ls -t option flag sorts files/directories list by time/date.
$ ls -t [options] [file|dir]
Default list:
$ ls
Desktop Downloads Pictures Templates Videos
Documents Music Public todo.txt
$
List sorted by time/date
$ ls -t
Pictures Desktop Downloads Public Videos
todo.txt Documents Music Templates
$
Long listing format sorted by date/time:
$ ls -lt
total 4
drwxr-xr-x 2 user user 120 2011-08-17 18:14 Pictures
-rw-r--r-- 1 user user 131 2011-08-17 18:07 todo.txt
drwxr-xr-x 2 user user 80 2011-08-17 16:52 Desktop
drwxr-xr-x 2 user user 40 2011-08-17 16:52 Documents
drwxr-xr-x 2 user user 40 2011-08-17 16:52 Downloads
drwxr-xr-x 2 user user 40 2011-08-17 16:52 Music
drwxr-xr-x 2 user user 40 2011-08-17 16:52 Public
drwxr-xr-x 2 user user 40 2011-08-17 16:52 Templates
drwxr-xr-x 2 user user 40 2011-08-17 16:52 Videos
$