info processes info files, which are files in a special format, (often generated 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
To follow a cross reference, the cursor can be moved over a link (a word preceded by a *) and enter pressed.
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.