Linux info command
Linux Command Encyclopediainfo is a powerful documentation reading tool in the Linux system. It provides more detailed and structured help documentation than the man command. info documents organize content in the form of hypertext links, making them especially suitable for browsing complex software documentation.
Differences between info and man
| Feature | info command | man command |
|---|---|---|
| Document structure | Hypertext links, clearly hierarchical | Linear text, single-page display |
| Content depth | More detailed, includes tutorials and examples | Concise, mainly reference manual |
| Navigation method | Supports node jumping and searching | Can only scroll up and down |
| Applicable scenarios | Documentation for complex software (GCC, Emacs, etc.) | Quickly look up command usage |
Basic syntax
info [选项] [菜单项目...]
Common options
| Option | Description |
|---|---|
-a |
Use all matching documents |
-d |
Add directory to INFOPATH |
-f |
Specify the info file to access |
-n |
Specify the first node to access |
-o |
Output to specified file |
Using the info system
Starting info
info
Running it without arguments displays the top-level directory of the info system.
Viewing documentation for a specific command
info coreutils
This will open the GNU coreutils documentation.
Navigation commands
After entering the info interface, you can use the following shortcut keys to navigate:
Basic navigation
| Shortcut key | Function |
|---|---|
h |
Display help |
? |
Display command summary |
q |
Exit info |
SPACE |
Page down |
DEL |
Page up |
Node navigation
| Shortcut key | Function |
|---|---|
n |
Next node |
p |
Previous node |
u |
Up one node |
m |
Select menu item |
l |
Return to the previously viewed node |
Search function
| Shortcut key | Function |
|---|---|
s |
Search |
i |
Index search |
, |
Find next match |
Practical examples
Example 1: View the info documentation for the ls command
info ls
This will display the detailed documentation for the ls command, including:
- Command syntax
- All option descriptions
- Usage examples
- Related command links
Example 2: Search for specific content in the documentation
- Open the info document
- press
sKey - Enter a search term such as "permission"
- Press Enter to start searching
- Use
,Find next match
Creating custom info documents
1. Write a texinfo file
input texinfo @setfilename mycommand.info @settitle My Command Manual @node Top @top My Command This is the top node of my command documentation. @menu * Introduction:: Introduction to my command. * Usage:: How to use my command. @end menu @node Introduction @chapter Introduction This command does something useful. @node Usage @chapter Usage Here's how to use it...
2. Compile it into info format
makeinfo mycommand.texi
3. Install the info document
install-info mycommand.info /usr/share/info/dir
Advanced tips
Viewing info in Emacs
Emacs has a built-in powerful info browser:
M-x info
Printing info documents
info --subnodes -o output.txt bash
Setting the default info browser
export INFO_COMMAND="pinfo"
FAQ
Q: Why do some commands not have info documentation?
A: Not all software provides documentation in info format; traditional Unix commands usually only have man pages.
Q: How to update the info database?
A: Runsudo update-info-dircan update the info directory database.
Q: Where are info documents stored?
A: Usually in/usr/share/info/directory, in.info.gzformat.
Other extensions