diff --git a/README.md b/README.md
index b400bee..8a541f3 100644
--- a/README.md
+++ b/README.md
@@ -7,7 +7,6 @@ Jedis was conceived to be EASY to use and FULLY COMPATIBLE with the latest versi
 Jedis is a WORK IN PROGRESS.
 
 ## What's still missing?
-- Commands operating on string values
 - Commands operating on lists
 - Commands operating on sets
 - Commands operating on sorted sets
@@ -24,7 +23,7 @@ But stay close because things are going fast and all this will be implemented so
 ## Ok.. so what's already done?
 - Connection handling (not AUTH)
 - Commands operating on all the kind of values
-- Commands operating on string values (just GET and SET)
+- Commands operating on string values
 
 ## How do I use it?
 
diff --git a/src/main/java/redis/clients/jedis/Jedis.java b/src/main/java/redis/clients/jedis/Jedis.java
index 59ce924..c4619fa 100644
--- a/src/main/java/redis/clients/jedis/Jedis.java
+++ b/src/main/java/redis/clients/jedis/Jedis.java
@@ -44,7 +44,7 @@ public class Jedis extends Client {
     }
 
     public String randomKey() throws JedisException {
-	return sendCommand("RANDOMKEY").getStatusCodeReply();
+	return sendCommand("RANDOMKEY").getBulkReply();
     }
 
     public String rename(String oldkey, String newkey) throws JedisException {
@@ -86,4 +86,57 @@ public class Jedis extends Client {
     public String flushAll() throws JedisException {
 	return sendCommand("FLUSHALL").getStatusCodeReply();
     }
+
+    public String getSet(String key, String value) throws JedisException {
+	return sendCommand("GETSET", key, value).getBulkReply();
+    }
+
+    public List<String> mget(String... keys) throws JedisException {
+	return sendCommand("MGET", keys).getMultiBulkReply();
+    }
+
+    public int setnx(String key, String value) throws JedisException {
+	return sendCommand("SETNX", key, value).getIntegerReply();
+    }
+
+    public String setex(String key, int seconds, String value)
+	    throws JedisException {
+	return sendCommand("SETEX", key, String.valueOf(seconds), value)
+		.getStatusCodeReply();
+    }
+
+    public String mset(String... keysvalues) throws JedisException {
+	return sendCommand("MSET", keysvalues).getStatusCodeReply();
+    }
+
+    public int msetnx(String... keysvalues) throws JedisException {
+	return sendCommand("MSETNX", keysvalues).getIntegerReply();
+    }
+
+    public int decrBy(String key, int integer) throws JedisException {
+	return sendCommand("DECRBY", key, String.valueOf(integer))
+		.getIntegerReply();
+    }
+
+    public int decr(String key) throws JedisException {
+	return sendCommand("DECR", key).getIntegerReply();
+    }
+
+    public int incrBy(String key, int integer) throws JedisException {
+	return sendCommand("INCRBY", key, String.valueOf(integer))
+		.getIntegerReply();
+    }
+
+    public int incr(String key) throws JedisException {
+	return sendCommand("INCR", key).getIntegerReply();
+    }
+
+    public int append(String key, String value) throws JedisException {
+	return sendCommand("APPEND", key, value).getIntegerReply();
+    }
+
+    public String substr(String key, int start, int end) throws JedisException {
+	return sendCommand("SUBSTR", key, String.valueOf(start),
+		String.valueOf(end)).getBulkReply();
+    }
 }
diff --git a/src/test/java/redis/clients/jedis/tests/commands/AllKindOfValuesCommandsTest.java b/src/test/java/redis/clients/jedis/tests/commands/AllKindOfValuesCommandsTest.java
index 283f776..ede6083 100644
--- a/src/test/java/redis/clients/jedis/tests/commands/AllKindOfValuesCommandsTest.java
+++ b/src/test/java/redis/clients/jedis/tests/commands/AllKindOfValuesCommandsTest.java
@@ -99,7 +99,7 @@ public class AllKindOfValuesCommandsTest extends Assert {
 
     @Test
     public void randomKey() throws JedisException {
-	assertEquals("", jedis.randomKey());
+	assertEquals(null, jedis.randomKey());
 
 	jedis.set("foo", "bar");
 
diff --git a/src/test/java/redis/clients/jedis/tests/commands/StringValuesCommandsTest.java b/src/test/java/redis/clients/jedis/tests/commands/StringValuesCommandsTest.java
index 1ad66fc..c908a03 100644
--- a/src/test/java/redis/clients/jedis/tests/commands/StringValuesCommandsTest.java
+++ b/src/test/java/redis/clients/jedis/tests/commands/StringValuesCommandsTest.java
@@ -1,5 +1,8 @@
 package redis.clients.jedis.tests.commands;
 
+import java.util.ArrayList;
+import java.util.List;
+
 import junit.framework.Assert;
 
 import org.junit.After;
@@ -31,6 +34,158 @@ public class StringValuesCommandsTest extends Assert {
 
