't change.
To day I modify new files before I insert them in the library, however the library contains more than 2000 unmodified
files and I like to see which files are "still to do".
Comparing file dates against the date I started to modify "old" files.

[kiwidude]

The extra info is great, thanks for that. The only options I can suggest are:

(1) Use a custom column or tag to track which books you have processed instead (that is what I do, a simple yes/no column). However that does rely on you editing from calibre to conveniently flip the yes/no after editing. And won't help you figure out the backlog.

(2) Roll your Python sleeves up and write a simple plugin to do it for you. It could populate a custom column when run with the latest timestamp.

(3) Perhaps chaley's template language for custom columns would support something like this. I would be surprised if it did, because it would be intolerably slow everytime you started calibre with a big library like yours. But I've never really looked into that language since my own column needs are too simple. Again it requires some head-scratching/coding thinking, though chaley is very good at helping out. Certainly if he spots this thread he can say whether this option is even possible.

If it was me and I was in the situation of already having thousands of books "done" already without a custom column, I would write a plugin for it. But then I've already been through that Python/plugin learning curve...

[davidfor]

For something similar to this, I use kiwidudes Reading List plugin. I use a different lists for each possible state. Adding/removing from each list also maintains a column. In this case it is a "State" column which has possibilities of "unclean", "cleaning" and "cleaned".

This is basically what kiwidude's point 1 is describing but with more states and the plugin involvement.

[chaley]

Originally Posted by PalingB

Is it possible to show the date of an (epub)file and
sort on that date?

Yes.

Create a composite custom column (column built from other columns). Set the sort/search type to date. Do not show in tag browser. Do not show checkmarks. Use the following template

program: list_re(formats_modtimes('yyyy-MM-dd hh:mm:ss'), ',', 'EPUB:(.)', '\1')

You can change the date format (the yyyy... stuff) to whatever you want.

The new column will either be empty or contain the mod date for the epub format for the book. Sorting and searching on the column will work.

Do note that adding this column will have an impact on performance. Sorting on the column will require looking up the mod time of every format in your library. Try it. If you don't like the resulting performance, then delete the column and go to plan B.

[kiwidude]

I had suspected the arcane arts of the calibre custom column language might reveal a solution

[PalingB]

Thank you Chaley!
For now I can live with the perfomance penalty.

[read113]

Charley
I created the column as you said, I think but I must be doing it wrong because all that shows in the column is:
"Program: list_re(formats_modtimes('yyyy-MM-dd hh:mm:ss'), ',', 'EPUB.)', '\1')

Is there a check box or switch I missed? Can I change EPUB to MOBI and have it still work.

Sorry I am not a programmer. Thanks

[chaley]

Originally Posted by read113

Charley
I created the column as you said, I think but I must be doing it wrong because all that shows in the column is:
"Program: list_re(formats_modtimes('yyyy-MM-dd hh:mm:ss'), ',', 'EPUB.)', '\1')

Is there a check box or switch I missed? Can I change EPUB to MOBI and have it still work.

Sorry I am not a programmer. Thanks

The template must begin with "program" (all lower case), not "Program". In general, when working with program-like things such as templates, letter case matters. For example, note the "MM" and "mm". One means month, and the other means minute.

And yes, you can change EPUB to MOBI.

[read113]

Charley

Thank you for all you help. Changing "P" in Program to "p" did just what you said.