diff --git a/IPython/Extensions/clearcmd.py b/IPython/Extensions/clearcmd.py
new file mode 100644
index 0000000..3714e8f
--- /dev/null
+++ b/IPython/Extensions/clearcmd.py
@@ -0,0 +1,38 @@
+# -*- coding: utf-8 -*-
+""" IPython extension: add %clear magic """
+
+import IPython.ipapi
+ip = IPython.ipapi.get()
+
+def clear_list(l):
+    while l:
+        l.pop()
+
+def clear_f(self,arg):
+    """ Clear various data (e.g. stored history data)
+    
+    %clear out - clear output history
+    %clear in  - clear input history
+    """
+    
+    api = self.getapi()
+    for target in arg.split():
+        if target == 'out':
+            print "Flushing output cache (%d entries)" % len(api.user_ns()['_oh'])
+            self.outputcache.flush()
+        elif target == 'in':
+            print "Flushing input history"
+            from IPython import iplib
+            clear_list(self.input_hist)
+            clear_list(self.input_hist_raw)
+            for n in range(1,self.outputcache.prompt_count + 1):
+                key = '_i'+`n`
+                try:
+                    del self.user_ns[key]
+                except: pass
+
+ip.expose_magic("clear",clear_f)
+    
+
+
+
diff --git a/IPython/Extensions/ipy_system_conf.py b/IPython/Extensions/ipy_system_conf.py
index aabbd56..1f4ae90 100644
--- a/IPython/Extensions/ipy_system_conf.py
+++ b/IPython/Extensions/ipy_system_conf.py
@@ -18,7 +18,7 @@ import sys
 import ext_rehashdir # %rehashdir magic
 import ext_rescapture # var = !ls and var = %magic
 import pspersistence # %store magic
-
+import clearcmd # %clear
 # Basic readline config
 
 o = ip.options()
\ No newline at end of file
diff --git a/IPython/Prompts.py b/IPython/Prompts.py
index 127d8d0..891f578 100644
--- a/IPython/Prompts.py
+++ b/IPython/Prompts.py
@@ -2,7 +2,7 @@
 """
 Classes for handling input/output prompts.
 
-$Id: Prompts.py 1076 2006-01-24 17:27:05Z vivainio $"""
+$Id: Prompts.py 1261 2006-04-11 14:37:02Z vivainio $"""
 
 #*****************************************************************************
 #       Copyright (C) 2001-2006 Fernando Perez <fperez@colorado.edu>
@@ -439,7 +439,6 @@ class CachedOutput:
         # other more normal stuff
         # b/c each call to the In[] prompt raises it by 1, even the first.
         self.prompt_count = 0
-        self.cache_count = 1
         # Store the last prompt string each time, we need it for aligning
         # continuation and auto-rewrite prompts
         self.last_prompt = ''
@@ -545,7 +544,13 @@ class CachedOutput:
 
     def update(self,arg):
         #print '***cache_count', self.cache_count # dbg
-        if self.cache_count >= self.cache_size and self.do_full_cache:
+        if len(self.user_ns['_oh']) >= self.cache_size and self.do_full_cache:
+            warn('Output cache limit (currently '+\
+                  `self.cache_count`+' entries) hit.\n'
+                 'Flushing cache and resetting history counter...\n'
+                 'The only history variables available will be _,__,___ and _1\n'
+                 'with the current result.')
+
             self.flush()
         # Don't overwrite '_' and friends if '_' is in __builtin__ (otherwise
         # we cause buggy behavior for things like gettext).
@@ -558,7 +563,6 @@ class CachedOutput:
         # hackish access to top-level  namespace to create _1,_2... dynamically
         to_main = {}
         if self.do_full_cache:
-            self.cache_count += 1
             self.entries.append(arg)
             new_result = '_'+`self.prompt_count`
             to_main[new_result] = self.entries[-1]
@@ -569,16 +573,16 @@ class CachedOutput:
         if not self.do_full_cache:
             raise ValueError,"You shouldn't have reached the cache flush "\
                   "if full caching is not enabled!"
-        warn('Output cache limit (currently '+\
-              `self.cache_count`+' entries) hit.\n'
-             'Flushing cache and resetting history counter...\n'
-             'The only history variables available will be _,__,___ and _1\n'
-             'with the current result.')
         # delete auto-generated vars from global namespace
+        
         for n in range(1,self.prompt_count + 1):
             key = '_'+`n`
             try:
                 del self.user_ns[key]
             except: pass
-        self.prompt_count = 1
-        self.cache_count = 1
+        self.user_ns['_oh'].clear()
+        
+        if '_' not in __builtin__.__dict__:
+            self.user_ns.update({'_':None,'__':None, '___':None})
+        import gc
+        gc.collect() # xxx needed?
diff --git a/doc/ChangeLog b/doc/ChangeLog
index 9cbc75b..8f3929a 100644
--- a/doc/ChangeLog
+++ b/doc/ChangeLog
@@ -3,6 +3,11 @@
 	* iplib.py, ipmaker.py: .ipy extension now means "ipython batch file"
 	in command line. E.g. "ipython test.ipy" runs test.ipy with ipython
 	prefilters, allowing stuff like magics and aliases in the file.
+	
+	* Prompts.py, Extensions/clearcmd.py, ipy_system_conf.py: %clear magic 
+	added. Supported now are "%clear in" and "%clear out" (clear input and 
+	output history, respectively). Also fixed CachedOutput.flush to 
+	properly flush the output cache.
 
 2006-03-28  Ville Vainio  <vivainio@gmail.com>