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In reading some the questions I find some commands I am not familiar with. I will run a man page on the command and reference the other questions entry to get a better understanding of the command. One was about using chkconfig. Sometimes the command line I reference has a switch that is not referenced in the man page. My question is am I missing something or is there an additional set of information that references more than the man page?

Here is an example:

chkconfig --level 3 squid off

--level is not listed in the man page. Using the man I would've used chkconfig --edit and worked it that way. Clearly using --level would be the better choice in this instance but it is not listed as a choice in the man page.

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up vote 4 down vote accepted

Sometimes you can find more help with chkconfig --help, info chkconfig, or apropos chkconfig.

On this, if you compare the man page for chkconfig on Ubuntu with any other, you'll see that the --level switch seems to have been replaced with the --set switch. While chkconfig on Ubuntu may still use the --level switch, it is not given in the man page, or it is an alias to the --set switch. (The Ubuntu-native equivalent is the update-rc.d command.)

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Manpages are created by developers. If they add a new feature, it's possible that they forget to update the manpages. The nice thing about open source applications is that you can take a look in the source itself. In the case of chkconfig, you can get the source from You do not have to understand the language fully, but it can give you an idea. The following part looked interesting to me, and is retrieved from chkconfig_11.0-79.1-2.tar.gz; chkconfig:

sub usage {
  print <<EOF;
        chkconfig -A|--allservices              (together with -l: show all services)
        chkconfig -t|--terse [names]            (shows the links)
        chkconfig -e|--edit  [names]            (configure services)
        chkconfig -s|--set   [name state]...    (configure services)
        chkconfig -l|--list [--deps] [names]    (shows the links)
        chkconfig -c|--check name [state]       (check state)
        chkconfig -a|--add   [names]            (runs insserv)
        chkconfig -d|--del   [names]            (runs insserv -r)
        chkconfig -h|--help                     (print usage)
        chkconfig -f|--force ...                (call insserv with -f)

        chkconfig [name]           same as chkconfig -t
        chkconfig name state...    same as chkconfig -s name state


if (!GetOptions('list|l'   => \&addmode,
                'terse|t'  => \&addmode,
                'add|a'    => \&addmode,
                'del|d'    => \&addmode,
                'edit|e'   => \&addmode,
                'help|h'   => \&addmode,
                'set|s'    => \&addmode,
                'check|c'  => \&addmode,
                'level=s'  => \$level,
                'force|f'  => \$force,
                'allservices|A'  => \$allservices,
                'deps'     => \$printdeps
   )) {
  exit 1;

As user4124 already mentioned, chkconfig is not a default command from Ubuntu, but originated from Redhat. Ubuntu uses init scripts (man 5 init). Ubuntu's chkconfig manpage is written by someone from SUSE (see the Author section). The Redhat version of the manpage is written by a Redhat developer.

Again note that manpages are written by humans. The Internet often contains more extensive guides on commands.

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You may try info, this will at times give more information than man, as to whether there will be more information on the specific command you would have to check, it is just useful to note that there is another command that gives information about applications and this information is sometimes different, so there may be something there that is missing from the other, as implied, info will at times just use the man pages when it does not have its own.

Example of difference:

man uniq gives less than info uniq

In fact at the end of the man page it says this:

info coreutils 'uniq invocation'

should give you access to the complete manual

Example of the same, In your case:

man chkconfig same as info chkconfig

The thing here is that you are not just interested in the one command chkconfig so you can use info just to see if you get useful pertinent additional information over the man pages on other commands of interest.

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Sometimes you will also find useful additional informations in /usr/share/doc.

Documentation in the info files can be searched for a string in case you don't know the file description needed to invoke the info command:

info -k 'searchstring'
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Happy searching :) – Lekensteyn Jan 26 '11 at 14:59

There might be some information missing from man pages though I would expect these are rare. What you need is a way to search across all the help and man pages.

Click on System » Help and Support and then perform a search.

It is important to note that chkconfig is not a default command of Ubuntu.

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