diff --git a/artefact.inc.php b/artefact.inc.php
index 4406cda..bd8d2fb 100644
--- a/artefact.inc.php
+++ b/artefact.inc.php
@@ -111,7 +111,7 @@ class TaskmanArtefact
             $changed = array();
             foreach($src_spec[0] as $spec_dir)
             {
-              $matches = $file_changes->matchDirectory($spec_dir);
+              $matches = $file_changes->matchDirectory($spec_dir, $src_spec[1]);
               $changed[$spec_dir] = $matches;
             }
             return new TaskmanDirFiles($changed);
@@ -162,6 +162,11 @@ class TaskmanDirFiles implements \ArrayAccess, \Countable, \Iterator
       $this->dir2files[$dir] = $files;
   }
 
+  function __toString() : string
+  {
+    return var_export($this->dir2files, true);
+  }
+
   function toMap() : array
   {
     return $this->dir2files;
diff --git a/internal.inc.php b/internal.inc.php
index 8c5bb64..8d8cf4d 100644
--- a/internal.inc.php
+++ b/internal.inc.php
@@ -166,7 +166,7 @@ function _read_env_vars()
   }
 }
 
-function _process_argv(&$argv)
+function _process_argv(array &$argv)
 {
   global $TASKMAN_LOG_LEVEL;
   global $TASKMAN_BATCH;
@@ -253,3 +253,32 @@ function _process_argv(&$argv)
   $argv = $filtered;
 }
 
+function _extract_lines_from_file(string $file_path) : array
+{
+  $lines = array();
+
+  $fh = fopen($file_path, 'r+');
+
+  if($fh === false)
+    return $lines;
+
+  try
+  {
+    if(flock($fh, LOCK_EX))
+    {
+      while(($line = fgets($fh)) !== false)
+        $lines[] = $line;
+
+      ftruncate($fh, 0);
+
+      flock($fh, LOCK_UN);
+    }
+  }
+  finally
+  {
+    fclose($fh);
+  }
+
+  return $lines;
+}
+
diff --git a/taskman.inc.php b/taskman.inc.php
index 85f25ec..0db8bce 100644
--- a/taskman.inc.php
+++ b/taskman.inc.php
@@ -181,7 +181,7 @@ class TaskmanTask
 
       $level = count($TASKMAN_STACK)-1; 
 
-      msg_sys("***** ".str_repeat('-', $level)."task '" . $this->getName() . "' start *****\n");
+      log(0, "***** ".str_repeat('-', $level)."task '" . $this->getName() . "' start *****\n");
 
       if(!$TASKMAN_NO_DEPS)
       {
@@ -199,7 +199,7 @@ class TaskmanTask
       if(!$TASKMAN_NO_DEPS)
         run_many($this->after_deps);
 
-      msg_sys("***** ".str_repeat('-', $level)."task '" . $this->getName() . "' done(" . 
+      log(0, "***** ".str_repeat('-', $level)."task '" . $this->getName() . "' done(" . 
                      round(microtime(true)-$bench,2) . '/' .round(microtime(true)-$TASKMAN_START_TIME,2) . " sec.) *****\n");
 
       $this->has_run[$args_str] = true;
@@ -279,7 +279,7 @@ class TaskmanTask
 
       if($artefact->isStale())
       {
-        msg_sys("Task '{$this->name}' artefact '{$artefact->getPath()}' (sources at ".implode(',', $artefact->getNewerSourcesIndices()).") is stale\n");
+        log(0, "Task '{$this->name}' artefact '{$artefact->getPath()}' (sources at ".implode(',', $artefact->getNewerSourcesIndices()).") is stale\n");
       }
     }
 
@@ -299,28 +299,35 @@ class TaskmanTask
 
 class TaskmanFileChanges
 {
+  const Changed = 1;
+  const Created = 2;
+  const Renamed = 3;
+  const Deleted = 4;
+
+  //file => status
   private $changed = array();
-  private $removed = array();
 
   static function parse(string $json_or_file)
   {
     if($json_or_file[0] == '[')
       $json = $json_or_file;
     else
-      $json = file_get_contents($json_or_file);
+    {
+      $lines = internal\_extract_lines_from_file($json_or_file);
+      $json = '[' . implode(',', $lines) . ']';
+    }
 
