Re: Cat among the pigions but...
I'm puzzled by people that raise the bogey man of "binary logging"
It's really not _that_ hard to discover that the command 'journalctl' will spew out the contents of those log files, as text, with the added bonus of having the opportunity to add options that give you the logs from this boot, or any previous boot, or only logs associated with particular binaries or services (if you can work out the not very memorable options required).
You can pipe that into the grep command that you were going to point at your logs, and get the same result, with the added bonus that you don't have to guess the right log file, or wonder if some of the messages you were looking for went elsewhere, or decompress the older compressed (and hence binary) logs, and then sod about stitching them back together with cat if you want to grep back across several of those log files.
Not that any of that's particularly relevant to Debian, which still defaults to running rsyslogd, with its normal text files, and will only do binary logging if you choose to create the /var/log/journal/ directory.