diff --git a/src/output/Console.php b/src/output/Console.php
new file mode 100644
index 0000000..e555126
--- /dev/null
+++ b/src/output/Console.php
@@ -0,0 +1,240 @@
+<?php
+namespace nur\sery\output;
+
+use Exception;
+use nulib\cl;
+
+class Console implements IMessenger {
+  const VALID_LEVELS = [
+    self::LEVEL_DEBUG,
+    self::LEVEL_NORMAL,
+    self::LEVEL_MAJOR,
+  ];
+  const LEVEL_MAP = [
+    "debug" => self::LEVEL_DEBUG,
+    "d" => self::LEVEL_DEBUG,
+    "normal" => self::LEVEL_NORMAL,
+    "n" => self::LEVEL_NORMAL,
+    "major" => self::LEVEL_MAJOR,
+    "m" => self::LEVEL_MAJOR,
+  ];
+
+  const TYPE_PREFIXES = [
+    self::LEVEL_MAJOR => [
+      "section" => [true, "SECTION!", "===", "<color @b>= ", " =</color>", "==="],
+      "title" => ["TITLE!", null, "<color @b>T</color><color b> ", "</color>", "---"],
+      "desc" => ["DESC!", "<color @b>></color> ", ""],
+      "error" => ["CRITICAL!", "<color @r>E! ", "</color>"],
+      "warn" => ["ATTENTION!", "<color @y>W! ", "</color>"],
+      "note" => ["IMPORTANT!", "<color @g>N! ", "</color>"],
+      "info" => ["IMPORTANT!", "<color @b>I! ", "</color>"],
+    ],
+    self::LEVEL_NORMAL => [
+      "section" => [true, "SECTION:", null, "<color @b>>> ", " <<</color>", "---"],
+      "title" => ["TITLE:", null, "<color @b>T</color><color b> ", "</color>", null],
+      "desc" => ["DESC:", "<color @b>></color> ", ""],
+      "error" => ["ERROR:", "<color @r>E</color><color r> ", "</color>"],
+      "warn" => ["WARN:", "<color @y>W</color><color y> ", "</color>"],
+      "note" => ["NOTE:", "<color @g>N</color> ", ""],
+      "info" => ["INFO:", "<color @b>I</color> ", ""],
+    ],
+    self::LEVEL_DEBUG => [
+      "section" => [false, "s", null, "<color @w>>> ", " <<</color>", null],
+      "title" => ["t", "<color b>t ", "</color>"],
+      "desc" => [">", "<color b>></color> ", ""],
+      "error" => ["e", "<color r>e</color><color -r> ", "</color>"],
+      "warn" => ["w", "<color y>w</color><color -y> ", "</color>"],
+      "note" => ["i", "<color b>i</color> ", ""],
+      "info" => ["D", "<color @w>D</color><color w> ", "</color>"],
+    ],
+  ];
+
+  const RESULT_PREFIXES = [
+    "step" => ["*", "<color @w>.</color>"],
+    "failure" => ["(FAILURE)", "<color r>✘</color>"],
+    "success" => ["(SUCCESS)", "<color @g>✔</color>"],
+    "neutral" => [null, null],
+  ];
+
+  function __construct(?array $params=null) {
+    $debug = boolval(cl::get($params, "debug"));
+    $minLevel = cl::get($params, "min_level");
+    if ($minLevel === null) $minLevel = $debug? self::LEVEL_DEBUG: self::LEVEL_NORMAL;
+    if (!in_array($minLevel, self::VALID_LEVELS)) {
+      $minLevel = cl::get(self::LEVEL_MAP, $minLevel, $minLevel);
+    }
+    if (!in_array($minLevel, self::VALID_LEVELS)) {
+      throw new Exception("$minLevel: invalid level");
+    }
+
+    $this->out = new StdOutput(STDOUT);
+    $this->err = new StdOutput(STDERR);
+    $this->minLevel = intval($minLevel);
+    $this->pending = [];
+    $this->inSection = false;
+    $this->titles = null;
+    $this->actions = null;
+  }
+
+  /** @var StdOutput la sortie standard */
+  protected $out;
+
+  /** @var StdOutput la sortie d'erreur */
+  protected $err;
+
+  /** @var int level minimum que doivent avoir les messages pour être affichés */
+  protected $minLevel;
+
+  /** @var bool est-on dans une section? */
+  protected $inSection;
+
+  /** @var array|string section qui est en attente d'affichage */
+  protected $section;
+
+  function section($content, int $level=self::LEVEL_NORMAL): void {
+    $this->endSection();
+    $this->inSection = true;
+    if ($level < $this->minLevel) return;
+    $this->section = $content;
+  }
+
+  protected function printSection() {
+    if ($this->section !== null) {
+      $this->section = null;
+    }
+  }
+
+  protected function endSection(): void {
