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``Red Hat Tips'' are documentation meant to help Red Hat users with specific tasks. Some of these documents are for new users, some are for advanced users. Hopefully each document will also be of help for both new and advanced users. If you have contributions to make, please send them to tech-sup@redhat.com. If you have changes that need to be made to individual Tips, send them to the author of that document.
This document is intended to help the user find help on his/her own system quickly and easily. Failing that, this document also contains pointers to very valuable information from other sources.
When you are looking for general help on commands and error messages, the best place to start is right on your system.
Most every command on your system has an associated ``man'' page. This
is documentation that you can get to instantly should you have questions
or problems. If you were having trouble with the command ls, you
could enter man ls. This will bring up the man page for ls.
The man page is viewed through the less program, so all of the
options to less will work while in a man page. Some important
key strokes are:
q to quitEnter to page down line by lineSpace to page down page by pageb to page back up by one page/ followed by a string and Enter to search for
a stringn to find the next occurance of the previous searchSometimes viewing man pages isn't too friendly on line. Providing you
have a working printer, you can print man pages as well. If you don't
have postscript printing capability and just want to print ASCII, you
can print man pages with man COMMAND | groff -mandoc -Tascii | lpr.
If you do have a postscript printer, you will probably want to print
with man COMMAND | groff -mandoc | lpr. In both of
those commands substitute ``COMMAND'' for the command you are trying
to get help for.
Also, sometimes things have more than one man page. Here is a table of what is located where:
Section Contents
------- ----------------
1 user commands
2 system calls
3 library calls
4 devices
5 file formats
6 games
7 miscellaneous
8 system commands
9 kernel internals
So, let's say that you want to see the man page for swapon. You
do man swapon. You will actually get the man page for the system
call swapon(2), which is the function you use in a C program to
turn swap on. Unless you are writing your own program to do it, this
probably isn't what you want. So, using the chart above, you can see
that what you want is probably a ``system command'' and is located
in section 8. You can then do man 8 swapon. All of this is because
man searches the man directories in order, and then returns when it
finds the first match.
You can also search the man pages for strings. You do this using
man -k string_to_search_for. This won't work, however, unless
the database is created. Under Red Hat, this gets done by a cron
job overnight. If you don't leave your system on overnight you
won't have the database. If that is the case, just run:
/usr/sbin/makewhatis /usr/man /usr/X11R6/man
Note: This must be done as root. Once you've done that, you could do
man -k swapon. That would return:
# man -k swapon
swapon, swapoff (2) - start/stop swapping to file/device
swapon, swapoff (8) - enable/disable devices and files for paging and swapping
swapon, swapoff (2) - start/stop swapping to file/device
swapon, swapoff (8) - enable/disable devices and files for paging and swapping
So you can see that there are pages in section 2 and 8 both referring to swapon (and swapoff in this case).
Many packages of software have READMEs and other documentation as part
of the source package. We have come up with a standard place to install
those documents for you so that you don't have to install the sources
to look at the documents. All of those documents are stored in subdirectories
of /usr/doc. The subdirectory depends on the package. Each package
that has extra documentation will create a directory called
packagename-version-releasenumber. For example, the tin package might
be version 1.22 and release number 2. The path to its documentation would
be /usr/doc/tin-1.22-2.
For the most part, the documents in this directory are ASCII. You can usually
for them with more filename or less filename.
This is nice, but what if you want to see if there is documentation for a specific command or file and you don't know the package it came from? It doesn't matter! You can simply do:
rpm -qdf /etc/sendmail.cf
This will report all the documentation from the package containing the
file /etc/sendmail.cf. Commands like this are covered more in
depth in the RPM-HOWTO, most likely available wherever you got this
document.
Also, what if it's a command you need help with and the man page isn't good? You could do something like:
rpm -qdf `which COMMAND`
Again, where ``COMMAND'' is the actual command you need help with. This will only work when the command is on your path.
Most of the contents of the Linux Documentation Project (LDP) are
available in /usr/doc on your system.
