diff --git a/src/main/java/ru/dmitriymx/shell/Formatter.java b/src/main/java/ru/dmitriymx/shell/Formatter.java
new file mode 100644
index 0000000..8b5f96e
--- /dev/null
+++ b/src/main/java/ru/dmitriymx/shell/Formatter.java
@@ -0,0 +1,9 @@
+package ru.dmitriymx.shell;
+
+/**
+ * @author DmitriyMX <mail@dmitriymx.ru>
+ *         2015
+ */
+public interface Formatter {
+    String format(String s);
+}
diff --git a/src/main/java/ru/dmitriymx/shell/Shell.java b/src/main/java/ru/dmitriymx/shell/Shell.java
index f7ad70f..a55401a 100644
--- a/src/main/java/ru/dmitriymx/shell/Shell.java
+++ b/src/main/java/ru/dmitriymx/shell/Shell.java
@@ -71,6 +71,10 @@ public class Shell {
         return run;
     }
 
+    public void setFormatter(Formatter formatter) {
+        newErr.setFormatter(formatter);
+    }
+
     /**
      * Подмена стандартных SysErr и SysOut
      */
diff --git a/src/main/java/ru/dmitriymx/shell/ShellPrintStream.java b/src/main/java/ru/dmitriymx/shell/ShellPrintStream.java
index a7ebfbe..fbc12f6 100644
--- a/src/main/java/ru/dmitriymx/shell/ShellPrintStream.java
+++ b/src/main/java/ru/dmitriymx/shell/ShellPrintStream.java
@@ -16,6 +16,7 @@ import java.io.PrintWriter;
 public class ShellPrintStream extends PrintStream {
     private ConsoleReader consoleReader;
     private PrintWriter writer;
+    private Formatter formatter;
 
     public ShellPrintStream(OutputStream outputStream) {
         super(outputStream, true);
@@ -29,6 +30,10 @@ public class ShellPrintStream extends PrintStream {
         }
     }
 
+    public void setFormatter(Formatter formatter) {
+        this.formatter = formatter;
+    }
+
     @Override
     public void print(String s) {
         println(s);
@@ -38,7 +43,11 @@ public class ShellPrintStream extends PrintStream {
     public void println(String s) {
         if (consoleReader != null) {
             writer.print(ConsoleReader.RESET_LINE);
-            writer.print(s);
+            if (formatter != null) {
+                writer.print(formatter.format(s));
+            } else {
+                writer.print(s);
+            }
             cleanTrashLine(s);
             writer.println();
             try {
@@ -49,7 +58,11 @@ public class ShellPrintStream extends PrintStream {
             writer.flush();
         } else {
             super.print(ConsoleReader.RESET_LINE);
-            super.print(s);
+            if (formatter != null) {
+                super.print(formatter.format(s));
+            } else {
+                super.print(s);
+            }
         }
     }