What is GNU Info for?

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I understand what GNU Info is and how to use it, but what is it for? Why does it exist in parallel to the man pages? Why not write detailed man pages rather than provide a separate utility?

edited May 29 '13 at 17:06

Kyle Jones

11.5k13048

asked May 29 '13 at 14:40

johntait.org

5832717

3

texinfo file can do a lot more the groff macros.
– jordanm
May 29 '13 at 14:45

14

It's got one advantage over man pages: "hyperlinks". The rest are disadvantes, starting with Not Invented Here Syndrom, funny key bindings, hassle of dir maintenance and many more.
– Jens
May 29 '13 at 21:59

4

Use info --vi-keys to make info's keybindings feel more familiar. You can also use less with info to make it feel just like man: info --subnodes -o - $1 | less. You do lose some text formatting this way though.
– user26112
Jun 15 '13 at 11:12

1

Alternatively, point your browser at gnu.org/manual. (Using Vimperator/Vrome is optional.)
– nwk
Mar 9 '14 at 21:21

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up vote
58
down vote

favorite

I understand what GNU Info is and how to use it, but what is it for? Why does it exist in parallel to the man pages? Why not write detailed man pages rather than provide a separate utility?

edited May 29 '13 at 17:06

Kyle Jones

11.5k13048

asked May 29 '13 at 14:40

johntait.org

5832717

3

texinfo file can do a lot more the groff macros.
– jordanm
May 29 '13 at 14:45

14

It's got one advantage over man pages: "hyperlinks". The rest are disadvantes, starting with Not Invented Here Syndrom, funny key bindings, hassle of dir maintenance and many more.
– Jens
May 29 '13 at 21:59

4

Use info --vi-keys to make info's keybindings feel more familiar. You can also use less with info to make it feel just like man: info --subnodes -o - $1 | less. You do lose some text formatting this way though.
– user26112
Jun 15 '13 at 11:12

1

Alternatively, point your browser at gnu.org/manual. (Using Vimperator/Vrome is optional.)
– nwk
Mar 9 '14 at 21:21

add a comment |

up vote
58
down vote

favorite

I understand what GNU Info is and how to use it, but what is it for? Why does it exist in parallel to the man pages? Why not write detailed man pages rather than provide a separate utility?

edited May 29 '13 at 17:06

Kyle Jones

11.5k13048

asked May 29 '13 at 14:40

johntait.org

5832717

I understand what GNU Info is and how to use it, but what is it for? Why does it exist in parallel to the man pages? Why not write detailed man pages rather than provide a separate utility?

man history gnu info

edited May 29 '13 at 17:06

Kyle Jones

11.5k13048

asked May 29 '13 at 14:40

johntait.org

5832717

edited May 29 '13 at 17:06

Kyle Jones

11.5k13048

asked May 29 '13 at 14:40

johntait.org

5832717

edited May 29 '13 at 17:06

Kyle Jones

11.5k13048

edited May 29 '13 at 17:06

Kyle Jones

11.5k13048

edited May 29 '13 at 17:06

Kyle Jones

11.5k13048

asked May 29 '13 at 14:40

johntait.org

5832717

asked May 29 '13 at 14:40

johntait.org

5832717

asked May 29 '13 at 14:40

johntait.org

5832717

3

texinfo file can do a lot more the groff macros.
– jordanm
May 29 '13 at 14:45

14

It's got one advantage over man pages: "hyperlinks". The rest are disadvantes, starting with Not Invented Here Syndrom, funny key bindings, hassle of dir maintenance and many more.
– Jens
May 29 '13 at 21:59

4

Use info --vi-keys to make info's keybindings feel more familiar. You can also use less with info to make it feel just like man: info --subnodes -o - $1 | less. You do lose some text formatting this way though.
– user26112
Jun 15 '13 at 11:12

1

Alternatively, point your browser at gnu.org/manual. (Using Vimperator/Vrome is optional.)
– nwk
Mar 9 '14 at 21:21

add a comment |

3

texinfo file can do a lot more the groff macros.
– jordanm
May 29 '13 at 14:45

14

It's got one advantage over man pages: "hyperlinks". The rest are disadvantes, starting with Not Invented Here Syndrom, funny key bindings, hassle of dir maintenance and many more.
– Jens
May 29 '13 at 21:59

