diff --git a/cwFileSys.cpp b/cwFileSys.cpp
index b4b035f..034c2af 100644
--- a/cwFileSys.cpp
+++ b/cwFileSys.cpp
@@ -241,6 +241,68 @@ char* cw::filesys::makeVersionedFn( const char* dir, const char* fn_prefix, cons
   return fnOut;  
 }
 
+char* cw::filesys::replaceDirectory( const char* fn0, const char* dir  )
+{
+  pathPart_t* pp = nullptr;
+  char*       fn = nullptr;
+  
+  if((pp = pathParts( fn0 )) == nullptr )
+  {
+    cwLogError(kOpFailRC,"File name parse failed.");
+    return nullptr;
+  }
+
+  if((fn = makeFn( dir, pp->fnStr, pp->extStr)) == nullptr )
+  {
+    cwLogError(kOpFailRC,"Unable to replace directory.");
+  }
+
+  mem::release(pp);
+  return fn;
+  
+}
+
+char* cw::filesys::replaceFilename(  const char* fn0, const char* name )
+{
+  pathPart_t* pp = nullptr;
+  char*       fn = nullptr;
+  
+  if((pp = pathParts( fn0 )) == nullptr )
+  {
+    cwLogError(kOpFailRC,"File name parse failed.");
+    return nullptr;
+  }
+
+  if((fn = makeFn( pp->dirStr, name, pp->extStr)) == nullptr )
+  {
+    cwLogError(kOpFailRC,"Unable to replace file name.");
+  }
+
+  mem::release(pp);
+  return fn;
+}
+
+char* cw::filesys::replaceExtension( const char* fn0, const char* ext  )
+{
+  pathPart_t* pp = nullptr;
+  char*       fn = nullptr;
+  
+  if((pp = pathParts( fn0 )) == nullptr )
+  {
+    cwLogError(kOpFailRC,"File name parse failed.");
+    return nullptr;
+  }
+
+  if((fn = makeFn( pp->dirStr, pp->fnStr, ext)) == nullptr )
+  {
+    cwLogError(kOpFailRC,"Unable to replace file extension.");
+  }
+
+  mem::release(pp);
+  return fn;
+}
+
+
 
 char* cw::filesys::expandPath( const char* dir )
 {
diff --git a/cwFileSys.h b/cwFileSys.h
index af9a6ff..30be347 100644
--- a/cwFileSys.h
+++ b/cwFileSys.h
@@ -27,6 +27,12 @@ namespace cw
     char* vMakeVersionedFn(const char* dir, const char* fn_prefix, const char* ext, va_list vl );
     char* makeVersionedFn( const char* dir, const char* fn_prefix, const char* ext, ... );
 
+    // Replace the directory/name/extension part of a complete path.
+    // The returned string must be release by a call to mem::release() or mem::free().
+    char* replaceDirectory( const char* fn, const char* dir  );
+    char* replaceFilename(  const char* fn, const char* name );
+    char* replaceExtension( const char* fn, const char* ext  );
+
 
     // The returned string must be released by a call to mem::release() or mem::free().
     char* expandPath( const char* dir );
@@ -44,7 +50,7 @@ namespace cw
 
     // Given a file name decompose it into a directory string, file name string and file extension string.
     // The returned record and the strings it points to are contained in a single block of
-    // memory which must be released by a call to memRelease() or memFree()
+    // memory which must be released by a call to mem::release() or mem::free()
     pathPart_t* pathParts( const char* pathNameStr );
 
     // Flags used by dirEntries 'includeFlags' parameter.