     $decoded = json_decode($json, true);
     if(!is_array($decoded))
-      throw new Exception('Bad json');
+      throw new Exception('Bad json: ' . $json);
 
     $changed = array();
-    $removed = array();
 
     $base_dir = dirname($_SERVER['PHP_SELF']);
 
     foreach($decoded as $items)
     {
-      if(count($items) != 2)
+      if(count($items) < 2)
         throw new Exception('Bad entry');
       list($status, $file) = $items; 
 
@@ -337,30 +344,33 @@ class TaskmanFileChanges
 
       $file = artefact\normalize_path($file);
 
-      if($status == 'C')
-        $changed[$file] = true;
-      else if($status == 'R')
-        $removed[$file] = true;
+      if($status == 'Changed')
+        $changed[$file] = self::Changed;
+      else if($status == 'Created')
+        $changed[$file] = self::Created;
+      else if($status == 'Renamed')
+        $changed[$file] = self::Renamed;
+      else if($status == 'Deleted')
+        $changed[$file] = self::Deleted;
       else 
         throw new Exception('Unknown status: ' . $status);
     }
 
-    return new TaskmanFileChanges($changed, $removed);
+    return new TaskmanFileChanges($changed);
   } 
 
-  //NOTE: these are actually maps: file => true
-  function __construct(array $changed, array $removed)
+  //NOTE: maps: file => status
+  function __construct(array $changed)
   {
     $this->changed = $changed;
-    $this->removed = $removed;
   }
 
   function isEmpty() : bool
   {
-    return count($this->changed) == 0 && count($this->removed) == 0;
+    return count($this->changed) == 0;
   }
 
-  function matchDirectory(string $dir) : array
+  function matchDirectory(string $dir, array $extensions = array()) : array
   {
     $dir = rtrim($dir, '/\\');
     $dir .= DIRECTORY_SEPARATOR;
@@ -368,25 +378,118 @@ class TaskmanFileChanges
     $filtered = [];
 
     foreach($this->changed as $path => $_)
-      if(strpos($path, $dir) === 0)
-        $filtered[] = $path;
-
-    foreach($this->removed as $path => $_)
-      if(strpos($path, $dir) === 0)
+      if(self::matchDirAndExtension($path, $dir, $extensions))
         $filtered[] = $path;
 
     return $filtered;
   }
 
+  static function matchDirAndExtension(string $path, string $dir, array $extensions) : bool
+  {
+    if(strpos($path, $dir) !== 0)
+      return false;
+
+    foreach($extensions as $ext)
+      if(!str_ends_with($path, $ext))
+        return false;
+
+    return true;
+  }
+
   function matchFiles(iterable $files) : array
   {
     $filtered = [];
     foreach($files as $file)
     {
-      if(isset($this->changed[$file]) || isset($this->removed[$file]))
+      if(isset($this->changed[$file]))
         $filtered[] = $file;
     }
     return $filtered;
   }
 }
 
