SelectSaver - save and restore selected file handle
use SelectSaver;
{
   my $saver = SelectSaver->new(FILEHANDLE);
   # FILEHANDLE is selected
}
# previous handle is selected
{
   my $saver = SelectSaver->new;
   # new handle may be selected, or not
}
# previous handle is selectedA SelectSaver object contains a reference to the file handle that was selected when it was created. If its new method gets an extra parameter, then that parameter is selected; otherwise, the selected file handle remains unchanged.
When a SelectSaver is destroyed, it re-selects the file handle that was selected when it was created.