Files to read
     spw592341.dataA
     spw592341.dataB
     spw592341.dataC
     spw592341.dataD


After reading first line
$rhFiles = {
  'spw592341.dataB' => {
    'handle' => bless( \*Symbol::GEN1, 'IO::File' ),
    'buffer' => 'spw592341:dataB:line1'
  },
  'spw592341.dataD' => {
    'handle' => bless( \*Symbol::GEN3, 'IO::File' ),
    'buffer' => 'spw592341:dataD:line1'
  },
  'spw592341.dataA' => {
    'handle' => bless( \*Symbol::GEN0, 'IO::File' ),
    'buffer' => 'spw592341:dataA:line1'
  },
  'spw592341.dataC' => {
    'handle' => bless( \*Symbol::GEN2, 'IO::File' ),
    'buffer' => 'spw592341:dataC:line1'
  }
};

All files read again
$rhFiles = {
  'spw592341.dataB' => {
    'handle' => bless( \*Symbol::GEN1, 'IO::File' ),
    'buffer' => 'spw592341:dataB:line2'
  },
  'spw592341.dataD' => {
    'handle' => bless( \*Symbol::GEN3, 'IO::File' ),
    'buffer' => 'spw592341:dataD:line2'
  },
  'spw592341.dataA' => {
    'handle' => bless( \*Symbol::GEN0, 'IO::File' ),
    'buffer' => 'spw592341:dataA:line2'
  },
  'spw592341.dataC' => {
    'handle' => bless( \*Symbol::GEN2, 'IO::File' ),
    'buffer' => 'spw592341:dataC:line2'
  }
};

Read third file in list
$rhFiles = {
  'spw592341.dataB' => {
    'handle' => bless( \*Symbol::GEN1, 'IO::File' ),
    'buffer' => 'spw592341:dataB:line2'
  },
  'spw592341.dataD' => {
    'handle' => bless( \*Symbol::GEN3, 'IO::File' ),
    'buffer' => 'spw592341:dataD:line2'
  },
  'spw592341.dataA' => {
    'handle' => bless( \*Symbol::GEN0, 'IO::File' ),
    'buffer' => 'spw592341:dataA:line2'
  },
  'spw592341.dataC' => {
    'handle' => bless( \*Symbol::GEN2, 'IO::File' ),
    'buffer' => 'spw592341:dataC:line3'
  }
};

Read spw592341.dataD
$rhFiles = {
  'spw592341.dataB' => {
    'handle' => bless( \*Symbol::GEN1, 'IO::File' ),
    'buffer' => 'spw592341:dataB:line2'
  },
  'spw592341.dataD' => {
    'handle' => bless( \*Symbol::GEN3, 'IO::File' ),
    'buffer' => 'spw592341:dataD:line3'
  },
  'spw592341.dataA' => {
    'handle' => bless( \*Symbol::GEN0, 'IO::File' ),
    'buffer' => 'spw592341:dataA:line2'
  },
  'spw592341.dataC' => {
    'handle' => bless( \*Symbol::GEN2, 'IO::File' ),
    'buffer' => 'spw592341:dataC:line3'
  }
};

After closing all files
$rhFiles = {
  'spw592341.dataB' => {
    'buffer' => 'spw592341:dataB:line2'
  },
  'spw592341.dataD' => {
    'buffer' => 'spw592341:dataD:line3'
  },
  'spw592341.dataA' => {
    'buffer' => 'spw592341:dataA:line2'
  },
  'spw592341.dataC' => {
    'buffer' => 'spw592341:dataC:line3'
  }
};