+    $this->inSection = false;
+    $this->section = null;
+  }
+
+  /** @var array */
+  protected $titles;
+
+  /** @var array */
+  protected $currentTitle;
+
+  function title($content, int $level=self::LEVEL_NORMAL): void {
+    if ($level < $this->minLevel) return;
+    $this->titles[] = [
+      "title" => $content, 
+      "descs" => [],
+      "print" => true, 
+    ];
+    $this->currentTitle =& $this->titles[count($this->titles) - 1];
+  }
+
+  function desc($content, int $level=self::LEVEL_NORMAL): void {
+    if ($level < $this->minLevel) return;
+    $this->currentTitle["descs"][] = $content;
+  }
+
+  protected function printTitles(): void {
+    $this->printSection();
+  }
+
+  protected function endTitle(): void {
+    array_pop($this->titles);
+    if ($this->titles) {
+      $this->currentTitle =& $this->titles[count($this->titles) - 1];
+    } else {
+      unset($this->currentTitle);
+    }
+  }
+
+  function print($content, int $level=self::LEVEL_NORMAL): void {
+    if ($level < $this->minLevel) return;
+    $this->printTitles();
+    $this->out->print($content);
+  }
+
+  /** @var array */
+  protected $actions;
+  
+  /** @var array */
+  protected $currentAction;
+
+  function action($content, int $level=self::LEVEL_NORMAL): void {
+    $this->actions[] = [
+      "level" => $level,
+      "contents" => [$content],
+      "result" => null,
+      "print" => true,
+    ];
+    $this->currentAction =& $this->actions[count($this->actions) - 1];
+  }
+  
+  function printActions(): void {
+    $this->printTitles();
+    
+  }
+
+  function step($content): void {
+    $this->printActions();
+  }
+
+  function success($content=null): void {
+    $this->currentAction["contents"][] = $content;
+    $this->currentAction["result"] = true;
+    $this->printActions();
+    $this->endAction();
+  }
+
+  function failure($content=null): void {
+    $this->currentAction["contents"][] = $content;
+    $this->currentAction["result"] = false;
+    $this->printActions();
+    $this->endAction();
+  }
+
+  function neutral($content=null): void {
+    $this->currentAction["contents"][] = $content;
+    $this->currentAction["result"] = null;
+    $this->printActions();
+    $this->endAction();
+  }
+
+  protected function endAction(): void {
+    array_pop($this->actions);
+    if ($this->actions) {
+      $this->currentAction =& $this->actions[count($this->actions) - 1];
+    } else {
+      unset($this->currentAction);
+    }
+  }
+
+  function info($content, int $level=self::LEVEL_NORMAL): void {
+    if ($level < $this->minLevel) return;
+    $this->printActions();
+  }
+
+  function note($content, int $level=self::LEVEL_NORMAL): void {
+    if ($level < $this->minLevel) return;
+    $this->printActions();
+  }
+
+  function warn($content, int $level=self::LEVEL_NORMAL): void {
+    if ($level < $this->minLevel) return;
+    $this->printActions();
+  }
+
+  function error($content, int $level=self::LEVEL_NORMAL): void {
+    if ($level < $this->minLevel) return;
+    $this->printActions();
+  }
+
+  function end(bool $all=false) {
+    if ($all) {
+      while ($this->actions) $this->neutral();
+      while ($this->titles) $this->endTitle();
+      $this->endSection();
+    } elseif ($this->actions) {
+      $this->endAction();
+    } elseif ($this->titles) {
+      $this->endTitle();
+    } else {
+      $this->endSection();
+    }
+  }
+}
diff --git a/src/output/IMessenger.php b/src/output/IMessenger.php
new file mode 100644
index 0000000..1f33b36
--- /dev/null
+++ b/src/output/IMessenger.php
@@ -0,0 +1,87 @@
+<?php
+namespace nur\sery\output;
+
+/**
+ * Interface IMessenger: un objet pouvant afficher des messages de l'application
+ */
+interface IMessenger {
+  const LEVEL_DEBUG = -1, LEVEL_NORMAL = 0, LEVEL_MAJOR = 1;
+
+  /**
+   * commencer une section.
