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Table of Contents
How to search and read Manpages efficiently
I hope this Howto can help some of you, although I'm aware that many of the readers are already familiar with this subject.
Searching for a Manpage
In order to search for information about anything in the manpages you can use one of the following commands:
apropos
man -k
whatis
apropos
is only an alias for man -k
; there is no difference between them. The difference between whatis
and the other commands is that whatis
searches for whole words whereas apropos
(or man -k
respectively) searches for parts of strings.
If you don't know how exactly a word, for example a command, is written, you can use apropos
. If you know exactly the word to search for, whatis
would be more efficient because it results in fewer lines of output.
Example
Searching for information about DHCP:
With the apropos
command:
markus@samsung:~$ apropos dhcp dhclient [] (8) - script - DHCP client network configuration script dhclient.conf [] (5) - DHCP client configuration file dhclient.leases [] (5) - DHCP client lease database dhcp [] (5) - eval - ISC DHCP conditional evaluation dhcp [] (5) - options - Dynamic Host Configuration Protocol options dhcpcd [] (8) - an RFC 2131 compliant DHCP client dhcpcd [] (8) - run-hooks - DHCP client configuration script dhcpcd.conf [] (5) - dhcpcd configuration file dhcpctl_initialize [] (3) - dhcpctl library initialization dhcpctl_initialize [] (3p) - dhcpctl library initialization dhcpd [] (8) - Dynamic Host Configuration Protocol Server dhcpd.conf [] (5) - dhcpd configuration file dhcpd.leases [] (5) - DHCP client lease database dnsmasq [] (8) - A lightweight DHCP and caching DNS server
With the whatis
command:
markus@samsung:~$ whatis dhcp dhcp [] (5) - eval - ISC DHCP conditional evaluation dhcp [] (5) - options - Dynamic Host Configuration Protocol options
For both commands, the search is case-insensitive!
Updating the ''whatis'' Database
The whatis
command has its own database. The manpages for any packages of the stock Slackware installation are already present in the database. This is also true if you upgrade such packages. But if you build your own packages from source, for example from SlackBuilds.org, the manpages for these packages are not yet present in the whatis
database. In order to update the database after installing new packages, Slackware provides the makewhatis
command. It has to be executed as root.
Please note that some other distributions use the mandb
command for this purpose.
The Sectioning of the Manpages
Don't confuse the sectioning of the manpages with the uniform structure of each manpage, this is described in the paragraph below.
The manpages are divided into eight different sections. Here is an extract from the manpage for the man
command.
MANUAL SECTIONS The standard sections of the manual include: 1 User Commands 2 System Calls 3 C Library Functions 4 Devices and Special Files 5 File Formats and Conventions 6 Games et. Al. 7 Miscellanea 8 System Administration tools and Deamons
If the manualpages for a topic are divided over different sections, one can pass the section number as an argument to the man
command.
Example
markus@samsung:~$ apropos man ... makecontext [] (3) - manipulate user context makedev [] (3) - manage a device number man [] (1) - format and display the on-line manual pages man [] (7) - macros to format man pages man [] (7) - pages - conventions for writing Linux man pages man.conf [] (5) - configuration data for man man2html [] (1) - format a manual page in html manuals with [] (7) - mdoc
Now if you want to read the manpage about “macros to format man pages” in section 7 you'll have to execute the following command:
man 7 man
The Structure of the Manpages
The manpages have (should have) all the same structure:
- Name
- Name of the command and a short description about it's function(s)
- Synopsis
- A short list of the options and the synopsis
- Description
- The detailed explanation of the command
- Options
- Detailed explanation of the commandline-options for the command
- Bugs
- Known Bugs
- Author
- The author(s) of the package and maybe the author of the manpage
- See also
- Advice for manpages about similar or related programs
If one searches for information about a subject rather than a single command the “see also” line is very interesting.
Searching within a Manpage
The reader for the manpages is the program less
. Its keybindings are very similar to the vi editor.
With /
one searches the document forward, with ?
backwards. With n
the cursor jumps to the next match. The -
key has no special meaning in the search patterns, so it is possible to search (for example) for the -k option with /-k
Example
Searching for the -h option in the manpage for the ls
command with /-h
gives us
-h, --human-readable with -l, print sizes in human readable format (e.g., 1K 234M 2G)
Navigation within a Manpage
Navigation is like in vi:
G
end of the manpagegg
first line of the mapagenG
nth line of the manpage
One can also set marks at a line of the manpage
ma
sets mark a in the current line'a
jumps to mark a in the manpage
Unfortunately these marks are lost when you leave the manpage (which is done with q).
Formatting a Manpage as a PDF-document
If you want to have a manpage as a PDF document you can use the command:
man -t ls | ps2pdf - > ls-manpage.pdf
which formats the manpage for the ls
command into a pdf document named “ls-manpage.pdf”.
Further Reading
For more information read the manpage for the man
command and read the manpages listed in “see also”.