diff --git a/doc/PDF/colvars-refman-lammps.pdf b/doc/PDF/colvars-refman-lammps.pdf
index 2669b4d16f..a9a1b5624b 100644
Binary files a/doc/PDF/colvars-refman-lammps.pdf and b/doc/PDF/colvars-refman-lammps.pdf differ
diff --git a/lib/colvars/colvar.cpp b/lib/colvars/colvar.cpp
index 3ed512692e..86448fd5f0 100644
--- a/lib/colvars/colvar.cpp
+++ b/lib/colvars/colvar.cpp
@@ -196,6 +196,23 @@ colvar::colvar (std::string const &conf)
     b_Jacobian_force = false;
   }
 
+  if (!tasks[task_scripted]) {
+    colvarvalue::Type const value_type = (cvcs[0])->type();
+    if (cvm::debug())
+      cvm::log ("This collective variable is a "+
+                colvarvalue::type_desc[value_type]+", corresponding to "+
+                cvm::to_str (colvarvalue::dof_num[value_type])+
+                " internal degrees of freedom.\n");
+    x.type (value_type);
+    x_reported.type (value_type);
+  }
+
+  // If using scripted biases, any colvar may receive bias forces
+  // and will need its gradient
+  if (cvm::scripted_forces()) {
+    enable(task_gradients);
+  }
+
   // check for linear combinations
 
   b_linear = !tasks[task_scripted];
@@ -279,17 +296,6 @@ colvar::colvar (std::string const &conf)
     }
   }
 
-  if (!tasks[task_scripted]) {
-    colvarvalue::Type const value_type = (cvcs[0])->type();
-    if (cvm::debug())
-      cvm::log ("This collective variable is a "+
-                colvarvalue::type_desc[value_type]+", corresponding to "+
-                cvm::to_str (colvarvalue::dof_num[value_type])+
-                " internal degrees of freedom.\n");
-    x.type (value_type);
-    x_reported.type (value_type);
-  }
-
   get_keyval (conf, "width", width, 1.0);
   if (width <= 0.0) {
     cvm::error("Error: \"width\" must be positive.\n", INPUT_ERROR);
diff --git a/lib/colvars/colvarbias.cpp b/lib/colvars/colvarbias.cpp
index 7c21c551c8..62783d2aee 100644
--- a/lib/colvars/colvarbias.cpp
+++ b/lib/colvars/colvarbias.cpp
@@ -128,19 +128,23 @@ cvm::real colvarbias::energy_difference(std::string const &conf)
 int colvarbias::bin_num()
 {
   cvm::error ("Error: bin_num() not implemented.\n");
-  return -1;
+  return COLVARS_NOT_IMPLEMENTED;
 }
 int colvarbias::current_bin()
 {
   cvm::error ("Error: current_bin() not implemented.\n");
-  return -1;
+  return COLVARS_NOT_IMPLEMENTED;
 }
 int colvarbias::bin_count(int bin_index)
 {
   cvm::error ("Error: bin_count() not implemented.\n");
-  return -1;
+  return COLVARS_NOT_IMPLEMENTED;
+}
+int colvarbias::replica_share()
+{
+  cvm::error ("Error: replica_share() not implemented.\n");
+  return COLVARS_NOT_IMPLEMENTED;
 }
-
 
 std::ostream & colvarbias::write_traj_label (std::ostream &os)
 {
diff --git a/lib/colvars/colvarbias.h b/lib/colvars/colvarbias.h
index ad24f40f30..887373be91 100644
--- a/lib/colvars/colvarbias.h
+++ b/lib/colvars/colvarbias.h
@@ -34,9 +34,9 @@ public:
   /// Calculate the bin index for a given bias.
   virtual int current_bin();
   //// Give the count at a given bin index.
-  virtual int bin_count(int bin_index);  
+  virtual int bin_count(int bin_index);
   //// Share information between replicas, whatever it may be.
-  virtual void replica_share() {};
+  virtual int replica_share();
 
   /// Perform analysis tasks
   virtual inline void analyse() {}
diff --git a/lib/colvars/colvarbias_abf.cpp b/lib/colvars/colvarbias_abf.cpp
index 812490013c..e992ef693d 100644
--- a/lib/colvars/colvarbias_abf.cpp
+++ b/lib/colvars/colvarbias_abf.cpp
@@ -282,17 +282,17 @@ cvm::real colvarbias_abf::update()
   return 0.0;
 }
 
