How to sort results from ls command by modification date (directories first)?

what about something like this:

ls -ltr --group-directories-first

ls -t

or (for reverse, most recent at bottom):

ls -tr

The ls man page describes this in more details, and lists other options.

Directories have d in front of there permissions in ls -ltr

So to get directories with sorted modification date use

ls -ltr |grep ^d

And to files other than directories

ls -ltr | grep -v ^d