> Oh, I don´t know the name of the log for this process I can see in 'ps aux',
With services using journald, there's no "name of the log" because everything's in the journal, so that part isn't a problem. Rather than "is this in auth.log or syslog or thisservice.log", it'll always be in the journal.
> let me cd into /var/log and see what filenames I can find
You can filter journal entries by unit (-u) or by service identifier (-t). Often, though, I find it really useful to be able to see the adjacent entries from other services at the same time, since that can give some indication of what's happening on the system that caused an issue.
> or grep everything until I can find a couple of words that make some sense so I can keep digging further
journalctl --grep, or more conveniently, journalctl and then / to search.
> The lack of explorability in journalctl
It's explorable by dozens of different axes, and if all of those aren't sufficient, you always can get the whole thing as text and run any command you like on it, or get it in structured form and do structured queries on it.
With services using journald, there's no "name of the log" because everything's in the journal, so that part isn't a problem. Rather than "is this in auth.log or syslog or thisservice.log", it'll always be in the journal.
> let me cd into /var/log and see what filenames I can find
You can filter journal entries by unit (-u) or by service identifier (-t). Often, though, I find it really useful to be able to see the adjacent entries from other services at the same time, since that can give some indication of what's happening on the system that caused an issue.
> or grep everything until I can find a couple of words that make some sense so I can keep digging further
journalctl --grep, or more conveniently, journalctl and then / to search.
> The lack of explorability in journalctl
It's explorable by dozens of different axes, and if all of those aren't sufficient, you always can get the whole thing as text and run any command you like on it, or get it in structured form and do structured queries on it.