4

Use info --vi-keys to make info's keybindings feel more familiar. You can also use less with info to make it feel just like man: info --subnodes -o - $1 | less. You do lose some text formatting this way though.
– user26112
Jun 15 '13 at 11:12

1

Alternatively, point your browser at gnu.org/manual. (Using Vimperator/Vrome is optional.)
– nwk
Mar 9 '14 at 21:21

texinfo file can do a lot more the groff macros.
– jordanm
May 29 '13 at 14:45

It's got one advantage over man pages: "hyperlinks". The rest are disadvantes, starting with Not Invented Here Syndrom, funny key bindings, hassle of dir maintenance and many more.
– Jens
May 29 '13 at 21:59

Use info --vi-keys to make info's keybindings feel more familiar. You can also use less with info to make it feel just like man: info --subnodes -o - $1 | less. You do lose some text formatting this way though.
– user26112
Jun 15 '13 at 11:12

Alternatively, point your browser at gnu.org/manual. (Using Vimperator/Vrome is optional.)
– nwk
Mar 9 '14 at 21:21

add a comment |

5 Answers
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up vote
59
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accepted

GNU Info was designed to offer documentation that was comprehensive, hyperlinked, and possible to output to multiple formats.

Man pages were available, and they were great at providing printed output. However, they were designed such that each man page had a reasonably small set of content. A man page might have the discussion on a single C function such as printf(3), or would describe the ls(1) command.

That breaks down when you get into larger systems. How would you fit the documentation for Emacs into man pages? An example of the problem is the Perl man page, which lists 174 separate man pages you can read to get information. How do you browse through that, or do a search to find out what && means?

As an improvement over man pages, Info gave us:

The ability to have a single document for a large system, which contains all the information about that system. (versus 174 man pages)

Ability to do full-text search across the entire document (v. man -k which only checks keywords)

Hyperlinks to different parts of the same or different documents (v. The See Also section, which was made into hyperlinks by some, but not all, man page viewers)

An index for the document, which could be browsed or you could hit "i" and type in a term and it would search the index and take you to the right place (v. Nothing)

Linear document browsing across concepts, allowing you read the previous and next sections if you want to, either by mouse or keystroke (v. Nothing).

Is it still relevant? Nowadays most people would say "This documentation doesn't belong in a manpage" and would put it in a PDF or would put it up in HTML. In fact, the help systems on several OSes are based on HTML. However, when GNU Info was created (1986), HTML didn't exist yet. Nowadays texinfo allows you to create PDF, Info, or other formats, so you can use those formats if you want.

That's why GNU Info was invented.

answered May 29 '13 at 20:53

Alan Shutko

1,4111011

6

man -K foo, with uppercase option, does a global full text search. Try man -K global-apropos - it finds the pages for man itself, in english, and in local language.
– Volker Siegel
Jul 25 '14 at 16:43

1

How do you find out what '&&' means?... you look in the index: "man perl", from there you see Overview, Tutorials, Reference Manual, Internals, Misc (books, community sources, license, change-logs(~40), language + platform specific docs. Of those, for '&&', I look in the Reference Section and see syntax, data and operators, as 1st 3 sections like most language ref-manuals. && looks like an op, so I look in the perlop manpage, and 2nd screen down lists all the operators. Compare that to figuring out keys for --vi-mode arg to 'info'... good luck.
– Astara
Jun 12 at 3:06

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up vote
39
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The reason the Info system was invented is necessity, but I guess "laziness, hubris and impatience" is an equally good explanation.

The point of the GNU project was to develop a freely modifiable and freely distributible operating system and tools. The traditional Unix man system was based on the nroff/troff document formatting system from Bell Labs, which was at the time commercial (non-free) software. Eventually that system was reverse engineered and a free replacement called groff was created, but that was several years after the GNU project started. So using the man system for GNU documentation before then would have required implementing a troff replacement, a huge undertaking.

Meanwhile GNU Emacs was the first big project of GNU and it required extensive documentation. Facing a mountain of work implementing the GNU system, Richard Stallman cast about for existing software that he could use in his system. TeX already existed and had powerful document formatting capabilities. Unlike nroff/troff, TeX was free to use and redistribute. Texinfo was created as a documentation system to leverage the power of TeX for printed manuals and GNU Emacs for processing and online documentation reading. The original Texinfo processor and Info document browser were both written in Lisp and ran inside Emacs. The standalone Texinfo utilities came several years later.

answered May 29 '13 at 16:21

Kyle Jones

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up vote
19
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As the Wikipedia page says, TeXinfo was designed as the official documentation of the GNU project by Richard Stallman. It is a set of macros on top of TeX, and was designed for writing software manuals. I think Stallman considered man pages inadequate for the task. Two advantages Texinfo has over man pages is that it is hyperlinked, and second, that it is, by design easy to convert into other formats.

