Only five lines are displayed: Those that aren't empty, and aren't comments. At the bottom of the screen, you can see that less is displaying an ampersand symbol before its usual "(END)" marker to tell you that you're looking at a filtered version.

Notices where this attachment appears

1. Embed this notice
   scy (scy@chaos.social)'s status on Thursday, 19-Sep-2024 00:19:09 JST scy

   Suppose you're using less(1) to view a config file that has lots of commented-out explanations and defaults:

   less /etc/ssh/ssh_config

   It's hard to really see which lines are in effect and which are just comments, especially without syntax highlighting.

   But! You can use less's filtering capabilities to only display lines that start with a character that's not a hash symbol. Type "&" and enter a regular expression, then hit return. For example:

   &^[^#]

   Enter an empty regex to stop filtering.