Environment variables used by wpkg

Submitted by Alexis Wilke on Wed, 05/08/2013 - 02:07

The wpkg tool, as well as the libdebpackages library make use of different environment variables. These are defined below:

Variable Get From Operating System Comments
COMSPEC Library and wpkg Windows The COMSPEC variable is used under MS-Windows when a batch script needs to be run. The variable must be set to a valid value or the execution of any external batch script will fail.
HOME Library All The HOME variable is used to replace the ~ character in a path.
Note that the library has no concept of users so the Unix ~<username>/... syntax is not currently supported.
PROCESSOR_ARCHITECTURE Library Windows The library checks this variable under MS-Windows in an attempt to determine the processor in use. The value may easily be tainted.

IMPORTANT NOTE

The PROCESSOR_ARCHITW6432 variable is tested first, then PROCESSOR_ARCHITECTURE is used. The PROCESSOR_IDENTIFIER variable is ignored when PROCESSOR_ARCHITEW6432 or PROCESSOR_ARCHITECTURE are defined.
PROCESSOR_ARCHITEW6432 Library Windows The library checks this variable under MS-Windows in an attempt to determine the processor in use. The value may easily be tainted.

IMPORTANT NOTE

This variable is tested first. The PROCESSOR_ARCHITECTURE and PROCESSOR_IDENTIFIER variables are ignored when PROCESSOR_ARCHITEW6432 is defined.
PROCESSOR_IDENTIFIER Library Windows The library checks this variable under MS-Windows in an attempt to determine the processor in use. The value may easily be tainted.

IMPORTANT NOTE

The PROCESSOR_IDENTIFIER variable is tested last. The PROCESSOR_IDENTIFIER variable is ignored when PROCESSOR_ARCHITEW6432 or PROCESSOR_ARCHITECTURE are defined.
WPKG_OPTIONS wpkg All This WPKG_OPTIONS variable is used to hold command line options so one does not have to always specify those options on the command line. For example, the --root option could be defined that way to avoid having to redifine it each time you use wpkg. The syntax is the same as on the command. For example: 
WPKG_OPTIONS="--root /tmp/dist"

See also the wpkg configuration file.
WPKG_SUBST Library All The library offers a way to substitute a directory path by a drive letter, just like you do with the subst command line option at a DOS prompt. The variable can include as many definition as you need. The syntax is as follow: 
    <drive letter>=<path to root>[|<current directory>]:...

The drive letter followed by an equal (=) and the path to the root directory of that drive. Optionally, add a current directory after a pipe (|) character. Separate multiple definitions by the colon (:) character. Obviously the path filenames cannot include illegal characters.

There is an example of drive C: and D: definitions:

    export subst="C=/home/wpkg/c_drive|development;D=/mnt/windows-box|dev/mingw"
Note that these definitions work under MS-Windows as well. You want to be very careful to not redefine an existing drive (although everything works either way, it may create some unexpected side effects.)

In most environment the set command used by itself will show you the current value of all the environment variables:

set

To set a variable, use the set or setenv command if necessary. You may also have to export the value. Under Linux you write:

export WPKG_OPTIONS=--verbose

The export command forces the variable to be visible in all the commands and scripts started after that point.

To print out the value of a variable, use the dollar ($) [Unix shells] or the percent (%) [MS-Windows DOS] characters:

echo $HOME
eccho %COMSPEC%

Notice that the % surrounds the variable name.