diff --git a/include/TextStream.hpp b/include/TextStream.hpp
index bfacd06..ed1c554 100644
--- a/include/TextStream.hpp
+++ b/include/TextStream.hpp
@@ -85,6 +85,13 @@ public:
      */
     std::string readLineAt(Uint32 line);
 
+    /*! \brief Writes a line at the given address.
+     *
+     *  \param line The address to write to.
+     *  \param str The string to write.
+     */
+    void writeLineAt(Uint32 line, const std::string& str);
+
     /*! \brief Sets the current line in the Stream.
      *
      *  \param line The line to seek to.
diff --git a/src/TextStream.cpp b/src/TextStream.cpp
index c14d2b7..ac25de2 100644
--- a/src/TextStream.cpp
+++ b/src/TextStream.cpp
@@ -52,6 +52,8 @@ TextStream::TextStream(const std::string& filename, TextMode fileMode, AccessMod
 
 void  TextStream::save(const std::string& filename)
 {
+    if (m_accessmode != WriteOnly || m_accessmode != ReadWrite)
+        throw InvalidOperationException("Stream not open for writing");
     if (filename != std::string())
         m_filename = filename;
 
@@ -95,7 +97,7 @@ std::string TextStream::readLine()
 void  TextStream::writeLine(const std::string& str)
 {
     if (m_accessmode != WriteOnly || m_accessmode != ReadWrite)
-        throw InvalidOperationException("Stream not open for reading");
+        throw InvalidOperationException("Stream not open for writing");
     else if (m_currentLine > m_lines.size())
     {
         m_lines.push_back(str);
@@ -109,7 +111,7 @@ void  TextStream::writeLine(const std::string& str)
 void TextStream::writeLines(std::vector<std::string> strings)
 {
     if (m_accessmode != WriteOnly || m_accessmode != ReadWrite)
-        throw InvalidOperationException("Stream not open for reading");
+        throw InvalidOperationException("Stream not open for writing");
 
     for (std::string s: strings)
         writeLine(s);
@@ -144,6 +146,17 @@ std::string TextStream::readLineAt(Uint32 line)
     return m_lines[line - 1];
 }
 
+void TextStream::writeLineAt(Uint32 line, const std::string& line)
+{
+    if (m_accessmode != WriteOnly || m_accessmode != ReadWrite)
+        throw InvalidOperationException("Stream not open for reading");
+    if (line <= 0)
+        throw InvalidOperationException("A line cannot be zero indexed");
+
+    m_currentLine = line;
+    writeLine(line);
+}
+
 std::vector<std::string> TextStream::readAllLines()
 {
     if (m_accessmode != ReadOnly || m_accessmode != ReadWrite)