ADDENDUM: While not strictly relevant to the question, note that man pages are still considered the standard documentation system on free Unix-like systems like those running atop the Linux kernel and also the various BSD flavors. For example, the Debian package templates encourage the addition of a man page for any commands, and also lintian checks for a man page. Texinfo is still not widely used outside the GNU project.

edited Feb 7 '15 at 5:15

answered May 29 '13 at 15:02

Faheem Mitha

22.6k1879134

2

+1 especially for the note about hypertext, which I think was a major reason to want to move away from the (then more than now) hardcopy-oriented man format.
– tripleee
May 29 '13 at 16:49

@ChristopherSchultz edited
– Faheem Mitha
Feb 7 '15 at 5:16

I am used to books for reference materials. I can read them cover-to-cover. If manuals and books are inadequate for writing documentation, computers and languages would never have been taught or learnt. In learningk most follow a progression from low->high knowledge with more complex topics building on simpler ones. Books are almost what every child learns from -- sequentially presented information. H-links are for focusing on random topics of interest: if expert & master of topic - you know what you want and links can take you there fast. For reference & learning, links are a poor fit.
– Astara
Jun 12 at 3:21

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up vote
7
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From a practical view, info is the most detailed of three levels of reference documentation:

The three levels are usually increasing in detail:

--help as a common command option - a short usage summary,
man - the classic man pages, a quick reference, and
info - a more detailed, GNU-speciffic manual - the full, official documentation.

If an info page is not available, the man page usually contains the full documentation.

Note that the man page contains exactly the same information like the --help output for many commands from GNU coreutils - for example ls;

Compare ls --help and man ls to see that the difference is only in formating.

The default info viewer is info.

There are more comfortable alternatives, like for the terminal pinfo, of for the GUI konqueror:

pinfo ls

konqueror info:ls

edited Oct 8 '14 at 12:04

answered Jul 29 '14 at 3:46

Volker Siegel

10.7k33258

Well, you are thrifty, I'll give you that.
– mikeserv
Jul 29 '14 at 4:36

@mikeserv I did not find the sub-answer include feature. ;)
– Volker Siegel
Jul 29 '14 at 12:04

hmmm... very interesting, except that you forget to mention help as a command for builtin bash commands, and apropos and whatis as man with options for there practical use.
– user171470
May 27 '16 at 9:08

A hyper-linked reference is not a manual or book. A wiki? maybe, but manuals never come with hyperlinks in the off-line world. They come with references (see chapter 38), but they aren't good to learn from. Having recently read through the newer C++ book, I can agree it uses forward and backward references if you want more info about a topic that will be covered later. Once you've read the book, those references can be a great aid in finding things. But for someone new to a complex program? I'll prefer a book over a linked HTML or info page every time.
– Astara
Jun 12 at 3:26

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up vote
1
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1 - advanced, but lightweight technology

Man pages are flat.

info is a tree.

Both remain text based, so they can be used during low level system development, (unlike http, which requires a full blown GUI and browser before you can use it.)

This is also useful because linux can run on many low resource machines, for example, the stuff that runs on my Arduino from Atmel is found in info.

(History: info is similar to gopher, if you remember that. It was what we had just before we all moved into GUI OS's, and the the world wide web exploded. I remember that gopher worked pretty good for finding information, and it was fast and simple. It was easily expandable, fully text based, and fast.)

Man pages can't have operable hyperlinks. (It's just not possible in this technology.)

info can and does have many operable links from node to node, or from node to leaf, making it much easier to navigate big manuals quickly.

2 - contains content not found in man pages

Many standard packages also have a sister -doc package. Often this content is then found only inside info.

These documentation packages add booklets inside info, with sections, and sub-sections. In info lingo, these are called nodes, and nodes can contain other nodes in a tree structure.

