function f-tutorial.8 ()
{
white
clear
bold ; cyan
printf "\n\n\n"
echo "In Which We Get Everything We Want"
white ; echo
cat << EOWOOHOO

It's not obvious, but there are all kinds of goodies out there just
waiting to be installed...

One of the greatest strengths of Debian-based distributions of GNU/Linux
is the packaging system, and the policy that makes it work so well.

Here we begin to explore what can be done with the tools of this system.
It is an error to think that these are only about installing and removing
software. 

We can do all kinds of things with apt, aptitude and dpkg... dpkg in 
particular is useful for various configuration tasks, for example.

If you haven't used these tools before, you are in for some serious fun.
Installing is so automatic almost nothing needs to be done...

Ah, but you have to know the commands! The simplest ones are easy enough.

Read on!


EOWOOHOO

f-tutescape
echo ; cyan
printf "\n\n\n\n"
echo "The ADVANCED Package Tool."
white
cat <<EOAPT1

"apt" is an automatic (dare we say automagic?) tool for installing and removing
software. In GNU/Linux, binary software comes in "packages". This does not mean that 
everything required to install or remove an application is in one package, though.

In the grand UNIX tradition, the bits are often separate, but depend on each other
to work. If we had to figure out all the dependencies for installing things, we
would spend a *lot* of time searching for the bits needed. Indeed, until a few years 
ago that is essentially what we had to do. 

Packaging tools make the computer do the work for us.

Before apt there was dpkg - dpkg is still important: it is the system of packaging
and configuration tools at the lower level that apt and aptitude use. It is probably 
easier, though, to start with a general explanation of apt.

Rather than making the user search the Web for programs, most Linux distributions 
these days use collections of "packages" known as "repositories", stored on server
machines. This way, we can point our installation tools at the location of these
repositories and let the system do the searching and downloading, and the installation,
for us.

Let's take a look at how this works in practical terms...

First, let's see what the repository idea looks like.

EOAPT1
f-tutescape

clear
cyan ; echo ; echo ; bold
echo "Repositories"
white ; bold
cat << EOREPO1

The system has to know where to look to find repositories. In Debian-based distributions
of GNU/Linux, this is done through a configuration file:

EOREPO1
green ; bold
echo "/etc/apt/sources.list"
white ; echo
echo "This file on Ubuntu 7.04, and on INX since it is Ubuntu 7.04 without the bells and whistles,"
echo "has lines in it something like this:"
echo ; unbold
echo "deb http://archive.ubuntu.com/ubuntu/ feisty main"
echo "deb http://archive.ubuntu.com/ubuntu/ feisty universe"
echo
echo ; bold
echo "It can also have lines ending \"feisty-security main\" or \"feisty-security universe\""
echo "and so on, with another category being \"feisty-updates\", and another repository"
echo "being \"multiverse\""
echo
echo "\"Feisty\" is just the nickname for the 7.04 version of Ubuntu. 7.04 means \"2007, April\""
echo
echo "The three repositories for Ubuntu are main, universe and multiverse. Security and updates"
echo "are pretty self-explanatory. In Debian the terminology is different, but the idea is the"
echo "same. In fact that's backwards, since all this comes from Debian, of course. In Ubuntu we"
echo "also have a \"restricted\" repository, which contains things that are not "
echo "\"Free as in Freedom\", like proprietary kernel modules (drivers) for graphics cards, and"
echo "other hardware."
echo
echo "The important thing to grasp is that we are pointing to a location on the Internet for"
echo "these repositories, and that /etc/apt/sources.list is where the tools \"look\" to see"
echo "where to find software. (There are actually duplicate repositories in many countries.)" 
echo
echo "Once this file is correctly set up, we tell the system to retrieve the data it needs in"
echo "order to find the software packages and download them..."

f-tutescape
printf "\n\n\n\n"
echo "The command to update this data is:"
echo ; yellow
echo "sudo apt-get update"
echo ; white
echo "if we are using the apt tool. (We will talk about \"aptitude\" later)."
echo "You can have a look for yourself what this looks like - type the command above."
echo "If you are not connected, or on a slow connection like dial-up, just ctrl+d or exit."
echo ; unbold
/bin/bash
echo ; bold
echo "When the update command is run, you see the data files downloading - not the programs."
echo "We are just informing our high-tech machine how to find things for us..."
echo
echo "Now we can install things. Usually the first thing we do is to run a complete system"
echo "upgrade with:"
echo ; yellow
echo "sudo apt-get upgrade"
white ; echo
echo "On a live CD like INX this is a bit pointless, since it will evaporate on reboot."
echo "Instead, as an example, if you have not done this before, or don't know about this"
echo "command line browser, try this:"
echo ; yellow
echo "sudo apt-get install lynx"
white ; echo
echo "Lynx is a lightning quick text browser - it predates links and elinks. Well worth a"
echo "look. Many prefer it. It is a small download. Look at the information apt gives you"
echo "as it downloads and installs."
echo ; unbold
/bin/bash
echo ; bold
echo "You might want to play around a bit with lynx. It is excellent for quick searches"
echo "when you just need to read some text on a subject, without distractions. You might"
echo "also be surprised to see how many \"cookies\" some sites want to give you ;-)"
echo