/usr/doc/HOWTO contains the ASCII versions of all the available
HOWTOs at the time we pressed the CD-ROM. They are gzipped, so you will
have to use gunzip to unzip them or you will have to use something
like zcat HAM-HOWTO.gz | more. The latter will work, but is
a bit less flexible than unzipping and then using more. It also
requires more disk space unless you re-gzip the document when done.
/usr/doc/HOWTO/mini contains the ASCII versions of all the
available mini-HOWTOs. They are not compressed and can be viewed
with more or less.
/usr/doc/HTML contains the HTML versions of all the HOWTOs and
the _Linux Installation and Getting Started_ guide. To view things
here, just use a WWW browser (like lynx or Mosaic). You
would do something like:
cd /usr/doc/HTML
lynx index.html
/usr/doc/FAQ contains ASCII version (and some HTML versions)
of some popular FAQs, including the RedHat-FAQ. All of them can be
viewed using more or less.
When you don't know the full name of a command or file, but need to
find it, you can usually find it with locate. locate uses
a database to find all files on your system. Normally, this database
gets built from a cron job every night. This won't happen, however,
if your machine isn't booted into Linux all the time. So, if that is
the case, you may occasionally want to run the following command:
/usr/bin/updatedb --prunepaths='/tmp /proc /mnt /var/tmp /dev'
You will need to be root on your system when doing that. That will allow
locate to work properly.
So, if you know you need to find all the ``finger'' files, you could run:
locate finger
It should return something like:
/usr/bin/finger
/usr/lib/irc/script/finger
/usr/man/man1/finger.1
/usr/man/man8/in.fingerd.8
/usr/sbin/in.fingerd
One thing to note, however, is that locate not only returns hits
based on file name, but also on path name. So if you have a
/home/djb/finger/ directory on your system, it would get returned
along with all files in the directory.
While man is the most ubiquitous documentation format, info
is much more powerful. It provides hypertext links to make reading
large documents much easier and many features for the documentation
writer. There are some very complete info documents
on various aspects of Red Hat (especially the portions from the GNU project).
To read info documentation, use the info program without
any arguments. It will present you with a list of available documentation. If
it can't find something, it's probably because you don't have the package
installed that includes that documentation. Install it with RPM and
try again.
If you're comfortable using emacs, it has a built in browser for info
documentation. Use C-h C-i to see it.
The info system is a hypertext based system. Any highlighted
text that appears is a link leading to more information. Use the Tab
key to move the cursor to the link, and press Enter to follow the
link. Pressing p returns you to the previous page, n moves you
to the next page, and u goes up one level of documentation. To
exit info, press C-x C-c (that's control-x followed by control-c).
The best way to learn how to use info is to read the info documentation
on it. If you read the first screen that info presents you'll be
able to get started.
If you can't find help for your problem on line and you have WWW access, you should see http://www.redhat.com/mailing-list.html. Here you can search the archives of the redhat-list. Most all questions have already been answered there.
If you've exhausted all options in finding help for your problem, you next best alternative is to ask for help on the Red Hat Mailing Lists. For the most up to date info, see http://www.redhat.com/mailing-list.html.
The request addresses for each of our lists is:
redhat-list-request@redhat.com
redhat-digest-request@redhat.com
redhat-announce-list-request@redhat.com
redhat-devel-list-request@redhat.com
rpm-list-request@redhat.com
axp-list-request@redhat.com
sparc-list-request@redhat.com
To subscribe, send mail to the address of the list you want to subscribe to with ``subscribe'' in the Subject line.
To unsubscribe, send mail to the address of the list you want to unsubscribe from with ``unsubscribe'' in the Subject line.
Then to send mail to the list, you just send it to the address above without the ``-request'' in the name. The only exception to this is the redhat-digest which is only a digest version the redhat-list. In that case the address is ``redhat-list@redhat.com''.
Another good source of help is the comp.os.linux hierarchy on USENET. If you are familiar with news, you should check it out. I won't go into using News here. There will be a ``Using News'' Tips document at some point to help with that.
This document is Copyright (C) 1996 by Red Hat Software. Redistribution of this document is permitted as long as the content remains completely intact and unchanged. In other words, you may reformat and reprint or redistribute only.