TV reads several settings from the environment, whic is platform-specific:
Amiga
Unix
Windows


Amiga
The following list shows which Assigns of AmigaDOS are of interest
to TV:

TVback:      Assigned to the directory in which backup-files will be
             created. Backup-files contain all the user-commands entered
             during a TV-session.
             The -b option will override the TVback:-file, if specified.

TVfont:      Assigned to a bitmap-file for a (non-proportional) font in
             the FONTS:-directory. If TVfont: is left unassigned, the
             Topaz font in size 8 will be used by default.

TVhelp:      Assigned to the directory containing the AmigaGuide files
             TV.guide#?. This is only used in the example TVini:-file, for
             the definition of function key 0 (i.e. the HELP-key).
             Please be aware that the AmigaGuide is obsolete, and will no
             longer be maintained. The HTML documentation is the proper
             source now.

TVini:       Assigned to an initialization-file containing valid TV-
             commands. This file is executed at the start of any TV session.
             The -i option will override the TVini:-file, if specified.
             During execution of TVini:, TV will not (yet) be in
             interactive mode.


Unix
The following list shows which environment variables of Unix are of
interest to TV:

$TVback      Set to the directory in which backup-files will be
             created. Backup-files contain all the user-commands entered
             during a TV-session.
             The -b option will override the $TVback-file, if specified.

$TVini       Set to an initialization-file containing valid TV-
             commands. This file is executed at the start of any TV session.
             The -i option will override the $TVini-file, if specified.
             During execution of $TVini, TV will not (yet) be in
             interactive mode.

$TVlines     Set to an integer value defining the vertical size of the
             window to be opened.

$TVcolumns   Set to an integer value defining the horizontal size of the
             window to be opened.


Windows
The following list shows which environment variables of Windows are of
interest to TV:

%TVBACK%     Set to the directory in which backup-files will be
             created. Backup-files contain all the user-commands entered
             during a TV-session.
             The -b option will override the %TVBACK%-file, if specified.

%TVINI%      Set to an initialization-file containing valid TV-
             commands. This file is executed at the start of any TV session.
             The -i option will override the %TVINI%-file, if specified.
             During execution of %TVINI%, TV will not (yet) be in
             interactive mode.

Note that these Windows environment variables can be created with the same
names as under Unix and AmigDOS (TVback instead of TVBACK, TVini instead of
TVINI) and TV will find them and work correctly. For those using MingW/MSYS,
it is better to use the upper-case versions only, as that platform will only
retrieve them that way.