Command "tree" vs "tree -R"

Question

So I'm asking myself why there is the "-R" argument for the "tree" command.

The manual says "-R Recursively cross down the tree each level directories ...", but I don't see any difference in the result between those two.

Answer 1

The -R option is only effective in HTML output mode, and is ignored if you don’t also specify a maximum display depth with the -L option.

tree -R -L 2 -H . -o tree.html

will output the tree to tree.html, and additionally generate subtrees every two levels in OOTree.thml files in each corresponding directory.