Arbitrary documentation inside Emacs buffer

With no doubt Emacs is an incredibly pertinent tool for software development. It contains all necessary functions out of the box, easily customizible by its open source nature and in charge to expel the lion's share of headache during casual programmer's tasks.

But during development process it is extremely useful to take in hands all sorts of documentation:

• about Emacs itself;
• about the particular programming language;
• about some useful framework;
• etc.

The most admirable feature of old open source products is their contemporary state. Each one have a large history of improvements, thus, nowadays most of the obvious questions have been successfully resolved earlier. All that remains to do is just to study documentation and utilize the maximum of useful features.

It's sensible to allocate all existing documentation in a share directory and that is:

ls -la /usr/share/info/

total 1084
drwxr-xr-x   5 root root   4096 Jul 16 18:40 .
drwxr-xr-x 297 root root  12288 Jul 11 17:16 ..
-rw-r--r--   1 root root 218669 Feb 22 14:23 coreutils.info.gz
-rw-r--r--   1 root root  61097 Jan 10  2017 diffutils.info.gz
-rw-r--r--   1 root root  12250 Jul 16 18:44 dir
-rw-r--r--   1 root root    781 Jul 16 17:52 dir.old
drwxr-xr-x   2 root root   4096 Jul 16 18:04 emacs-25
-rw-r--r--   1 root root  92043 Feb 18 17:37 find.info.gz
-rw-r--r--   1 root root  23649 Feb 18 17:37 find-maint.info.gz
-rw-r--r--   1 root root  14730 Feb 14 02:29 gnupg-card-architecture.png
-rw-r--r--   1 root root  90906 Feb 14 02:29 gnupg.info-1.gz
-rw-r--r--   1 root root  57247 Feb 14 02:29 gnupg.info-2.gz
-rw-r--r--   1 root root   2761 Feb 14 02:29 gnupg.info.gz
-rw-r--r--   1 root root  36868 Feb 14 02:29 gnupg-module-overview.png
-rw-r--r--   1 root root  28572 Jan 23 20:18 grep.info.gz
-rw-r--r--   1 root root  30648 Feb 11 17:09 grub-dev.info.gz
-rw-r--r--   1 root root  87920 Feb 11 17:09 grub.info.gz
-rw-r--r--   1 root root  14828 Mar 14  2016 gzip.info.gz
-rw-r--r--   1 root root  16206 Jan 11  2017 nano.info.gz
drwxr-xr-x   2 root root   4096 Jul 16 18:42 python3.4
-rw-r--r--   1 root root  24906 May 15 23:00 rluserman.info.gz
drwxr-xr-x   2 root root   4096 Jul 16 18:27 scrapy
-rw-r--r--   1 root root  52265 Feb  4 17:16 sed.info.gz
-rw-r--r--   1 root root   2407 Mar  6 00:13 spd-say.info.gz
-rw-r--r--   1 root root  58177 Mar  6 00:13 speech-dispatcher.info.gz
-rw-r--r--   1 root root  32815 Mar  6 00:13 ssip.info.gz
-rw-r--r--   1 root root   5323 Jul 21  2015 time.info.gz
-rw-r--r--   1 root root  69925 Mar 18 16:12 wget.info.gz

UNIX innate utility install-info:

install-info --version

install-info (GNU texinfo) 6.3

Copyright (C) 2016 Free Software Foundation, Inc.
License GPLv3+: GNU GPL version 3 or later <http://gnu.org/licenses/gpl.html>
This is free software: you are free to change and redistribute it.
There is NO WARRANTY, to the extent permitted by law.

There are several lists which define them:

After all these manipulations desired info should appear at Emacs *info* buffer.

• C-h i
• C-s python