The info command

info is the GNU hypertext documentation browser program.

Just run info with no args, and you'll get some helpful usage instructions right at the top of the screen. Hit ? for more help. Note that the commands used inside info are often similar to GNU Emacs commands.

A single Info doc often consists of a number of nodes arranged in a tree structure:

 Top
  |\
  | \
  |  \
chp1  chp2
 |     |  \
 |     |   \
 |     |    \
sec1  sec1  sec2   (sections)
      /|\
     / | \
    /  |  \
  ss1 ss2 ss3      (subsections)

A node is one page (which might be longer than your terminal window) of documentation. Many nodes have "menus" on them -- lines that start with a '*', which point to sub-nodes of the current node. You can scroll the cursor down to them, and hit RET to follow them, or else you can hit m and type the menu title then RET.) Menus are like hyperlinks on a web page that direct you to subsections of the current section.

Nodes have an order to them (left-to-right in the diagram above). You can hit n to go to the "next" one (if it has a next one), and p to go back to the previous one (if there is a previous one). You might think of nodes going left-to-right, whereas you "descend" down into a node (to a "lower level" (i.e. a subtopic)) by following a menu item. Use u to come back up.

You only use n and p to traverse nodes at the same level that are under the same parent node. You use menus to descend down to lower levels (as in: chapter --> topic, topic --> subtopic, subtopic --> sub-subtopic).

Use SPACE and BACKSPACE to move through a long node (PgUp/PgDn work too, as do C-v and M-v). If you keep hitting SPACE, it takes you to the next node. BACKSPACE will eventually get you to the previous node.

You can hit q at anytime to quit info. For commands that expect input, you can always hit C-g to cancel.

Summing those up:

• n -- next node on same level, under same parent node
• p -- previous node on same level, under same parent node
• u -- up to the parent node
• SPC -- scroll down, then on to the following node
• BACKSPACE -- scroll up, then back to the earlier node
• q -- quit info

Here's a few more of the essentials:

• l -- go back to where you just were (last node visited). Even puts your cursor where it was. :)
• 0 ... 9 -- hitting a number whisks you off to that section number. It's very handy when you know you want to get to a specific section, like say 2.7.4, but don't recall off-hand exactly what the menu names for each of those steps are. You'd just hit 274 and you'd be there. :)
• b -- go back to the beginning of the current node.
• t -- go to the top node of the particular manual you're reading.
• d -- takes you to the top-level info page.
• TAB -- go to next hyperlink/menu. M-TAB for previous.
• RET -- when cursor is on a menu or xref, follow that link.
• m menu_name -- choose a given menu by name.
• f xref_name -- follow a cross-reference, by name. Like m for menus.
• Use f ? to get a list of available xrefs in the current node.
• r -- follow the next cross reference? XXX
• i -- Hit i to search the index node(s) for this info doc, if there is one available. Hit , (comma) to go to the next search result.
• s -- search for a string starting on the current node. To find again, hit s then RET (the default is to search for the last term you searched for). Note, find-again will take you node-to-node through the document. If you go one too far, hit l to go back.
• ] -- like SPC, but skips past the rest of the current node and jumps straight to the next one. [ is like BACKSPACE in the same way.

Don't forget, when info prompts you for something (like, after you hit m), you have case-insensitive autocomplete available -- just hit TAB to get a match.

A "cross-reference" looks like so: *Note Foo: Help-Foo. It's just another hyperlink. Here, the name of the cross-ref is "Foo" and it leads to the node named "Help-Foo". Just remember that menus are for subtopics, but cross refs are for linking to other nodes that you can't get to directly with n, p, and menus -- maybe even to nodes in another manual.

A given info doc may or may not have one or more index nodes. While looking at any node, you can hit 'i' and search that doc's index. You can navigate to the index node just like any other node -- if there is one, it's usually the last one in the Top node of the manual you're reading.

C-h i m emacs RET