Windows Instructions:
After downloading, double-click install.exe.
You may need to install a Java 1.5.0 (or later) virtual machine before installation of BGBlitz. You can download one free of charge from Sun's Java web site. I recommend the current JRE 1.5.0 or Sun Java 6. You may also download a BGBlitz version that has a special adopted Java 6 version included. You will also achieve the best performance with this specially tuned download.

Mac OS X Instructions:
The installer is a compressed disk image. It will be decompressed either automatically after downloading or you have to double click on it. Double click again on the resulting BGBlitz.dmg to mount the image. Then copy the directory BGBlitz to any convenient place.
Requires Mac OS X 10.3 or later.

Mac OS Classic (8.1 or greater) Instructions:
After downloading, double-click install.
Requires PowerPC and Mac OS 8.1 or later
You may need to install Mac OS Runtime for Java (MRJ) 2.2 or newer before installation of BGBlitz.
The installer is MacBinary encoded and will be automatically decoded after downloading. If it does not, you can decode it using StuffIt Expander 4.5 or later.

Linux / FreeBSD Instructions:
After the download open a shell and cd to the directory where you downloaded the installer. At the prompt type:

gzip -d bgblitz.tar.gz
tar xf bgblitz.tar

if you have GNU tar

tar xzf bgblitz.tar.gz

replaces the above two commands. Now that BGBlitz is unpacked, move the directory BGBlitz to any convenient place. Then, still with the shell, go to the BGBlitz directory, e.g.

cd BGBlitz

now you have to edit the bgblitz.sh (if Java is reachable on the path and you always start BGBlitz from the installation folder, you can leave bgblitz.sh as it is). In the second line "JAVA=java" replace "java" with the full path to Java e.g. /usr/bin/java, if java is not on the PATH already or if you want to use another version of Java.
In the third line "BGBLITZ_HOME=." please enter the full path to the installation directory e.g. BGBLITZ_HOME=$HOME/BGBlitz.
Now typing ./bgblitz.sh in the shell or a double click in a file manager should be sufficient to start BGBlitz.
You may need to install a Java 1.4.2 (or later) virtual machine before installation of BGBlitz. You can download one from Sun's Java web site or contact your OS manufacturer.

For Linux I recommend either JRE 1.4.2 or a newer version. For FreeBSD please use Java 1.5 of the FreeBSD Foundation.Other virtual machines may not work, or look wrong.

These instructions should work for most UNIX variants; you just need a reasonable Java implementation. For OS/2 do the same with the bgblitz.cmd.
You may ask, why is this so complicated, aren't there any better installers? I used a commercial installer and that led to a lot of problems (didn't find a lib here or an error there.) It was in my honest opinion ridiculous, that the installer made a portable program unusable, so I decided to use this primitive but working way and being independent from any installer and peculiar libraries, just using pretty simple shell stuff.