diff --git a/src/include/file_io.h b/src/include/file_io.h
index e5c990083c4022c87e085c89cad2e8db213e9c42..312517f19b9f7db9d7420b7c4cd1247b04d94619 100644
--- a/src/include/file_io.h
+++ b/src/include/file_io.h
@@ -5,6 +5,8 @@
 #ifndef INCLUDE_FILE_IO_H_
 #define INCLUDE_FILE_IO_H_
 
+#include <vector>
+
 /*! \class FileSchema
  *
  * \brief File content descriptor.
@@ -156,4 +158,48 @@ class HDFFile {
 	       hid_t dapl_id=H5P_DEFAULT, hid_t dxpl_id=H5P_DEFAULT
   );
 };
+
+/*! \class VirtualAsciiFile
+ *
+ * \brief Virtual representation of an ASCII file.
+ */
+class VirtualAsciiFile {
+protected:
+  //! \brief A vector of strings representing the file lines.
+  std::vector<std::string> *file_lines;
+  //! \brief The name of the file.
+  std::string _file_name;
+
+public:
+  const std::string& file_name = _file_name;
+
+  /*! \brief VirtualAsciiFile instance constructor.
+   *
+   * \param name: `const string&` Reference to a string for the file name.
+   */
+  VirtualAsciiFile(const std::string& name);
+
+  /*! \brief VirtualAsciiFile copy constructor.
+   *
+   * \param rhs: `const VirtualAsciiFile&` Reference to a VirtualAsciiFile instance.
+   * \param name: `const string&` Name of the copy (optional, default is the same as original).
+   */
+  VirtualAsciiFile(const VirtualAsciiFile& rhs, const std::string& name = "");
+
+  /*! \brief VirtualAsciiFile instance destroyer.
+   */
+  ~VirtualAsciiFile();
+
+  /*! \brief Append a line at the end of the file.
+   *
+   * \param line: `const string&` Reference to a string representing the line.
+   */
+  void append(const std::string& line);
+
+  /*! \brief Write virtual file contents to a real file on disk.
+   *
+   * \return result: `int` A result code (0 if successful).
+   */
+  int write_to_disk();
+};
 #endif
diff --git a/src/libnptm/file_io.cpp b/src/libnptm/file_io.cpp
index c196d515e3923a5045373e28ce144c5a1e5de4c1..b7a4b404b7a088c8e0139fad8f0975c1726189f2 100644
--- a/src/libnptm/file_io.cpp
+++ b/src/libnptm/file_io.cpp
@@ -3,6 +3,7 @@
  * \brief Implementation of file I/O operations.
  */
 #include <exception>
+#include <fstream>
 #include <regex>
 #include <string>
 #include <hdf5.h>
@@ -21,6 +22,7 @@
 
 using namespace std;
 
+/* >>> FileSchema class implementation <<< */
 FileSchema::FileSchema(int num_rec, const std::string *rec_types, const std::string *rec_names) {
   num_records = num_rec;
   record_types = new string[num_rec];
@@ -48,7 +50,9 @@ string* FileSchema::get_record_types() {
   for (int i = 0; i < num_records; i++) rec_types[i] = record_types[i];
   return rec_types;
 }
+/* >>> End of FileSchema class implementation <<< */
 
+/* >>> HDFFile class implementation <<< */
 HDFFile::HDFFile(const std::string& name, unsigned int flags, hid_t fcpl_id, hid_t fapl_id) {
   file_name = name;
   if (flags == H5F_ACC_EXCL || flags == H5F_ACC_TRUNC)
@@ -222,3 +226,45 @@ herr_t HDFFile::write(
   }
   return status;
 }
+/* >>> End of HDFFile class implementation <<< */
+
+/* >>> VirtualAsciiFile class implementation <<< */
+VirtualAsciiFile::VirtualAsciiFile(const std::string& name) {
+  _file_name = name;
+  _file_lines = new vector<string>();
+}
+
+VirtualAsciiFile::VirtualAsciiFile(const VirtualAsciiFile& rhs, const std::string& name) {
+  if (name.compare("") == 0) {
+    _file_name = rhs._file_name;
+  } else {
+    _file_name = name;
+  }
+  _file_lines = new vector<string>();
+  for (vector<string>::iterator it = rhs._file_lines->begin(); it != rhs._file_lines->end(); ++it) {
+    _file_lines->push_back(*it);
+  }
+}
+
+VirtualAsciiFile::~VirtualAsciiFile() {
+  if (_file_lines != NULL) delete _file_lines;
+}
+
+void VirtualAsciiFile::append(const string& line) {
+  _file_lines.push_back(line);
+}
+
+int VirtualAsciiFile::write_to_disk() {
+  int result = 0;
+  fstream output_file;
+  output_file.open(file_name, ios::out);
+  if (output_file.is_open()) {
+    for (vector<string>::iterator it = _file_lines->begin(); it != _file_lines->end(); ++it) {
+      output_file << *it;
+    }
+  } else {
+    result = 1;
+  }
+  return result;
+}
+/* >>> End of VirtualAsciiFile class implementation <<< */