f-tutescape
echo ; cyan ; echo
echo "Other apt tools"
echo ; white
echo "It's hard to do justice to the sophistication and brilliance of apt. Here we are just"
echo "scratching the surface. Some useful tools to know about follow, as an introduction."
echo "I will give a few references at the end of this tutorial. Since apt is a Debian invention,"
echo "the most comprehensive information is of course from Debian itself, but the principles"
echo "are the same."
echo ; cyan
echo "Searching for Programs."
echo ; white
cat <<EOAPTCACHE1
There are thousands of packages available. This can be overwhelming, especially since many
of the packages have cryptic names like "lib-what-on-earth1.65"... well, for most people
the name might as well be that!

We can narrow things down, though. The sequence is usually like this:

EOAPTCACHE1
yellow
echo "apt-cache search something we need"
echo
echo "apt-cache show one-that-looks-interesting"
echo ; white
echo "Let's take an example. Making something like INX is a learning and discovery process"
echo "just as much as learning to use the command line or Linux itself. In the process, I"
echo "looked for a music player that would both be easy to use and pleasant to look at."
echo "I already knew and liked the cplay player (which incidentally is included in INX),"
echo "but I wanted something a bit more sophisticated that could deal with streams better,"
echo "... and have some colour :-)"
echo
echo "So, I used apt-cache search  ..."

f-tutescape
printf "\n\n\n\n"
echo "The command I typed was something like:"
echo ; yellow
echo "apt-cache search console music player"
echo ; white
echo "The output was like this. I'm running the command here - I hope you did \"apt-get update\" ... "
echo ; unbold
apt-cache search console music player	
echo ; bold
echo "I thought \"moc\" looked like a possibility, so I followed up with:"
echo ; yellow
echo "apt-cache show moc | less"
echo ; white
echo "The output from which looks like this..."
unbold
f-tutescape
echo ; echo
apt-cache show moc | less
echo ; bold
echo "As you see, there's quite a bit of information here, some or most of which is "
echo "probably incomprehensible - but the gold is in the Description section!"
echo
echo "As you should know by now, moc is included in INX. I even wrote a green and gold theme"
echo "for it, since that was the default colour scheme I ended up choosing for INX."
echo
echo "If you really don't care about the details of an apt-cache show , you can use grep"
echo "something like this:"
echo ; yellow
echo "apt-cache show moc | grep -A 10 Description"
echo ; white
echo "Which gives you the first 10 lines of the Description section."
echo

f-tutescape
clear ; cyan ; printf "\n\n\n\n\n"
echo "I can't find the command to run my shiny new program!"
white ; echo
echo "This is less obvious - and introduces the underlying packaging system \"dpkg\""
echo "to the discussion. The easiest way to find the command name, when the obvious fails,"
echo "is to do this:"
echo ; yellow
echo "dpkg -L <packagename> | grep bin"
echo ; white
echo "For example, the command for moc is not \"moc\"..."
echo "Hit space to see the output of"
echo ; yellow
echo "dpkg -L moc | grep bin"
white ; unbold ; echo
read -s -n 1
dpkg -L moc | grep bin
echo ; bold
echo "dpkg -L lists all the files in a package - grep winnows out irrelevant lines."
echo 
echo "Traps for young players: if the program is a game, it is probably in /usr/games -"
echo "so we try \"dpkg -L <packagename> | grep games\" instead."
echo
echo "More about dpkg later..."

f-tutescape
echo ; cyan ; printf "\n\n\n\n"
echo "More apt stuff..."
echo ; white
echo "Sometimes we want to find out which package comtains a particular file. There is"
echo "an apt tool for that as well - but it is not installed by default. In a nice twist,"
echo "we can install it using apt!"
echo ; yellow
echo "sudo apt-get install apt-file && sudo apt-file update"
white ; echo
echo "The \"&&\" makes sure that the first command completes without error before"
echo "proceeding to the second command, by the way. This construct can be quite useful."
echo
echo "In this case we are installing the tool, then updating apt-file's data base so it can find"
echo "what we are looking for. To do a simple search for the package containing a file"
echo "we can then do:"
echo ; yellow
echo "apt-file search <filename>"
echo ; white
echo "apt-file tends to take a while to search - after all, it is dealing with up to"
echo "twenty thousand packages containing a huge number of files."
echo 
echo "Its advantage is that you don't need to have a package installed on your machine for this tool"
echo "to find its contents."

