Suppose I want to taking up writing a personal log, as described in the human log; never mind if it's about personal life, health, professional matters etc.
The log will have text - some of it possibly categorized. It may also have several numeric values and text fields which I want to track - which I may also want to categorize/place in named sets. Keywords or links may be desirable; something like markdown for free text fields would also be nice.
I could theoretically just write text files. Or - insert log entries into a LibreOffice spreadsheet. But... that seems not convenient enough. Not inviting. I'm wondering whether there are log-keeping applications which support most/all what I want to do, are gratis, and available for Linux. Libre software is a plus.
Note: The log is to be private and not placed online. And - it's not a blog (although exporting to blog entries could be a feature I suppose).
Finally - I mostly use a desktop computer, but an Android up for tapping new entries could be useful too.