 	String value = jedis.get("foo");
 	assertEquals("bar", value);
+
+	assertEquals(null, jedis.get("bar"));
     }
 
-}
+    @Test
+    public void getSet() throws JedisException {
+	String value = jedis.getSet("foo", "bar");
+	assertEquals(null, value);
+	value = jedis.get("foo");
+	assertEquals("bar", value);
+    }
+
+    @Test
+    public void mget() throws JedisException {
+	List<String> values = jedis.mget("foo", "bar");
+	List<String> expected = new ArrayList<String>();
+	expected.add(null);
+	expected.add(null);
+
+	assertEquals(expected, values);
+
+	jedis.set("foo", "bar");
+
+	expected = new ArrayList<String>();
+	expected.add("bar");
+	expected.add(null);
+	values = jedis.mget("foo", "bar");
+
+	assertEquals(expected, values);
+
+	jedis.set("bar", "foo");
+
+	expected = new ArrayList<String>();
+	expected.add("bar");
+	expected.add("foo");
+	values = jedis.mget("foo", "bar");
+
+	assertEquals(expected, values);
+    }
+
+    @Test
+    public void setnx() throws JedisException {
+	int status = jedis.setnx("foo", "bar");
+	assertEquals(1, status);
+	assertEquals("bar", jedis.get("foo"));
+
+	status = jedis.setnx("foo", "bar2");
+	assertEquals(0, status);
+	assertEquals("bar", jedis.get("foo"));
+    }
+
+    @Test
+    public void setex() throws JedisException {
+	String status = jedis.setex("foo", 20, "bar");
+	assertEquals("OK", status);
+	int ttl = jedis.ttl("foo");
+	assertTrue(ttl > 0 && ttl <= 20);
+    }
+
+    @Test
+    public void mset() throws JedisException {
+	String status = jedis.mset("foo", "bar", "bar", "foo");
+	assertEquals("OK", status);
+	assertEquals("bar", jedis.get("foo"));
+	assertEquals("foo", jedis.get("bar"));
+    }
+
+    @Test
+    public void msetnx() throws JedisException {
+	int status = jedis.msetnx("foo", "bar", "bar", "foo");
+	assertEquals(1, status);
+	assertEquals("bar", jedis.get("foo"));
+	assertEquals("foo", jedis.get("bar"));
+
+	status = jedis.msetnx("foo", "bar1", "bar2", "foo2");
+	assertEquals(0, status);
+	assertEquals("bar", jedis.get("foo"));
+	assertEquals("foo", jedis.get("bar"));
+    }
+
+    @Test(expected = JedisException.class)
+    public void incrWrongValue() throws JedisException {
+	jedis.set("foo", "bar");
+	jedis.incr("foo");
+    }
+
+    @Test
+    public void incr() throws JedisException {
+	int value = jedis.incr("foo");
+	assertEquals(1, value);
+	value = jedis.incr("foo");
+	assertEquals(2, value);
+    }
+
+    @Test(expected = JedisException.class)
+    public void incrByWrongValue() throws JedisException {
+	jedis.set("foo", "bar");
+	jedis.incrBy("foo", 2);
+    }
+
+    @Test
+    public void incrBy() throws JedisException {
+	int value = jedis.incrBy("foo", 2);
+	assertEquals(2, value);
+	value = jedis.incrBy("foo", 2);
+	assertEquals(4, value);
+    }
+
+    @Test(expected = JedisException.class)
+    public void decrWrongValue() throws JedisException {
+	jedis.set("foo", "bar");
+	jedis.decr("foo");
+    }
+
+    @Test
+    public void decr() throws JedisException {
+	int value = jedis.decr("foo");
+	assertEquals(-1, value);
+	value = jedis.decr("foo");
+	assertEquals(-2, value);
+    }
+
+    @Test(expected = JedisException.class)
+    public void decrByWrongValue() throws JedisException {
+	jedis.set("foo", "bar");
+	jedis.decrBy("foo", 2);
+    }
+
+    @Test
+    public void decrBy() throws JedisException {
+	int value = jedis.decrBy("foo", 2);
+	assertEquals(-2, value);
+	value = jedis.decrBy("foo", 2);
+	assertEquals(-4, value);
+    }
+
+    @Test
+    public void append() throws JedisException {
+	int value = jedis.append("foo", "bar");
+	assertEquals(3, value);
+	assertEquals("bar", jedis.get("foo"));
+	value = jedis.append("foo", "bar");
+	assertEquals(6, value);
+	assertEquals("barbar", jedis.get("foo"));
+    }
+
+    @Test
+    public void substr() throws JedisException {
+	jedis.set("s", "This is a string");
+	assertEquals("This", jedis.substr("s", 0, 3));
+	assertEquals("ing", jedis.substr("s", -3, -1));
+	assertEquals("This is a string", jedis.substr("s", 0, -1));
+	assertEquals(" string", jedis.substr("s", 9, 100000));
+    }
+}
\ No newline at end of file