use strict;
use warnings;

use Data::Dumper;
use IO::File;

print qq{Files to read\n};
my @dataFiles = glob q{spw592341.data*};
print qq{     $_\n} for @dataFiles;
print qq{\n};

my $rhFiles = {};

foreach my $file (@dataFiles)
{
    openFile($file);
    getLine($file);
}

showData(q{After reading first line});

foreach my $file (@dataFiles)
{
    getLine($file);
}

showData(q{All files read again});

getLine($dataFiles[2]);

showData(q{Read third file in list});

getLine(q{spw592341.dataD});

showData(q{Read spw592341.dataD});

foreach my $file (@dataFiles)
{
    closeFile($file);
}

showData(q{After closing all files});

sub closeFile
{
    my $file = shift;
    $rhFiles->{$file}->{handle}->close()
       or die qq{close: $file: $!\n};
    delete $rhFiles->{$file}->{handle};
}

sub getLine
{
    my $file = shift;
    $rhFiles->{$file}->{buffer}
       = $rhFiles->{$file}->{handle}->getline();
    chomp $rhFiles->{$file}->{buffer};
}

sub openFile
{
    my $file = shift;
    my $fh = IO::File->new($file, O_RDONLY)
       or die qq{open: $file: $!\n};
    $rhFiles->{$file}->{handle} = $fh;
}

sub showData
{
    my $msg = shift;
    print qq{\n$msg\n};
    my $dd = Data::Dumper->new(
       [$rhFiles], [qw{rhFiles}])->Indent(1);
    print $dd->Dumpxs();
}