How to unpack tarfiles:

First you must set the scripting environment variable to some root of a directory tree that will contain the software from the book. On Unix (running a shell with Bash syntax) you can write (preferably in a start-up file like .bashrc)
```
export scripting=$HOME/scripting
```
On Windows you can write something like
```
set scripting=C:\Documents and Settings\hpl\My Documents\scripting
```
in the C:\AUTOEXEC.BAT file. On Windows XP and 2000, C:\autoexec.bat may fail to execute. If the environment variables are not properly set, you can set them interactively by launching the Edit dialog from My Computer - Properties - Advanced - Environment Variables.
Unpacking tarfiles:
Place the file you want to unpack, say its name is scripting-src.tar.gz, in the $scripting directory and go to this directory. On a Linux machine you can unpack the file with the command
```
tar xvzf scripting-src.tar.gz
```
On other Unix machines you may have to perform a two-step procedure:
```
gunzip scripting-src.tar.gz
tar xvzf scripting-src.tar
```
On Windows you can open the file with WinZip and choose the value of %scripting% as destination directory.