Info allows to read info files, which are files in a special format info generated by texinfo program from a Texinfo source, and presents the documentation as a tree, with simple commands to traverse the tree and to follow cross references. For instance
n goes to the next page.
p goes to the previous page.
u goes to the upper page.
l goes to the last visited node
Moving the cursor over a link (a word preceded by a * ) and pressing the enter key follows a cross reference.
The C implementation of info was designed as the main documentation system of GNU based Operating Systems and was then ported to other Unix-like operating systems. However, info files had already been in use on ITSemacs.