Find previous searches in less command

To browse less search history (~/.lesshst by default, man less and LESSHISTFILE for more):

1. less a file, for example less ~/.lesshst
2. type / or ? to search forward or backward or & to show only matching lines (/!, ?! or &! for non-matching)
3. use up and down arrows ↑ and ↓ to browse the history, press Enter to choose one
4. n repeats the search, N in reverse direction

Use / to search forward. Use ? to search backward.

Use n for the next occurrence of the search item and N for prior occurrence. This works for both forward and backward searches.

And as pointed out in the comments if less history is enabled you can carry your search item across invocations of less.

man less and man lesskey for the details.