diff --git a/CHANGES.txt b/CHANGES.txt
index df8dedf1ddb..b93fec1db5a 100644
--- a/CHANGES.txt
+++ b/CHANGES.txt
@@ -739,6 +739,8 @@ Release 0.92.0 - Unreleased
    HBASE-3939  Some crossports of Hadoop IPC fixes
    HBASE-4756  Enable tab-completion in HBase shell (Ryan Thiessen)
    HBASE-4759  Migrate from JUnit 4.8.2 to JUnit 4.10 (nkeywal)
+   HBASE-4554  Allow set/unset coprocessor table attributes from shell
+               (Mingjie Lai)
 
   TASKS
    HBASE-3559  Move report of split to master OFF the heartbeat channel
diff --git a/src/main/java/org/apache/hadoop/hbase/HConstants.java b/src/main/java/org/apache/hadoop/hbase/HConstants.java
index a468100a941..d22f50a42bd 100644
--- a/src/main/java/org/apache/hadoop/hbase/HConstants.java
+++ b/src/main/java/org/apache/hadoop/hbase/HConstants.java
@@ -537,9 +537,9 @@ public final class HConstants {
           Bytes.toString(ROOT_TABLE_NAME), SPLIT_LOGDIR_NAME }));
 
   public static final Pattern CP_HTD_ATTR_KEY_PATTERN = Pattern.compile
-      ("coprocessor\\$([0-9]+)", Pattern.CASE_INSENSITIVE);
+      ("^coprocessor\\$([0-9]+)$", Pattern.CASE_INSENSITIVE);
   public static final Pattern CP_HTD_ATTR_VALUE_PATTERN =
-      Pattern.compile("([^\\|]*)\\|([^\\|]+)\\|[\\s]*([\\d]*)[\\s]*(\\|.*)?");
+      Pattern.compile("(^[^\\|]*)\\|([^\\|]+)\\|[\\s]*([\\d]*)[\\s]*(\\|.*)?$");
 
   public static final String CP_HTD_ATTR_VALUE_PARAM_KEY_PATTERN = "[^=,]+";
   public static final String CP_HTD_ATTR_VALUE_PARAM_VALUE_PATTERN = "[^,]+";
diff --git a/src/main/ruby/hbase/admin.rb b/src/main/ruby/hbase/admin.rb
index 61e04d81885..17cc891ab4c 100644
--- a/src/main/ruby/hbase/admin.rb
+++ b/src/main/ruby/hbase/admin.rb
@@ -364,6 +364,37 @@ module Hbase
           htd.setReadOnly(JBoolean.valueOf(arg[READONLY])) if arg[READONLY]
           htd.setMemStoreFlushSize(JLong.valueOf(arg[MEMSTORE_FLUSHSIZE])) if arg[MEMSTORE_FLUSHSIZE]
           htd.setDeferredLogFlush(JBoolean.valueOf(arg[DEFERRED_LOG_FLUSH])) if arg[DEFERRED_LOG_FLUSH]
+
+          # set a coprocessor attribute
+          if arg.kind_of?(Hash)
+            arg.each do |key, value|
+              k = String.new(key) # prepare to strip
+              k.strip!
+
+              if (k =~ /coprocessor/i)
+                # validate coprocessor specs
+                v = String.new(value)
+                v.strip!
+                if !(v =~ /^([^\|]*)\|([^\|]+)\|[\s]*([\d]*)[\s]*(\|.*)?$/)
+                  raise ArgumentError, "Coprocessor value doesn't match spec: #{v}"
+                end
+
+                # generate a coprocessor ordinal by checking max id of existing cps
+                maxId = 0
+                htd.getValues().each do |k1, v1|
+                  attrName = org.apache.hadoop.hbase.util.Bytes.toString(k1.get())
+                  # a cp key is coprocessor$(\d)
+                  if (attrName =~ /coprocessor\$(\d+)/i)
+                    ids = attrName.scan(/coprocessor\$(\d+)/i)
+                    maxId = ids[0][0].to_i if ids[0][0].to_i > maxId
+                  end
+                end
+                maxId += 1
+                htd.setValue(k + "\$" + maxId.to_s, value)
+              end
+            end
+          end
+
           @admin.modifyTable(table_name.to_java_bytes, htd)
           if wait == true
             puts "Updating all regions with the new schema..."
@@ -372,6 +403,25 @@ module Hbase
           next
         end
 