-void colvarbias_abf::replica_share () {
+int colvarbias_abf::replica_share () {
   int p;
 
   if( !cvm::replica_enabled() ) {
     cvm::error ("Error: shared ABF: No replicas.\n");
-    return;
+    return COLVARS_ERROR;
   }
   // We must have stored the last_gradients and last_samples.
   if (shared_last_step < 0 ) {
     cvm::error ("Error: shared ABF: Tried to apply shared ABF before any sampling had occurred.\n");
-    return;
+    return COLVARS_ERROR;
   }
 
   // Share gradients for shared ABF.
@@ -355,6 +355,8 @@ void colvarbias_abf::replica_share () {
   last_gradients->copy_grid(*gradients);
   last_samples->copy_grid(*samples);
   shared_last_step = cvm::step_absolute();
+
+  return COLVARS_OK;
 }
 
 void colvarbias_abf::write_gradients_samples (const std::string &prefix, bool append)
diff --git a/lib/colvars/colvarbias_abf.h b/lib/colvars/colvarbias_abf.h
index b89ca68dec..db141db2d1 100644
--- a/lib/colvars/colvarbias_abf.h
+++ b/lib/colvars/colvarbias_abf.h
@@ -64,7 +64,7 @@ private:
   size_t   shared_freq;
   int   shared_last_step;
   // Share between replicas -- may be called independently of update
-  virtual void replica_share();
+  virtual int replica_share();
 
   // Store the last set for shared ABF
   colvar_grid_gradient  *last_gradients;
diff --git a/lib/colvars/colvarmodule.cpp b/lib/colvars/colvarmodule.cpp
index bdc44ac7aa..38506ac118 100644
--- a/lib/colvars/colvarmodule.cpp
+++ b/lib/colvars/colvarmodule.cpp
@@ -169,7 +169,7 @@ int colvarmodule::parse_global_params (std::string const &conf)
                      colvarparse::parse_silent);
 
   if (use_scripted_forces && !proxy->force_script_defined) {
-    cvm::fatal_error("User script for scripted colvars forces not found.");
+    cvm::fatal_error("User script for scripted colvar forces not found.");
   }
 
   return (cvm::get_error() ? COLVARS_ERROR : COLVARS_OK);
@@ -1303,7 +1303,7 @@ bool      colvarmodule::b_analysis = false;
 cvm::real colvarmodule::rotation::crossing_threshold = 1.0E-04;
 std::list<std::string> colvarmodule::index_group_names;
 std::list<std::vector<int> > colvarmodule::index_groups;
-
+bool     colvarmodule::use_scripted_forces = false;
 
 // file name prefixes
 std::string colvarmodule::output_prefix = "";
diff --git a/lib/colvars/colvarmodule.h b/lib/colvars/colvarmodule.h
index ad791bc375..34b3668cf8 100644
--- a/lib/colvars/colvarmodule.h
+++ b/lib/colvars/colvarmodule.h
@@ -4,7 +4,7 @@
 #define COLVARMODULE_H
 
 #ifndef COLVARS_VERSION
-#define COLVARS_VERSION "2014-10-22"
+#define COLVARS_VERSION "2014-10-23"
 #endif
 
 #ifndef COLVARS_DEBUG
@@ -468,7 +468,7 @@ protected:
   static size_t depth;
 
   /// Use scripted colvars forces?
-  bool use_scripted_forces;
+  static bool use_scripted_forces;
 
 public:
   /// \brief Pointer to the proxy object, used to retrieve atomic data
@@ -482,6 +482,8 @@ public:
 
   /// Decrease the depth (number of indentations in the output)
   static void decrease_depth();
+
+  static inline const bool scripted_forces () { return use_scripted_forces; }
 };
 
 
diff --git a/lib/colvars/colvarscript.cpp b/lib/colvars/colvarscript.cpp
index 13dffd35d1..df60e34df1 100644
--- a/lib/colvars/colvarscript.cpp
+++ b/lib/colvars/colvarscript.cpp
@@ -209,14 +209,19 @@ int colvarscript::proc_colvar (int argc, char const *argv[]) {
   std::string subcmd = argv[2];
 
   if (subcmd == "value") {
-    result = cvm::to_str(cv->value(), 0, cvm::cv_prec);
+    result = (cv->value()).to_simple_string();
+    return COLVARSCRIPT_OK;
+  }
+
+  if (subcmd == "width") {
+    result = cvm::to_str(cv->width, 0, cvm::cv_prec);
     return COLVARSCRIPT_OK;
   }
 
   if (subcmd == "update") {
     cv->calc();
     cv->update();
-    result = cvm::to_str(cv->value(), 0, cvm::cv_prec);
+    result = (cv->value()).to_simple_string();
     return COLVARSCRIPT_OK;
   }
 