+function main(
+  array $argv = array(), 
+  callable $help_func = null, 
+  bool $proc_argv = true, 
+  bool $read_env_vars = true
+)
+{
+  $GLOBALS['TASKMAN_START_TIME'] = microtime(true);
+
+  if($help_func)
+    $GLOBALS['TASKMAN_HELP_FUNC'] = $help_func;
+
+  if($read_env_vars)
+    internal\_read_env_vars();
+
+  if($proc_argv)
+    internal\_process_argv($argv);
+
+  $GLOBALS['TASKMAN_SCRIPT'] = array_shift($argv);
+
+  internal\_collect_tasks();
+
+  $always_tasks = array();
+  $default_task = null;
+  foreach(get_tasks() as $task_obj)
+  {
+    if($task_obj->hasProp('always'))
+      array_unshift($always_tasks, $task_obj);
+    if($task_obj->hasProp('default'))
+    {
+      if($default_task)
+        throw new TaskmanException("Assigned default task '" . $default_task->getName() . "' conflicts with '" . $task_obj->getName() . "'");
+      else
+        $default_task = $task_obj;
+    }
+  }
+
+  foreach($always_tasks as $always_task)
+    run($always_task);
+
+  if(sizeof($argv) > 0)
+  {
+    $task_str = array_shift($argv);
+    $tasks = internal\_parse_taskstr($task_str);
+
+    if(count($tasks) == 1 && !internal\_isset_task($tasks[0]))
+    {
+      $pattern = $tasks[0];
+      if($pattern[0] == '~')
+      {
+        $pattern = substr($pattern, 1, strlen($pattern) - 1);
+        $is_similar = true;
+      }
+      elseif(substr($pattern, -1, 1) == '~')
+      {
+        $pattern = substr($pattern, 0, strlen($pattern) - 1);
+        $is_similar = true;
+      }
+      else
+        $is_similar = false;
+      $hints = internal\_get_hints($pattern);
+
+      if($is_similar && count($hints) == 1)
+        $tasks = $hints;
+      else
+      {
+        printf("ERROR! Task %s not found\n", $tasks[0]);
+        if($hints)
+        {
+          printf("Similar tasks:\n");
+          foreach($hints as $hint)
+            printf("    %s\n", $hint);
+        }
+        exit(1);
+      }
+    }
+
+    run_many($tasks, $argv);
+  }
+  else if($default_task)
+    run($default_task, $argv);
+
+  log(0, "***** All done (".round(microtime(true)-$GLOBALS['TASKMAN_START_TIME'],2)." sec.) *****\n");
+}
+
diff --git a/util.inc.php b/util.inc.php
index f880366..91a082d 100644
--- a/util.inc.php
+++ b/util.inc.php
@@ -163,86 +163,6 @@ function _(string $str) : string
   return $str;
 }
 
-function main($argv = array(), $help_func = null, $proc_argv = true, $read_env_vars = true)
-{
-  $GLOBALS['TASKMAN_START_TIME'] = microtime(true);
-
-  if($help_func)
-    $GLOBALS['TASKMAN_HELP_FUNC'] = $help_func;
-
-  if($read_env_vars)
-    internal\_read_env_vars();
-
-  if($proc_argv)
-    internal\_process_argv($argv);
-
-  $GLOBALS['TASKMAN_SCRIPT'] = array_shift($argv);
-
-  internal\_collect_tasks();
-
-  $always_tasks = array();
-  $default_task = null;
-  foreach(get_tasks() as $task_obj)
-  {
-    if($task_obj->hasProp('always'))
-      array_unshift($always_tasks, $task_obj);
-    if($task_obj->hasProp('default'))
-    {
-      if($default_task)
-        throw new TaskmanException("Assigned default task '" . $default_task->getName() . "' conflicts with '" . $task_obj->getName() . "'");
-      else
-        $default_task = $task_obj;
-    }
-  }
-
-  foreach($always_tasks as $always_task)
-    run($always_task);
-
-  if(sizeof($argv) > 0)
-  {
-    $task_str = array_shift($argv);
-    $tasks = internal\_parse_taskstr($task_str);
-
-    if(count($tasks) == 1 && !internal\_isset_task($tasks[0]))
-    {
-      $pattern = $tasks[0];
-      if($pattern[0] == '~')
-      {
-        $pattern = substr($pattern, 1, strlen($pattern) - 1);
-        $is_similar = true;
-      }
-      elseif(substr($pattern, -1, 1) == '~')
-      {
-        $pattern = substr($pattern, 0, strlen($pattern) - 1);
-        $is_similar = true;
-      }
-      else
-        $is_similar = false;
-      $hints = internal\_get_hints($pattern);
-
-      if($is_similar && count($hints) == 1)
-        $tasks = $hints;
-      else
-      {
-        printf("ERROR! Task %s not found\n", $tasks[0]);
-        if($hints)
-        {
-          printf("Similar tasks:\n");
-          foreach($hints as $hint)
-            printf("    %s\n", $hint);
-        }
-        exit(1);
-      }
-    }
-
-    run_many($tasks, $argv);
-  }
-  else if($default_task)
-    run($default_task, $argv);
-
-  msg_sys("***** All done (".round(microtime(true)-$GLOBALS['TASKMAN_START_TIME'],2)." sec.) *****\n");
-}
-
 function usage($script_name = "<taskman-script>")
 {
   internal\_default_usage($script_name);