+   *
+   * flush tous les messages en cours. ne peut être imbriqué. on peut considérer
+   * que c'est une sorte de "reset" de l'objet
+   */
+  function section($content, int $level=self::LEVEL_NORMAL): void;
+
+  /**
+   * commencer un chapitre.
+   *
+   * peut être imbriqué dans un autre chapitre. terminer automatiquement
+   * l'action en cours avec un résultat neutre
+   */
+  function title($content, int $level=self::LEVEL_NORMAL): void;
+
+  /** ajouter une description au chapitre courant. */
+  function desc($content, int $level=self::LEVEL_NORMAL): void;
+
+  /** afficher une donnée non structurée dans la chapitre courant */
+  function print($content, int $level=self::LEVEL_NORMAL): void;
+
+  /**
+   * comencer une action dans le chapitre courant.
+   *
+   * peut être imbriqué dans une autre action.
+   */
+  function action($content, int $level=self::LEVEL_NORMAL): void;
+
+  /**
+   * ajouter une étape à l'action courante.
+   *
+   * démarrer une action le cas échéant (et la terminer aussitôt)
+   */
+  function step($content): void;
+
+  /**
+   * terminer l'action courante avec le résultat "succès"
+   *
+   * démarrer une action le cas échéant (et la terminer aussitôt)
+   */
+  function success($content=null): void;
+
+  /**
+   * terminer l'action courante avec le résultat "échec"
+   *
+   * démarrer une action le cas échéant (et la terminer aussitôt)
+   */
+  function failure($content=null): void;
+
+  /**
+   * terminer l'action courante avec le résultat "neutre"
+   *
+   * démarrer une action le cas échéant (et la terminer aussitôt)
+   */
+  function neutral($content=null): void;
+
+  /** ajouter un événément "information" */
+  function info($content, int $level=self::LEVEL_NORMAL): void;
+
+  /** ajouter un événément "information importante" */
+  function note($content, int $level=self::LEVEL_NORMAL): void;
+
+  /** ajouter un événément "avertissement" */
+  function warn($content, int $level=self::LEVEL_NORMAL): void;
+
+  /** ajouter un événément "erreur" */
+  function error($content, int $level=self::LEVEL_NORMAL): void;
+
+  /**
+   * terminer le chapitre en cours. toutes les actions en cours sont terminées
+   * avec un résultat neutre.
+   *
+   * @param bool $all faut-il terminer *tous* les chapitres ainsi que la section
+   * en cours?
+   */
+  function end(bool $all=false);
+}
diff --git a/src/output/StdOutput.php b/src/output/StdOutput.php
new file mode 100644
index 0000000..b548f7e
--- /dev/null
+++ b/src/output/StdOutput.php
@@ -0,0 +1,178 @@
+<?php
+namespace nur\sery\output;
+
+use Exception;
+use nulib\cl;
+
+/**
+ * Class StdOutput: affichage sur STDOUT, STDERR ou dans un fichier quelconque
+ *
+ * si la destination est un fichier, aucune gestion d'erreur n'est faite, sauf
+ * lors de l'ouverture.