+        # Unset table attributes
+        if method == "table_att_unset"
+          if arg.kind_of?(Hash)
+            if (!arg[NAME])
+              next
+            end
+            if (htd.getValue(arg[NAME]) == nil)
+              raise ArgumentError, "Can not find attribute: #{arg[NAME]}"
+            end
+            htd.remove(arg[NAME].to_java_bytes)
+            @admin.modifyTable(table_name.to_java_bytes, htd)
+            if wait == true
+              puts "Updating all regions with the new schema..."
+              alter_status(table_name)
+            end
+          end
+          next
+        end
+
         # Unknown method
         raise ArgumentError, "Unknown method: #{method}"
       end
diff --git a/src/main/ruby/shell/commands/alter.rb b/src/main/ruby/shell/commands/alter.rb
index ee3668db296..33fbcb3cdd6 100644
--- a/src/main/ruby/shell/commands/alter.rb
+++ b/src/main/ruby/shell/commands/alter.rb
@@ -48,6 +48,26 @@ For example, to change the max size of a family to 128MB, do:
 
   hbase> alter 't1', METHOD => 'table_att', MAX_FILESIZE => '134217728'
 
+You can add a table coprocessor by setting a table coprocessor attribute:
+
+  hbase> alter 't1', METHOD => 'table_att',
+    'coprocessor'=>'hdfs:///foo.jar|com.foo.FooRegionObserver|1001|arg1=1,arg2=2'
+
+Since you can have multiple coprocessors configured for a table, a
+sequence number will be automatically appended to the attribute name
+to uniquely identify it.
+
+The coprocessor attribute must match the pattern below in order for
+the framework to understand how to load the coprocessor classes:
+
+  [coprocessor jar file location] | class name | [priority] | [arguments]
+
+You can also remove a table-scope attribute:
+
+  hbase> alter 't1', METHOD => 'table_att_unset', NAME => 'MAX_FILESIZE'
+
+  hbase> alter 't1', METHOD => 'table_att_unset', NAME => 'coprocessor$1'
+
 There could be more than one alteration in one command:
 
   hbase> alter 't1', {NAME => 'f1'}, {NAME => 'f2', METHOD => 'delete'}
diff --git a/src/test/ruby/hbase/admin_test.rb b/src/test/ruby/hbase/admin_test.rb
index df88100eee9..0c2672b89f5 100644
--- a/src/test/ruby/hbase/admin_test.rb
+++ b/src/test/ruby/hbase/admin_test.rb
@@ -271,5 +271,44 @@ module Hbase
       admin.alter(@test_name, true, METHOD => 'table_att', 'MAX_FILESIZE' => 12345678)
       assert_match(/12345678/, admin.describe(@test_name))
     end
+
+    define_test "alter should be able to change coprocessor attributes" do
+      drop_test_table(@test_name)
+      create_test_table(@test_name)
+
+      cp_key = "coprocessor"
+      class_name = "SimpleRegionObserver"
+
+      cp_value = "hdfs:///foo.jar|" + class_name + "|12|arg1=1,arg2=2"
+
+      # eval() is used to convert a string to regex
+      assert_no_match(eval("/" + class_name + "/"), admin.describe(@test_name))
+      assert_no_match(eval("/" + cp_key + "/"), admin.describe(@test_name))
+      admin.alter(@test_name, true, 'METHOD' => 'table_att', cp_key => cp_value)
+      assert_match(eval("/" + class_name + "/"), admin.describe(@test_name))
+      assert_match(eval("/" + cp_key + "\\$(\\d+)/"), admin.describe(@test_name))
+    end
+
+    define_test "alter should be able to remove a table attribute" do
+      drop_test_table(@test_name)
+      create_test_table(@test_name)
+
+      key1 = "coprocessor"
+      key2 = "MAX_FILESIZE"
+      admin.alter(@test_name, true, 'METHOD' => 'table_att', key1 => "|TestCP||")
+      admin.alter(@test_name, true, 'METHOD' => 'table_att', key2 => 12345678)
+
+      # eval() is used to convert a string to regex
+      assert_match(eval("/" + key1 + "\\$(\\d+)/"), admin.describe(@test_name))
+      assert_match(eval("/" + key2 + "/"), admin.describe(@test_name))
+
+      # get the cp key
+      cp_keys = admin.describe(@test_name).scan(/(coprocessor\$\d+)/i)
+
+      admin.alter(@test_name, true, 'METHOD' => 'table_att_unset', 'NAME' => cp_keys[0][0])
+      admin.alter(@test_name, true, 'METHOD' => 'table_att_unset', 'NAME' => key2)
+      assert_no_match(eval("/" + key1 + "\\$(\\d+)/"), admin.describe(@test_name))
+      assert_no_match(eval("/" + key2 + "/"), admin.describe(@test_name))
+    end
   end
 end