diff --git a/IPython/core/history.py b/IPython/core/history.py
index 558e517..e386cf2 100644
--- a/IPython/core/history.py
+++ b/IPython/core/history.py
@@ -307,7 +307,7 @@ class HistoryAccessor(Configurable):
 
     @catch_corrupt_db
     def search(self, pattern="*", raw=True, search_raw=True,
-               output=False, n=None):
+               output=False, n=None, unique=False):
         """Search the database using unix glob-style matching (wildcards
         * and ?).
 
@@ -322,6 +322,8 @@ class HistoryAccessor(Configurable):
         n : None or int
           If an integer is given, it defines the limit of
           returned entries.
+        unique : bool
+          When it is true, return only unique entries.
 
         Returns
         -------
@@ -333,9 +335,13 @@ class HistoryAccessor(Configurable):
         self.writeout_cache()
         sqlform = "WHERE %s GLOB ?" % tosearch
         params = (pattern,)
+        if unique:
+            sqlform += ' GROUP BY {0}'.format(tosearch)
         if n is not None:
             sqlform += " ORDER BY session DESC, line DESC LIMIT ?"
             params += (n,)
+        elif unique:
+            sqlform += " ORDER BY session, line"
         cur = self._run_sql(sqlform, params, raw=raw, output=output)
         if n is not None:
             return reversed(list(cur))
diff --git a/IPython/core/magics/history.py b/IPython/core/magics/history.py
index 3d9884d..63bb4fa 100644
--- a/IPython/core/magics/history.py
+++ b/IPython/core/magics/history.py
@@ -89,6 +89,11 @@ class HistoryMagics(Magics):
         get the last n lines from all sessions. Specify n as a single
         arg, or the default is the last 10 lines.
         """)
+    @argument(
+        '-u', dest='unique', action='store_true',
+        help="""
+        when searching history using `-g`, show only unique history.
+        """)
     @argument('range', nargs='*')
     @skip_doctest
     @line_magic
@@ -165,7 +170,7 @@ class HistoryMagics(Magics):
             else:
                 pattern = "*"
             hist = history_manager.search(pattern, raw=raw, output=get_output,
-                                          n=limit)
+                                          n=limit, unique=args.unique)
             print_nums = True
         elif args.limit is not _unspecified:
             n = 10 if limit is None else limit
diff --git a/IPython/core/tests/test_history.py b/IPython/core/tests/test_history.py
index 5474da9..8797c8b 100644
--- a/IPython/core/tests/test_history.py
+++ b/IPython/core/tests/test_history.py
@@ -61,7 +61,10 @@ def test_history():
 
             # New session
             ip.history_manager.reset()
-            newcmds = ["z=5","class X(object):\n    pass", "k='p'"]
+            newcmds = [u"z=5",
+                       u"class X(object):\n    pass",
+                       u"k='p'",
+                       u"z=5"]
             for i, cmd in enumerate(newcmds, start=1):
                 ip.history_manager.store_inputs(i, cmd)
             gothist = ip.history_manager.get_range(start=1, stop=4)
@@ -70,35 +73,53 @@ def test_history():
             gothist = ip.history_manager.get_range(-1, 1, 4)
             nt.assert_equal(list(gothist), zip([1,1,1],[1,2,3], hist))
 
+            newhist = [(2, i, c) for (i, c) in enumerate(newcmds, 1)]
+
             # Check get_hist_tail
-            gothist = ip.history_manager.get_tail(4, output=True,
+            gothist = ip.history_manager.get_tail(5, output=True,
                                                     include_latest=True)
-            expected = [(1, 3, (hist[-1], "spam")),
-                        (2, 1, (newcmds[0], None)),
-                        (2, 2, (newcmds[1], None)),
-                        (2, 3, (newcmds[2], None)),]
+            expected = [(1, 3, (hist[-1], "spam"))] \
+                + [(s, n, (c, None)) for (s, n, c) in newhist]
             nt.assert_equal(list(gothist), expected)
 
             gothist = ip.history_manager.get_tail(2)
-            expected = [(2, 1, newcmds[0]),
-                        (2, 2, newcmds[1])]
+            expected = newhist[-3:-1]
             nt.assert_equal(list(gothist), expected)
 
             # Check get_hist_search
             gothist = ip.history_manager.search("*test*")
             nt.assert_equal(list(gothist), [(1,2,hist[1])] )
+
             gothist = ip.history_manager.search("*=*")
             nt.assert_equal(list(gothist),
                             [(1, 1, hist[0]),
                              (1, 2, hist[1]),
                              (1, 3, hist[2]),
-                             (2, 1, newcmds[0]),
-                             (2, 3, newcmds[2])])
-            gothist = ip.history_manager.search("*=*", n=3)
+                             newhist[0],
+                             newhist[2],
+                             newhist[3]])
+
+            gothist = ip.history_manager.search("*=*", n=4)
+            nt.assert_equal(list(gothist),
+                            [(1, 3, hist[2]),
+                             newhist[0],
+                             newhist[2],
+                             newhist[3]])
+
+            gothist = ip.history_manager.search("*=*", unique=True)
+            nt.assert_equal(list(gothist),
+                            [(1, 1, hist[0]),
+                             (1, 2, hist[1]),
+                             (1, 3, hist[2]),
+                             newhist[2],
+                             newhist[3]])
+
+            gothist = ip.history_manager.search("*=*", unique=True, n=3)
             nt.assert_equal(list(gothist),
                             [(1, 3, hist[2]),
-                             (2, 1, newcmds[0]),
-                             (2, 3, newcmds[2])])
+                             newhist[2],
+                             newhist[3]])
+
             gothist = ip.history_manager.search("b*", output=True)
             nt.assert_equal(list(gothist), [(1,3,(hist[2],"spam"))] )