If you're tailing logs, can I suggest that you try out the Logfile Navigator (https://lnav.org). It really is possible to do better than tail/less/whatever when you just want to look at a local log file:
I mention it both because I find it very useful and because, seeing Logfile Navigator, I now see that it desperately needs to have more features :).
This: https://lnav.org/features#query-logs-using-sql
Reminded me of: logParser https://www.microsoft.com/en-us/download/details.aspx?id=246...
I think inline pretty-print of JSON/XML/YAML in a log entry.. plus histogram of date/time.. I do these things a lot using various grep/sort/uniq etc pipelines
Wow!
https://docs.lnav.org/en/latest/commands.html#adjust-log-tim...
That can be useful for doing minor alignments if clocks are slightly out of sync or doing timezone adjustments.
You can also adjust the time programmatically by updating the "time_offset" column in the "lnav_file" table:
https://docs.lnav.org/en/latest/sqltab.html#lnav-file
Sorry I don't have any examples written up to illustrate this at the moment...
With my old log merging program, you had to supply a regex with groups for the different timezone components and optionally a UTC offset. That worked really well but was a pain to set up. Typically I was using it to look at the same format of files all the time though, so in practice it wasn't that bad.
I'm not really a C/C++ person but maybe I'll try and hack on lnav a bit and see if I can figure out how to add timezone support.