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open my $fh, '>', $file_name or die "Cannot open $file_name: $!";

my %handles = get_write_handles(qw/col1.txt col2.txt col3.txt/);

...
  }
  return %file_handles;
}

print { $handles{'in.txt'} } "something\n";

foreach (values %handles) {
  print $_ "something\n";
}

sub get_read_handles {
  my @file_names = @_;
...
  }
  return @file_handles;
}

sub get_append_handles {
  my @file_names = @_;
...
  }
  return @file_handles;
}