There are commands to climb around the tree, here are some examples:

up a section, e.g. from section 2.1 to section 2

next section (i.e. move along branch tips from page to page), e.g. from Section 2, to Section 2.1, and (assuming there is no Section 2.2), onwards to Section 3

right a section, e.g. from Section 2 directly to Section 3, skipping section 2.1

If you're reading and you scroll down line by line, then you'll visit all sections of each booklet.

Important commands

l - go back - Lower case 'L', as in last. It's like the back button on your web browser. - Go back to the last node seen in this window (initially we only have one window). Wow, we can split the document window in half too!

d - my people - Go to the main 'directory' node. - This is the top of the INFO tree. Contains links to the families:

t - my family - Go to the top node of this document. - Generally the table of contents

u - my parent - Go up one level. e.g. go from Section 2.1, to Section 2.

n - my siblings - Go to the next node on this level. e.g. section 2 -> section 3 (not 2.1)

p - my siblings - Go to the previous node on this level. e.g. section 3 -> section 2

] - my children - Go to the next node in the document, e.g. section 2 -> section 2.1

[ - my children - Go to the previous node in the document, e.g. section 2.1 -> section 2

I also didn't really understand why I would want to use info. I had previously dabbled in it, and at first found it old-school. But because I needed some more information for an autoconf project, and it was suggested to me that this is where that documentation was, I took another look recently.

The first thing I had to do was to figure out how to navigate better. I found the help given by H almost unhelpful. That was until I noticed that I could scroll down into this help, ..but then there was too much confusion.

So I copied this help and pasted it together into a Gnote, and began to try to understand how info worked.

As I learned more, I rewrote their help for myself. I wanted to know what they full range of commands were, and how they were categorized.

I noticed that many of the key-strokes were duplicated, with 2 or 3 ways to execute a given command. I also noticed that this all looked very much like emacs.

Here is my cheat sheet of info commands:

HELP - info - commands

#####################################################################################################################################################
Short list - 'basic' Info command keys (see below for full list)

 C-g Cancel the current operation.
 H Close this help window. (toggle help window)
 q Quit Info altogether.

 h Invoke the Info tutorial.


 Move in this node
 Up Move up one line.
 Down Move down one line.


 PgUp Scroll backward one screenful. - also backspace
 PgDn Scroll forward one screenful. - also space

 Home Go to the beginning of this node.
 End Go to the end of this node.

 TAB Skip to the next hypertext link.

 / Search forward for a specified string.
 } Search for next occurrence.
 Search for previous occurrence.

 Move to other nodes
 RET Follow the hypertext link under the cursor.

 1...9 Pick the first...ninth item in this node's menu.
 0 Pick the last item in this node's menu.

 l Last in history. Go back to the last node seen in this window (initially we only have one window). (?? history)


 d Go to the main 'directory' node. my people
 the Info main menu - "This is the top of the INFO tree."

 t Go to the top node of this document. my family Generally the table of contents

 u Go up one level. my parent e.g. go from Section 2.1, to Section 2.

 n Go to the next node on this level. my siblings e.g. section 2 -> section 3 (not 2.1)
 p Go to the previous node on this level.

 ] Go to the next node in the document. my children e.g. section 2 -> section 2.1
 [ Go to the previous node in the document. (?siblings)


 m <name> Pick a menu item specified by name.
 f Follow a cross reference specified by name.
 g Go to a node specified by name.

 i Search for a specified string in the index (if there is an index), and select the node referenced by the first entry found.

 I Synthesize menu of matching index entries. ???




#####################################################################################################################################################
Full list - of commands available in Info windows:

Notes: 
 M- (meta) is Alt; (also you can use an Esc prefix instead of meta -hwj)
 M-C- means hold both Ctrl and Alt down at same time
 * Basic commands (listed above)



 HELP
* H (get-help-window) Toggle display of help message
* h (get-info-help-node) Visit Info node '(info)Help' (this gets: man info )


 CANCEL
* C-g C-x C-g M-C-g (abort-key) Cancel current operation (?? esc)

* q C-c (quit) Quit using Info
 C-x C-c (quit) Quit using Info


 WINDOWS
 C-l (redraw-display) Redraw the display

 x C-x 0 (delete-window) Delete the current window
 C-x 1 (keep-one-window) Delete all other windows (leaving 1)

 C-x 2 (split-window) Split the current window (into 2)
 C-x t (tile-windows) Divide the available screen space among the visible windows

 C-x ^ (grow-window) Grow (or shrink) this window

 C-x o (next-window) Select the next window (other)