@@ -234,7 +239,7 @@ int colvarscript::proc_colvar (int argc, char const *argv[]) {
 
   if (subcmd == "addforce") {
     if (argc < 4) {
-      result = "Missing parameter: force value";
+      result = "addforce: missing parameter: force value";
       return COLVARSCRIPT_ERROR;
     }
     std::string f_str = argv[3];
@@ -243,12 +248,12 @@ int colvarscript::proc_colvar (int argc, char const *argv[]) {
     is.precision(cvm::cv_prec);
     colvarvalue force (cv->type());
     force.is_derivative();
-    if (!(is >> force)) {
-      result = "Error parsing force value";
+    if (force.from_simple_string(is.str()) != COLVARS_OK) {
+      result = "addforce : error parsing force value";
       return COLVARSCRIPT_ERROR;
     }
     cv->add_bias_force(force);
-    result = cvm::to_str(force, cvm::cv_width, cvm::cv_prec);
+    result = force.to_simple_string();
     return COLVARSCRIPT_OK;
   }
 
@@ -282,6 +287,38 @@ int colvarscript::proc_bias (int argc, char const *argv[]) {
     return COLVARSCRIPT_OK;
   }
 
+  // Subcommands for MW ABF
+  if (subcmd == "bin") {
+    int r = b->current_bin();
+    if (r < 0) {
+      result = "Error: calling current_bin() for bias " + b->name;
+      return COLVARSCRIPT_ERROR;
+    }
+    result = cvm::to_str(r);
+    return COLVARSCRIPT_OK;
+  }
+
+  if (subcmd == "binnum") {
+    int r = b->bin_num();
+    if (r < 0) {
+      result = "Error: calling bin_num() for bias " + b->name;
+      return COLVARSCRIPT_ERROR;
+    }
+    result = cvm::to_str(r);
+    return COLVARSCRIPT_OK;
+  }
+
+  if (subcmd == "share") {
+    int r = b->replica_share();
+    if (r < 0) {
+      result = "Error: calling replica_share() for bias " + b->name;
+      return COLVARSCRIPT_ERROR;
+    }
+    result = cvm::to_str(r);
+    return COLVARSCRIPT_OK;
+  }
+  // End commands for MW ABF
+
   if (subcmd == "delete") {
     // the bias destructor takes care of the cleanup at cvm level
     delete b;
@@ -291,7 +328,16 @@ int colvarscript::proc_bias (int argc, char const *argv[]) {
   }
 
   if (argc >= 4) {
-//    std::string param = argv[3];
+    std::string param = argv[3];
+    if (subcmd == "count") {
+      int index;
+      if (!(std::istringstream(param) >> index)) {
+        result = "bin_count: error parsing bin index";
+        return COLVARSCRIPT_ERROR;
+      }
+      result = cvm::to_str(b->bin_count(index));
+      return COLVARSCRIPT_OK;
+    }
 
     result = "Syntax error";
     return COLVARSCRIPT_ERROR;
diff --git a/lib/colvars/colvartypes.cpp b/lib/colvars/colvartypes.cpp
index b24be512a1..a5bb42ef59 100644
--- a/lib/colvars/colvartypes.cpp
+++ b/lib/colvars/colvartypes.cpp
@@ -4,6 +4,25 @@
 #include "colvartypes.h"
 #include "colvarparse.h"
 
+std::string cvm::rvector::to_simple_string() const
+{
+  std::ostringstream os;
+  os.setf (std::ios::scientific, std::ios::floatfield);
+  os.precision(cvm::cv_prec);
+  os << x << " " << y << " " << z;
+  return os.str();
+}
+
+int cvm::rvector::from_simple_string(std::string const &s)
+{
+  std::stringstream stream(s);
+  if ( !(stream >> x) ||
+       !(stream >> y) ||
+       !(stream >> z) ) {
+    return COLVARS_ERROR;
+  }
+  return COLVARS_OK;
+}
 
 std::ostream & operator << (std::ostream &os, colvarmodule::rvector const &v)
 {
@@ -38,7 +57,26 @@ std::istream & operator >> (std::istream &is, colvarmodule::rvector &v)
   return is;
 }
 
