diff --git a/nur_src/cli/Application.php b/nur_src/cli/Application.php
index 10aa950..f48919d 100644
--- a/nur_src/cli/Application.php
+++ b/nur_src/cli/Application.php
@@ -16,7 +16,7 @@ use nur\path;
 abstract class Application {
   protected static function _app_init(): void {
     config::set_fact(config::FACT_CLI_APP);
-    \nulib\output\msg::set_messenger_class(\nulib\output\std\StdMessenger::class);
+    \nur\sery\output\msg::set_messenger_class(\nur\sery\output\std\StdMessenger::class);
 
     msg::set_messenger_class(Console::class);
     msg::get()->setParametrableParams([
diff --git a/src/DataException.php b/src/DataException.php
deleted file mode 100644
index ec4089e..0000000
--- a/src/DataException.php
+++ /dev/null
@@ -1,19 +0,0 @@
-<?php
-namespace nur\sery;
-
-use RuntimeException;
-
-/**
- * Class DataException: exception générique concernant l'accès à des données
- */
-class DataException extends RuntimeException {
-  static final function no_more_data(): self {
-    return new self("no more data");
-  }
-
-  static final function ensure_not_eof($data, bool $throw=true, $eof=false) {
-    if (!$throw) return null;
-    elseif ($data !== $eof) return $data;
-    else throw self::no_more_data();
-  }
-}
diff --git a/src/NoMoreDataException.php b/src/NoMoreDataException.php
new file mode 100644
index 0000000..eb8199a
--- /dev/null
+++ b/src/NoMoreDataException.php
@@ -0,0 +1,10 @@
+<?php
+namespace nur\sery;
+
+use RuntimeException;
+
+/**
+ * Class NoMoreDataException: indiquer que plus aucune donnée n'est disponible
+ */
+class NoMoreDataException extends RuntimeException {
+}
diff --git a/src/os/EOFException.php b/src/os/EOFException.php
index 2754139..8f8e2ea 100644
--- a/src/os/EOFException.php
+++ b/src/os/EOFException.php
@@ -6,13 +6,9 @@ namespace nur\sery\os;
  * flux
  */
 class EOFException extends IOException {
-  static final function no_more_data(): self {
-    return new self("no more data");
-  }
-
   static final function ensure_not_eof($data, bool $throw=true, $eof=false) {
     if (!$throw) return null;
     elseif ($data !== $eof) return $data;
-    else throw self::no_more_data();
+    else throw new self();
   }
 }
diff --git a/src/os/file/Stream.php b/src/os/file/Stream.php
index 935b571..44cb479 100644
--- a/src/os/file/Stream.php
+++ b/src/os/file/Stream.php
@@ -1,11 +1,12 @@
 <?php
 namespace nur\sery\os\file;
 
-use nur\sery\str;
-use nur\sery\ValueException;
+use nur\sery\NoMoreDataException;
 use nur\sery\os\EOFException;
 use nur\sery\os\IOException;
 use nur\sery\php\iter\AbstractIterator;
+use nur\sery\str;
+use nur\sery\ValueException;
 
 /**
  * Class Stream: lecture/écriture générique dans un flux
@@ -149,7 +150,9 @@ class Stream extends AbstractIterator implements IReader, IWriter {
    */
   function fgets(?int $length=null): string {
     $fd = $this->getResource();
-    return EOFException::ensure_not_eof(fgets($fd, $length), $this->throwOnError);
+    if ($length === null) $r = fgets($fd);
+    else $r = fgets($fd, $length);
+    return EOFException::ensure_not_eof($r, $this->throwOnError);
   }
 
   /** @throws IOException */
@@ -234,11 +237,16 @@ class Stream extends AbstractIterator implements IReader, IWriter {
   }
 
   protected function _next(&$key) {
-    return $this->fgets();
+    try {
+      return $this->fgets();
+    } catch (EOFException $e) {
+      throw new NoMoreDataException();
+    }
   }
 
   protected function _teardown(): void {
-    $this->fseek(0);
+    $md = stream_get_meta_data($this->fd);
+    if ($md["seekable"]) $this->fseek(0);
   }
 
   #############################################################################
diff --git a/src/output/out.php b/src/output/out.php
new file mode 100644
index 0000000..7430935
--- /dev/null
+++ b/src/output/out.php
@@ -0,0 +1,33 @@
+<?php
+namespace nur\sery\output;
+
+use nur\sery\output\std\StdOutput;
+
+/**
+ * Class out: affichage sur la sortie standard
+ */
+class out {
+  /** @var StdOutput */
+  protected static $out;
+
+  /** reparamétrer l'instance */
+  static function reset($output=null, ?array $params=null): StdOutput {
+    if (self::$out === null) {
+      return self::$out = new StdOutput($output, $params);
+    }
+    if ($output !== null) $params["output"] = $output;
+    self::$out->resetParams($params);
+    return self::$out;
+  }
+
+  static function get(): StdOutput {
+    if (self::$out !== null) return self::$out;
+    else return self::reset();
+  }
+
+  static function write(...$values): void { self::get()->write(...$values); }
+  static function print(...$values): void { self::get()->print(...$values); }
+
+  static function iwrite(int $indentLevel, ...$values): void { self::get()->iwrite($indentLevel, ...$values); }
+  static function iprint(int $indentLevel, ...$values): void { self::get()->iprint($indentLevel, ...$values); }
+}
diff --git a/src/php/iter/AbstractIterator.php b/src/php/iter/AbstractIterator.php
index ef11844..b74e24e 100644
--- a/src/php/iter/AbstractIterator.php
+++ b/src/php/iter/AbstractIterator.php
@@ -3,7 +3,7 @@ namespace nur\sery\php\iter;
 
 use Exception;
 use Iterator;
-use nur\sery\DataException;
+use nur\sery\NoMoreDataException;
 use nur\sery\php\ICloseable;
 
 /**
@@ -29,12 +29,13 @@ abstract class AbstractIterator implements Iterator, ICloseable {
   protected function beforeIter() {}
 
   /**
-   * retourner le prochain élément. lancer l'exception {@link DataException} pour
-   * indiquer que plus aucun élément n'est disponible
+   * retourner le prochain élément.
+   * lancer l'exception {@link NoMoreDataException} pour indiquer que plus aucun
+   * élément n'est disponible
    *
    * le cas échéant, initialiser $key
    *
-   * @throws DataException
+   * @throws NoMoreDataException
    */
   abstract protected function _next(&$key);
 
@@ -94,7 +95,7 @@ abstract class AbstractIterator implements Iterator, ICloseable {
     $this->valid = false;
     try {
       $item = $this->_next($key);
-    } catch (DataException $e) {
+    } catch (NoMoreDataException $e) {
       $this->beforeClose();
       try {
         $this->_teardown();