f-tutescape
printf "\n\n\n\n"
echo "For installed files, a far quicker tool is \"dlocate\""
echo
echo "Yes, you guessed - the command to install it is:"
echo ; yellow
echo "sudo apt-get install dlocate"
white ; echo ; echo
printf "Of course, sometimes we want to" ; yellow ; printf " remove" ; white ; printf " packages."
echo "To do that, we can use:"
echo ; yellow
echo "sudo apt-get remove <packagename>"
white ; echo
echo "This removes the package, but not its configuration files - to completely obliterate"
echo "a package, we need:"
echo ; yellow
echo "sudo apt-get --purge remove <packagename>"
printf "\n\n"
white
echo "apt now includes a tool for removal of packages that are no longer used by the system."
echo ; yellow
echo "sudo apt-get autoremove"

f-tutescape

cyan ; echo ; echo
echo "Dependencies"
white ; echo
echo "To install programs that depend on a number of packages, apt has to know about"
echo "dependencies. There are tools to show us these, as well. For instance, here is"
echo "the result of"
echo ; yellow
echo "apt-cache depends lynx"
white ; echo ; unbold
apt-cache depends lynx
echo ; bold
echo "lynx is a relatively simple package, of course. Some packages are themselves"
echo "tiny, containing only listings of dependencies, but depending on many others."
printf "Such packages are known as "
yellow ; printf " metapackages " ; white ; echo ; echo
echo "For instance, here is the result of"
echo ; yellow
echo "apt-cache depends xorg | less"

f-tutescape
white ; unbold
apt-cache depends xorg | less
echo ; bold
echo "And here is the result of:"
echo ; yellow
echo "apt-cache show xorg | grep -A 9 Description"
white ; unbold ; echo
apt-cache show xorg | grep -A 9 Description
echo ; bold
echo "Which shows that \"xorg\" is a metapackage - a way to tell apt which things to install."

f-tutescape
echo ; echo ; cyan
echo "Aptitude"
white 
cat << EOAPTITUDE1

Aptitude is, if you like, a more clever version of apt. That isn't quite right, but it will
do for now :-)

Unlike apt, which is a pure command-line front end to dpkg, aptitude can also be used as a
full screen console application. Some people prefer to use it that way - you can explore the
interface a bit...

I will run it without administrative privileges here - which means that you can't use it to
install or remove anything. Of course, normally you would run it with sudo, for root powers!

EOAPTITUDE1
f-tutescape
aptitude
clear
echo
echo ; bold ; white
echo "So that interface is one obvious difference..."
echo "Many people, though, use aptitude in the same way as apt - from the command line."
echo
echo "The commands are very similar, but in many cases simpler. For instance, to purge a"
echo "package we can simply type:"
echo ; yellow
echo "sudo aptitude purge <packagename>"
white ; echo
echo "Most of the commands are interchangeable with apt's options. For example:"
echo ; yellow
echo "sudo aptitude install foo"
echo
echo "sudo aptitude remove foo"
echo
echo "sudo aptitude update"
echo
echo "sudo aptitude upgrade"
white ; echo
echo "The output format of commands like"
echo ; yellow
echo "aptitude search <keywords>"
echo
echo "aptitude show <packagename>"
echo ; white
echo "is better and more readable, too."
echo
echo "So is aptitude just plain better than apt?"


f-tutescape

printf "\n\n\n\n" ; cyan
echo "Well, it depends." 
echo ; white
echo "Umm... that wasn't meant to be a pun, but I guess it is appropriate..."
echo
echo "Aptitude handles dependencies in a \"smarter\" manner - for some value of \"smarter.\""
echo "Apt just grabs what is needed - aptitude also grabs what is \"recommended\"."
echo
echo "In addition, when removing packages, aptitude will also remove any packages that it"
echo "automatically installed as dependencies. This can be very convenient, or absolutely"
echo "annoying, depending on what you are wanting to achieve."
echo
echo "An example would be a metapackage installed with aptitude. Apt will just remove the"
echo "metapackage (tiny), but aptitude will remove all its dependencies as well."
echo
echo "Briefly then: aptitude is great, as long as you want this behaviour. It is also more"
echo "easily learnt, because all the commands use \"aptitude\" - whereas with apt you need"
echo "to remember to use apt-cache where relevant, and know which options apply to each tool."
echo
echo "Of course, aptitude is smart enough so that you can unset unwanted options. I will run"
echo ; yellow
echo "aptitude help | less"
echo ; white
echo "so you can look. (Actually the \"help\" option doesn't exist as such - it should be -h"
echo "The result is the same - you get the help text) ;-) "

