How to efficiently search Info documentation?

Question

I was looking for documentation on tr program. As you would imagine the combination of characters t and r happens fairly often in English language... Although I was sure about the name, I wasn't sure about the name of the section it belongs to, so I had to display all nodes and try searching for something like tr or tr( and so on.

Isn't there a better way to do it?

Answer 1

Hmm... I can only guess that the following isn't happening for you; however nodes for individual programs really ought to be listed in the top-level directory, and hence show up when you type M-x info RETd, from where you can simply use m tr RET.

However if you're searching for something which isn't in any of the directory files, the only convenient thing I know of is M-x info-apropos (which searches all of the indexes rather than the node titles).

And of course within a given manual you can use I to search its index, which is much faster than searching all of them.

Edit: This is tangential, but an excellent improvement in the upcoming Emacs 24.4 (currently undocumented in the NEWS file) is completion for Info node names in non-current manuals.

e.g. C-hig (elisp) TAB now provides completions for all the nodes in the elisp manual, even if you are not currently viewing that manual.

This is an extremely welcome change!

Answer 2

Icicles can help here. All Info commands that use completion let you take advantage of Icicles completion features. This includes apropos completion -- regexp matching, which means that you essentially get on-the-fly info-apropos behavior, among other things. And it includes progressive completion, which means you can add additional patterns to progressively narrow your search. When completing you can sort the candidates in various ways, including sorting Info nodes in book order for g.

g (icicle-Info-goto-node) lets you search both node names and node contents at the same time: Your minibuffer input can contain a second search pattern that is matched against the node contents. The completion candidates are those whose names match the node-name pattern you type (if any) and the node-content pattern you type (if any). Each pattern is a regexp (which includes substring matching as a simple case).

See Icicles Info Enhancements for more information.