 C-x C-b (list-visited-nodes) Make a window containing a menu of all of the currently visited nodes

 C-x w (toggle-wrap) Toggle the state of line wrapping in the current window

 VIEW OTHER FILE
 C-x C-f (view-file) Read the name of a file and select it
 C-x C-v (view-file) Read the name of a file and select it


 SCROLL
 C-v (scroll-forward-page-only) Scroll forward in this window staying within node ('v' looks like a down arrow)
 M-v (scroll-backward-page-only) Scroll backward in this window staying within node (meta-v is the reverse, or up arrow)

* PgDn SPC (scroll-forward) Scroll forward in this window (at end moving to next node??)
* PgUp DEL C-h (scroll-backward) Scroll backward in this window (at end moving to next node??) (DEL = Backspace or Del)

 M-C-v ESC PgDn (scroll-other-window) Scroll the other window
 ESC PgUp (scroll-other-window-backward) Scroll the other window backward


 CURSOR MOVEMENT (within a 'node' / page)
 Right C-f ( forward-char) Move forward a character
 Left C-b (backward-char) Move backward a character

 M-b (backward-word) Move backward a word
 M-f ( forward-word) Move forward a word

 C-a (beginning-of-line) Move to the start of the line
 C-e (end-of-line) Move to the end of the line


* Up C-p (prev-line) Move up to the previous line
* Down C-n (next-line) Move down to the next line

 M-r (move-to-window-line) Move the cursor to a specific line of the window

* Home b ESC < (beginning-of-node) Move to the start of this node
* End e ESC > (end-of-node) Move to the end of this node


 SEARCHING
 / (search) Read a string and search for it
 s (search) Read a string and search for it
 ? (search-backward) Read a string and search backward for it

 R (toggle-regexp) Toggle the usage of regular expressions in searches

 S (search-case-sensitively) Read a string and search for it case-sensitively

* C-x n (search-next) Repeat last search in the same direction
* C-x N (search-previous) Repeat last search in the reverse direction


 C-s (isearch-forward) Search interactively for a string as you type it
 C-r (isearch-backward) Search interactively for a string as you type it


 M-/ (tree-search) Search this node and subnodes for a string.

 M- (tree-search-next) Go to next match in Info sub-tree
 M-improve this answer

edited Feb 7 '15 at 5:15

answered May 29 '13 at 15:02

Faheem Mitha

22.6k1879134

answered May 29 '13 at 15:02

Faheem Mitha

22.6k1879134

answered May 29 '13 at 15:02

Faheem Mitha

22.6k1879134

2

+1 especially for the note about hypertext, which I think was a major reason to want to move away from the (then more than now) hardcopy-oriented man format.
– tripleee
May 29 '13 at 16:49

@ChristopherSchultz edited
– Faheem Mitha
Feb 7 '15 at 5:16

I am used to books for reference materials. I can read them cover-to-cover. If manuals and books are inadequate for writing documentation, computers and languages would never have been taught or learnt. In learningk most follow a progression from low->high knowledge with more complex topics building on simpler ones. Books are almost what every child learns from -- sequentially presented information. H-links are for focusing on random topics of interest: if expert & master of topic - you know what you want and links can take you there fast. For reference & learning, links are a poor fit.
– Astara
Jun 12 at 3:21

up vote
1
down vote

1 - advanced, but lightweight technology

Man pages are flat.

info is a tree.

Both remain text based, so they can be used during low level system development, (unlike http, which requires a full blown GUI and browser before you can use it.)

This is also useful because linux can run on many low resource machines, for example, the stuff that runs on my Arduino from Atmel is found in info.

Man pages can't have operable hyperlinks. (It's just not possible in this technology.)

info can and does have many operable links from node to node, or from node to leaf, making it much easier to navigate big manuals quickly.

2 - contains content not found in man pages

Many standard packages also have a sister -doc package. Often this content is then found only inside info.

These documentation packages add booklets inside info, with sections, and sub-sections. In info lingo, these are called nodes, and nodes can contain other nodes in a tree structure.

There are commands to climb around the tree, here are some examples:

up a section, e.g. from section 2.1 to section 2

next section (i.e. move along branch tips from page to page), e.g. from Section 2, to Section 2.1, and (assuming there is no Section 2.2), onwards to Section 3

right a section, e.g. from Section 2 directly to Section 3, skipping section 2.1