The installation package for Slackware is .tgz
Is it possible to compile .tar.gz or .tar.bz2
and install?

Sure, why not?
A Slackware package contains precompiled software. However, do not assume that all *.tgz files are Slackware packages.
Source code can be archived and compressed into all sorts of file formats: *.tar.gz *.tar.xz *.tar.bz2 *.tgz etc... and you can make a Slackware package out of these sources by compiling them and conveniently packaging the resulting binaries.

Eric

I have tar.gz file
I want to install it in my Slackware 12.2.

Is it nescessary to compile it and make .tgz package?
Or
After extracting I can do:
make
make install
./program

You could use src2pkg.
http://www.src2pkg.net/

sure, you can
normally is
default prefix is /usr/local , but you can change it with

Not all programs use configure/make, same use cmake or qmake

General advice: software installation is dependent on the software you're trying to install (amongst other things). While many pieces of software are installed in the same way (e.g. configure, make, make install as outlined above), you should always check the documentation for whatever you want to install, to find any specific installation notes.

Most part of "linux" software is compiled for slackware in *.tgz, take a look here:

http://www.slacky.eu/aadm/pkgs/index.php?ver=6

Put the name of your package and after push on enter, if the package you're looking for doesn't exist on slacky.eu find it on slackbuilds.org

There is a lot of software there Install software using slackbuilds and/or using *.tgz; *.txz, the normal compilation-->installation (./configure; make;make install) is a right procedure but too general, some software requires more infos to install to the right path and make a right installation(I mean, a clean installation) Learn how to make a slackbuild as first as possible, it's useful for your slackware and remember to install dependencies too

I would recommend going to http://www.slackbuilds.org and looking for a build script. Also read the howto.

If you don't see a package there then you can make your own slackbuild from the template on sb.org. Or you could use the DESTDIR variable to install into a directory and run makepkg on it.

It is generally frowned upon to download precompiled packages from 3rd party websites, where who knows what options or dependencies they may have been compiled with.

Here are the slacky.eu's packages:

http://repository.slacky.eu/slackwar.../ChangeLog.txt

They're really a lot...

We get your point... there is no need to keep repeating it.

Eric

Eheh sorry guys Sorry Bob...