07 Jun 18 06:27, you wrote to me:

 GK>>> Might simply start with not easily being able to delete them
 GK>>> anymore on the commandline under *ix systems.

 ac>> If you're referring to filename globbing done by the shell, then
 ac>> yes, this can be a problem if you reach the kernel's limit for the
 ac>> length of the command or number of arguments.

 GK> That's what I was referring to. Of course there are ways around that, so
 GK> I wrote "not easily", i.e., not the usual way.

Well, not the DOS way. :-)

For me, using "find" is the usual way.

 ac>> find . -iname '*.msg' -delete

Actually this will delete *.msg in subdirectories too. And also
subdirectories with names matching that pattern.

Use this instead:

find . -depth 1 -type f -iname '*.msg' -delete

Omit -delete if you just want a list of files that it will delete.

I'll admit none of the parameters above are terribly self-evident, but
neither were DOS commands when we first learned them. We just take them for
granted now.

 GK> Might take for ages, too. find is slow with that. I've had directories
 GK> with many files, and even doing "ls -l" is getting slow
pretty soon. Try
 GK> it with 50k of files, and you'll see what I mean.

This hasn't been my experience on modern PCs. Especially not with
journaling filesystems on an SSDs.

50,000+ messages in an echo is an edge case, though. Most echos rarely see
that much traffic these days andtThere is not usually a need for anyone to
keep that many messages anyway.

--- GoldED+/BSD 1.1.5-b20170303