+ */
+class StdOutput {
+  const COLORS = [
+    "reset" => "0",
+    "bold" => "1",
+    "faint" => "2",
+    "underlined" => "4",
+    "reverse" => "7",
+    "normal" => "22",
+    "black" => "30",
+    "red" => "31",
+    "green" => "32",
+    "yellow" => "33",
+    "blue" => "34",
+    "magenta" => "35",
+    "cyan" => "36",
+    "white" => "37",
+    "default" => "39",
+    "black-bg" => "40",
+    "red-bg" => "41",
+    "green-bg" => "42",
+    "yellow-bg" => "43",
+    "blue-bg" => "44",
+    "magenta-bg" => "45",
+    "cyan-bg" => "46",
+    "white-bg" => "47",
+    "default-bg" => "49",
+  ];
+
+  const COLOR_MAP = [
+    "z" => "reset",
+    "o" => "black",
+    "r" => "red",
+    "g" => "green",
+    "y" => "yellow",
+    "b" => "blue",
+    "m" => "magenta",
+    "c" => "cyan",
+    "w" => "white",
+    "O" => "black_bg",
+    "R" => "red_bg",
+    "G" => "green_bg",
+    "Y" => "yellow_bg",
+    "B" => "blue_bg",
+    "M" => "magenta_bg",
+    "C" => "cyan_bg",
+    "W" => "white_bg",
+    "@" => "bold",
+    "-" => "faint",
+    "_" => "underlined",
+    "~" => "reverse",
+    "n" => "normal",
+  ];
+
+  /**
+   * @param resource|null $outf
+   * @throws Exception si la destination est un fichier et que son ouverture a
+   * échoué
+   */
+  function __construct($output=null, ?array $params=null) {
+    if ($output === null) $output = cl::get($params, "output");
+    $color = cl::get($params, "color");
+    $filterTags = cl::get($params, "filter_tags", true);
+    $flush = cl::get($params, "flush");
+
+    if ($output === null) {
+      $outf = STDOUT;
+    } elseif ($output === "php://stdout") {
+      $outf = STDOUT;
+    } elseif ($output === "php://stderr") {
+      $outf = STDERR;
+    } elseif (!is_resource($output)) {
+      # si $outf est un nom de fichier, vérifier que l'ouverture se fait sans
+      # erreur. à partir de là, plus aucune gestion d'erreur n'est faite
+      $outf = @fopen($output, "ab");
+      if ($outf === false) {
+        $error = error_get_last();
+        if ($error !== null) $message = $error["message"];
+        else $message = "$output: open error";
+        throw new Exception($message);
+      }
+      if ($flush === null) $flush = true;
+    } else {
+      $outf = $output;
+    }
+    if ($color === null) $color = stream_isatty($outf);
+    if ($flush === null) $flush = false;
+
+    $this->outf = $outf;
+    $this->color = boolval($color);
+    $this->filterTags = boolval($filterTags);
+    $this->flush = boolval($flush);
+  }
+
+  /** @var resource  */
+  protected $outf;
+
+  /** @var bool faut-il autoriser la sortie en couleur? */
+  protected $color;
+
+  function isColor(): bool {
+    return $this->color;
+  }
+
+  /** @var bool faut-il enlever les tags dans la sortie? */
+  protected $filterTags;
+
+  /** @var bool faut-il flush le fichier après l'écriture de chaque ligne */
+  protected $flush;
+
+  function isatty(): bool {
+    return stream_isatty($this->outf);
+  }
+
+  private static function replace_colors(array $ms): string {
+    $colors = [];
+    foreach (preg_split('/\s+/', $ms[1]) as $color) {
+      while ($color && !cl::has(self::COLORS, $color)) {
+        $alias = substr($color, 0, 1);
+        $colors[] = self::COLOR_MAP[$alias];
+        $color = substr($color, 1);
+      }
+      if ($color) $colors[] = $color;
+    }
+    $text = "\x1B[";
+    $first = true;
+    foreach ($colors as $color) {
+      if (!$color) continue;
+      if ($first) $first = false;
+      else $text .= ";";
+      $text .= self::COLORS[$color];
+    }
+    $text .= "m";
+    return $text;
+  }
+  protected function filterContent(string $text): string {
+    # couleur au début
+    $text = preg_replace_callback('/<color([^>]*)>/', [self::class, "replace_colors"], $text);
+    # reset à la fin
+    $text = preg_replace('/<\/color>/', "\x1B[0m", $text);
+    # enlever les tags classiques
+    if ($this->filterTags) {
+      $text = preg_replace('/<[^>]*>/', "", $text);
+    }
+    return $text;
+  }
+  protected function filterColors(string $text): string {
+    return preg_replace('/\x1B\[.*?m/', "", $text);
+  }
+
+  protected function fwrite(array $values): void {
+    $text = implode("", $values);
+    $text = $this->filterContent($text);
+    if (!$this->color) $text = $this->filterColors($text);
+    fwrite($this->outf, $text);
+    if ($this->flush) fflush($this->outf);
+  }
+
+  function write(...$values): void {
+    $this->fwrite($values);
+  }
+
+  function print(...$values): void {
+    $values[] = "\n";
+    $this->fwrite($values);
+  }
+}
diff --git a/src/output/msg/TODO.md b/src/output/TODO.md
similarity index 98%
rename from src/output/msg/TODO.md
rename to src/output/TODO.md
index 959bbb5..a8cd04d 100644
--- a/src/output/msg/TODO.md
+++ b/src/output/TODO.md
@@ -1,4 +1,4 @@
-# msg
+# IMessenger
 
 * 3 niveaux: DEBUG, NORMAL, MAJOR
 * plusieurs types de messages: