Display a file and directory selection pop-up window suitable for retrieving an existing file name. The full path of the file is stored in an environment variable called OPENBOX.
OPENBOX "title" spec1;spec2;spec3;...
title A string which specifies the window caption. spec1;spec2;spec3;... Specifies the file names which will be listed.
Parameters spec1;spec2;spec3;... can contain wildcard characters.
Also see command SAVEBOX.