f-tutescape
unbold
aptitude help | less

printf "\n\n\n"
bold
echo "Another front end to the packaging system is \"dselect\". Some people swear by it -"
echo "others swear at it :-)"
printf "\n\n\n"
echo "Here is the help for apt-get - notice that apt-get has a few tricks that aptitude lacks."
echo "Most of the time, aptitude is a better choice, but apt has its uses too."
f-tutescape
unbold
apt-get -h | less
bold ; echo
echo "You probably remember this from the inx intro:"
echo ; unbold
apt-get moo
echo ; bold
echo "That's"
echo ; yellow
echo "apt-get moo"
echo ; white
echo "apt-get has Super Cow Powers ..."
echo
f-tutescape
printf "\n\n\n\n\n\n\t"
echo "Aptitude lacks Super Cow Powers... and claims not to contain any \"Easter Eggs\""
echo
sleep 2
echo ; yellow
echo "But..."
sleep 3
green
echo "       ...no     .... *cough*  ...that would be telling... ;-)"

f-tutescape
printf "\n\n\n\n\n\t"
echo "OK - hint: the -v option means \"verbose\". -v -vv ...  Heard any verbose moos lately?"
f-tutescape
printf "\n\n\n"
cyan
echo "I promised more about dpkg..."
white ; echo
echo "dpkg is the tool that lurks under the surface of apt and aptitude - but it also has"
echo "important functions in the configuration of Debian-based systems. A lot of them."
echo
echo "Rather too many options for this tutorial - so again, we are skimming the surface."
echo ; echo
echo "Some of the more common and useful options for dpkg are:"
echo ; yellow ; echo
printf "sudo dpkg -i <package>		" ; white ; printf "installs <package>"
echo ; yellow
printf "sudo dpkg -r <package>          " ; white ; printf "removes  <package>"
echo ; echo
echo "dpkg is the actual installation and configuration tool - it does no dependency checks."
echo "That is aptitude's or apt's job."
echo
echo "dpkg has many other uses though. For example, if we have issues with a program, we"
echo "can often fix the configuration with:"
echo ; yellow
echo "sudo dpkg-reconfigure <packagename>"
white ; echo
echo "The underlying package system is also tied to tools like the \"alternatives\" system."
echo "the command:"
echo ; yellow
echo "sudo update-alternatives --all"
echo ; white
echo "Will show you *all* the alternatives..."
echo
echo "Hint: Only change them if you know why you are doing so."

f-tutescape
echo ; cyan
echo "Other useful dpkg commands"
echo ; white
echo "We have already seen the uses of"
echo ; yellow
echo "dpkg -L <packagename>"
echo ; white
echo "The lower-case version does something quite different - it lists packages."
echo ; yellow
echo "dpkg -l <packagename1> <packagename2> ..."
echo ; white
echo "You can use wildcards with dpkg -l if you wish - for example:"
echo ; yellow
echo "dpkg -l *linux*"
echo ; white
echo "The dpkg help is rather cryptic in places - but have a look anyway. \"man dpkg\""
echo "is even more so - but a very useful reference."
echo
echo "Here is the short help for dpkg:"

f-tutescape
unbold
dpkg --help | less
echo ; bold

f-tutescape

ref ()
{
clear
printf "\n\n\n\n"
echo ; yellow
echo "References"
echo ; green
echo "If you got this far, congratulations... further reading on apt. aptitude and dpkg:"
white 
echo
echo "1: Take me to the Debian Apt-Howto with the elinks text browser."
echo "2: Take me to the Debian Apt-Howto with the links2 -g graphical browser."
echo "3: Take me to the Ubuntu AptHowto Wiki Page in the graphical browser."
echo "4: Take me to the Ubuntu AptitudeSurvivalGuide in the graphical browser"
echo "5: Open all three pages in tabs, in elinks."
green
echo
echo "Any non-number key to return to the tutorial menu."
white
read -s -n 1 APT
case $APT in
	1)
	f-sup
	elinks http://www.debian.org/doc/manuals/apt-howto/
	ref
	;;
	2)
	links2 -g http://www.debian.org/doc/manuals/apt-howto/
	ref
	;;
	3)
	links2 -g https://help.ubuntu.com/community/AptGetHowto
	ref
	;;
	4)
	links2 -g https://help.ubuntu.com/community/AptitudeSurvivalGuide
	ref
	;;
	5)
	elinks http://www.debian.org/doc/manuals/apt-howto/ https://help.ubuntu.com/community/AptGetHowto https://help.ubuntu.com/community/AptitudeSurvivalGuide
	ref
	;;
	
	*)
	f-tutorial
	;;
esac

}	
ref
f-tutorial
}