Open `less` scrolled to the end

less +G app.log

+ will run an initial command when the file is opened

G jumps to the end

When multiple files are in play, ++ applies commands to every file being viewed. Not just the first one. For example, less ++G app1.log app2.log.

less +F filename

will go to the end and tail the file.

From less man page:

F Scroll forward, and keep trying to read when the end of file is reached. Normally this command would be used when already at the end of the file. It is a way to monitor the tail of a file which is growing while it is being viewed. (The behavior is similar to the "tail -f" command.)

From the less man page:

If a command line option begins with +, the remainder of that option is taken to be an initial command to less. For example, +G tells less to start at the end of the file rather than the beginning, and +/xyz tells it to start at the first occurrence of "xyz" in the file. As a special case, + acts like +g; that is, it starts the display at the specified line number (however, see the caveat under the "g" command above). If the option starts with ++, the initial command applies to every file being viewed, not just the first one. The + command described previously may also be used to set (or change) an initial command for every file.