Use GNU info to Find, Read and Export Manuals

You will use the installed GNU info reader to find a manual, open a particular node and export useful documentation to a text file. This guide uses GNU texinfo 7.1, installed here as package info version 7.1-3build2. Allow about ten minutes. You need a shell and a readable Info document; none of the examples require elevated privileges.

infobrowser is an alias manpage for the same program and interface. The command itself is info.

1. Check the installed reader

Confirm which executable your shell will run, then check its version. These are read-only commands:

$ command -v info
/usr/bin/info
$ info --version
info (GNU texinfo) 7.1
$ dpkg-query -W -f='${Package} ${Version}\n' info
info 7.1-3build2

The version matters when comparing examples from another system. Option names and the general navigation model in this guide match the installed 7.1 manpage.

2. Open the top-level catalogue

Run info with no arguments to open the merged top-level directory of manuals:

$ info

This starts an interactive terminal reader. The screen is not ordinary shell output, so do not expect a prompt until you leave it. Press H inside Info for a summary of its key bindings. Space moves forwards and Backspace moves backwards in a document. Press q to leave the reader.

The most common distraction is treating every word on the screen as a shell command. Info is node-based: a manual is split into named sections, and menu entries or links move between those nodes.

3. Start at a named manual

Pass a menu item as the first non-option argument. For example, this opens the stand-alone Info manual:

$ info info-stnd

Likewise, info emacs requests the Emacs manual if it is installed. The name is looked up in the dir files along INFOPATH; it is not necessarily a file name that you can see in the current directory.

To see where a manual is stored without opening it, use --where:

$ info --where info
/usr/share/info/info-stnd.info.gz

Output varies with installed packages and local Info directories. If a manual is missing, check the spelling and then check whether its package is installed. A path printed by --where is useful evidence that the reader can locate that manual.

4. Jump to a node

Use -n or --node to select a node in the first manual you visit. This example opens the Files node in the Emacs manual:

$ info emacs -n Files

Some node names contain spaces or punctuation. Quote a complete node reference when necessary. The manpage also documents the parenthesised form:

$ info '(emacs)Files'

Those two examples are alternatives, not commands to run together. If the node is not found, inspect the manual's menu and use the exact displayed name. Do not guess a node from a web page written for another version.

5. Search all installed indices

Use -k or --apropos to search the indices of all available manuals:

$ info --apropos='copy'
"(gmp)Copying" -- Conditions for copying GNU MP
"(gmp)Copying" -- Copying conditions
"(gmp)Low-level Functions" -- mpn_copyd

The output depends on the manuals installed on your machine. If no files match, that is a valid result, not a prompt to alter INFOPATH. Try a shorter or more exact term, and confirm a relevant manual exists with info --where MANUAL.

--index-search=STRING goes directly to the node named by an index entry in the first visited Info file. This is more targeted than a broad catalogue search:

$ info --index-search='files' coreutils

Index wording is manual-specific, so a failed search does not prove that the subject is undocumented.

6. Export a node or manual

Use -o FILE or --output=FILE when you need plain text for a ticket, review or offline reading. This example exports the complete stand-alone Info manual:

$ info --subnodes --output=/tmp/info-stnd.txt info-stnd
$ sed -n '1,12p' /tmp/info-stnd.txt
File: info-stnd.info,  Node: Top,  Next: Stand-alone Info,  Up: (dir)

Stand-alone GNU Info

--subnodes recursively includes the menu items below the selected manual. Without it, output is limited to the selected nodes. The output file is overwritten if it already exists, so choose a new path or verify the destination first.

For one node, combine --file, --node and --output:

$ info --file=/usr/share/info/coreutils.info.gz --node='cp invocation' --output=/tmp/cp-invocation.txt
$ sed -n '1,10p' /tmp/cp-invocation.txt
File: coreutils.info,  Node: cp invocation,  Next: dd invocation,  Up: Basic operations

11.1 'cp': Copy files and directories

The exact text depends on the installed manual. The path in this example was verified with the local Info installation. These commands create or replace files under /tmp; remove them later if they contain material you no longer need. Do not export sensitive documentation to a shared directory without checking its permissions.

7. Use a local manual file

-f or --file tells Info to open a specific manual instead of searching the directory catalogue:

$ info --file=./foo.info

Replace ./foo.info with a real Info file. A relative path is resolved from the current directory, so check it with test -r ./foo.info && echo readable before opening it. This avoids the common error of passing a package name when you meant a local file.

8. Keep configuration changes out of a reading task

The reader has options that affect how it locates or interprets documents. -d DIR adds a directory to INFOPATH, and -v VAR=VALUE assigns an Info variable for the session. They do not install manuals or edit system configuration.

Use them only when you know the document layout you are troubleshooting. Start with info --where and an explicit --file path. Avoid changing a global shell profile merely because one manual is absent. There is no service restart or persistent change in this guide, and the exported files in /tmp can be deleted without affecting Info itself.