+std::string cvm::quaternion::to_simple_string() const
+{
+  std::ostringstream os;
+  os.setf (std::ios::scientific, std::ios::floatfield);
+  os.precision(cvm::cv_prec);
+  os << q0 << " " << q1 << " " << q2 << " " << q3;
+  return os.str();
+}
 
+int cvm::quaternion::from_simple_string(std::string const &s)
+{
+  std::stringstream stream(s);
+  if ( !(stream >> q0) ||
+       !(stream >> q1) ||
+       !(stream >> q2) ||
+       !(stream >> q3) ) {
+    return COLVARS_ERROR;
+  }
+  return COLVARS_OK;
+}
 
 std::ostream & operator << (std::ostream &os, colvarmodule::quaternion const &q)
 {
diff --git a/lib/colvars/colvartypes.h b/lib/colvars/colvartypes.h
index 18a6de3cfb..281f03ceac 100644
--- a/lib/colvars/colvartypes.h
+++ b/lib/colvars/colvartypes.h
@@ -175,7 +175,8 @@ public:
     return cvm::rvector (v.x/a, v.y/a, v.z/a);
   }
 
-
+  std::string to_simple_string() const;
+  int from_simple_string(std::string const &s);
 };
 
 
@@ -639,6 +640,9 @@ public:
     return 4*real_width + 13;
   }
 
+  std::string to_simple_string() const;
+  int from_simple_string(std::string const &s);
+
   /// \brief Formatted output operator
   friend std::ostream & operator << (std::ostream &os, cvm::quaternion const &q);
   /// \brief Formatted input operator
diff --git a/lib/colvars/colvarvalue.cpp b/lib/colvars/colvarvalue.cpp
index fa209ee19d..77326e3a85 100644
--- a/lib/colvars/colvarvalue.cpp
+++ b/lib/colvars/colvarvalue.cpp
@@ -214,6 +214,51 @@ void colvarvalue::p2leg_opt(colvarvalue const                        &x,
   };
 }
 
+std::string colvarvalue::to_simple_string() const
+{
+  switch (type()) {
+  case colvarvalue::type_scalar:
+    return cvm::to_str(real_value, 0, cvm::cv_prec);
+    break;
+  case colvarvalue::type_vector:
+  case colvarvalue::type_unitvector:
+  case colvarvalue::type_unitvectorderiv:
+    return rvector_value.to_simple_string();
+    break;
+  case colvarvalue::type_quaternion:
+  case colvarvalue::type_quaternionderiv:
+    return quaternion_value.to_simple_string();
+    break;
+  case colvarvalue::type_notset:
+    undef_op();
+    break;
+  }
+  return std::string();
+}
+
+int colvarvalue::from_simple_string(std::string const &s)
+{
+  switch (type()) {
+  case colvarvalue::type_scalar:
+    return ((std::istringstream(s) >> real_value)
+            ? COLVARS_OK : COLVARS_ERROR);
+    break;
+  case colvarvalue::type_vector:
+  case colvarvalue::type_unitvector:
+  case colvarvalue::type_unitvectorderiv:
+    return rvector_value.from_simple_string(s);
+    break;
+  case colvarvalue::type_quaternion:
+  case colvarvalue::type_quaternionderiv:
+    return quaternion_value.from_simple_string(s);
+    break;
+  case colvarvalue::type_notset:
+    break;
+  default:
+    undef_op();
+  }
+  return COLVARS_ERROR;
+}
 
 std::ostream & operator << (std::ostream &os, colvarvalue const &x)
 {
diff --git a/lib/colvars/colvarvalue.h b/lib/colvars/colvarvalue.h
index 20c960259c..b5d63e79c9 100644
--- a/lib/colvars/colvarvalue.h
+++ b/lib/colvars/colvarvalue.h
@@ -287,6 +287,11 @@ public:
   /// characters for a real number
   size_t output_width(size_t const &real_width) const;
 
+  /// Formats value as a script-friendly string (space separated list)
+  std::string to_simple_string() const;
+
+  /// Parses value from a script-friendly string (space separated list)
+  int from_simple_string(std::string const &s);
 
   // optimized routines for operations with an array; xv and inner as
   // vectors are assumed to have the same number of elements (i.e. the