The following environment variables are recognized by WarpIN:
SET WARPIN_DISPLAYPAGES={YES|NO}
This determines whether WarpIN displays the installation pages at all. If YES is specified (which is the default), you get the regular installation sequence (even though you may set certain default values with the other variables below). If NO is specified, WarpIN will jump directly to the installation with no further chance for you to interfere (except pressing the "Cancel" button).

Specify YES first to test your installation variables. If you're sure that everything works well, change it to NO.

SET WARPIN_INSTALLACTION={REPAIR|ADDREMOVE|DEINSTALL}
This suppresses the "Archive already installed" dialog at the beginning. Note that this variable only has an effect if WarpIN finds that parts of an archive have already been installed.
SET WARPIN_SELECTPACKAGEx={YES|NO}
This selects the package with the index x for installation, depending on whether the argument is YES or NO.

The default selection status is determined by the archive's author in the install script. Note that if the author has specified the NODESELECT attribute with a PCK tag, you can't deselect it with this variable either.

SET WARPIN_TARGETPATHx=path
This sets the target path for the package with the index x. The default is specified in the install script for each archive. If you set the path for a package which has the BASE attribute set in its PCK tag, the other paths are automatically updated.
SET WARPIN_UPDATECONFIGSYS={YES|NO}
This has WarpIN update the CONFIG.SYS file. Note that this has only an effect if the packages to be installed contain any such information. The default is YES.
SET WARPIN_INSTALLWPSCLASSES={YES|NO}
This has WarpIN install additional WPS classes. Note that this has only an effect if the packages to be installed contain any such information. The default is YES.
SET WARPIN_CREATEWPSOBJECTS={YES|NO}
This has WarpIN create WPS objects. Note that this has only an effect if the packages to be installed contain any such information. The default is YES.
SET WARPIN_IFSAMEDATE={PROMPT|SKIP|OVERWRITE}
SET WARPIN_IFEXISTINGOLDER={PROMPT|SKIP|OVERWRITE}
SET WARPIN_IFEXISTINGNEWER={PROMPT|SKIP|OVERWRITE}
These three variables specify the behavior if a file exists already, especially whether WarpIN will prompt the user for a response in the "File exists" dialog. Before WarpIN writes a file to disk, it checks whether that file exists already. If so, the last-write dates of the file on disk and the one in the archive are compared. Depending on the result, one of the three variables applies.

For each of them, the options have the following meaning:

The default values are as follows:
SET WARPIN_IFSAMEDATE=OVERWRITE
SET WARPIN_IFEXISTINGOLDER=OVERWRITE
SET WARPIN_IFEXISTINGNEWER=PROMPT