how to make more display only few lines at a time?
less -10 &lt;file&gt; on macOS 10.13 also scrolls forward 10 lines at a time.  The major difference is that it fills the first screen, as opposed to more which only generates the specified number of lines even on the first screen.

If that's not acceptable, the LINES env variable can override the number of lines on the screen.  So something like 

env LINES=10 less &lt;file&gt; 

will force 10 lines on the first screen, and also scrolls forward 10 lines at a time.