diff --git a/lib/irb/ext/multi-irb.rb b/lib/irb/ext/multi-irb.rb
index d697b1ecbe..cd1ddd9f9f 100644
--- a/lib/irb/ext/multi-irb.rb
+++ b/lib/irb/ext/multi-irb.rb
@@ -84,9 +84,9 @@ module IRB
     # See Thread#exit for more information.
     def kill(*keys)
       for key in keys
-	th, _ = search(key)
-	IRB.fail IrbAlreadyDead unless th.alive?
-	th.exit
+        th, _ = search(key)
+        IRB.fail IrbAlreadyDead unless th.alive?
+        th.exit
       end
     end
 
@@ -106,15 +106,15 @@ module IRB
     # Raises a NoSuchJob exception if no job can be found with the given +key+.
     def search(key)
       job = case key
-      when Integer
-	@jobs[key]
-      when Irb
-	@jobs.find{|k, v| v.equal?(key)}
-      when Thread
-	@jobs.assoc(key)
-      else
-	@jobs.find{|k, v| v.context.main.equal?(key)}
-      end
+            when Integer
+              @jobs[key]
+            when Irb
+              @jobs.find{|k, v| v.equal?(key)}
+            when Thread
+              @jobs.assoc(key)
+            else
+              @jobs.find{|k, v| v.context.main.equal?(key)}
+            end
       IRB.fail NoSuchJob, key if job.nil?
       job
     end
@@ -123,21 +123,21 @@ module IRB
     def delete(key)
       case key
       when Integer
-	IRB.fail NoSuchJob, key unless @jobs[key]
-	@jobs[key] = nil
+        IRB.fail NoSuchJob, key unless @jobs[key]
+        @jobs[key] = nil
       else
-	catch(:EXISTS) do
-	  @jobs.each_index do
-	    |i|
-	    if @jobs[i] and (@jobs[i][0] == key ||
-			     @jobs[i][1] == key ||
-			     @jobs[i][1].context.main.equal?(key))
-	      @jobs[i] = nil
-	      throw :EXISTS
-	    end
-	  end
-	  IRB.fail NoSuchJob, key
-	end
+        catch(:EXISTS) do
+          @jobs.each_index do
+            |i|
+            if @jobs[i] and (@jobs[i][0] == key ||
+                @jobs[i][1] == key ||
+                @jobs[i][1].context.main.equal?(key))
+              @jobs[i] = nil
+              throw :EXISTS
+            end
+          end
+          IRB.fail NoSuchJob, key
+        end
       end
       until assoc = @jobs.pop; end unless @jobs.empty?
       @jobs.push assoc
@@ -147,25 +147,25 @@ module IRB
     def inspect
       ary = []
       @jobs.each_index do
-	|i|
-	th, irb = @jobs[i]
-	next if th.nil?
+        |i|
+        th, irb = @jobs[i]
+        next if th.nil?
 
-	if th.alive?
-	  if th.stop?
-	    t_status = "stop"
-	  else
-	    t_status = "running"
-	  end
-	else
-	  t_status = "exited"
-	end
-	ary.push format("#%d->%s on %s (%s: %s)",
-			i,
-			irb.context.irb_name,
-			irb.context.main,
-			th,
-			t_status)
+        if th.alive?
+          if th.stop?
+            t_status = "stop"
+          else
+            t_status = "running"
+          end
+        else
+          t_status = "exited"
+        end
+        ary.push format("#%d->%s on %s (%s: %s)",
+          i,
+          irb.context.irb_name,
+          irb.context.main,
+          th,
+          t_status)
       end
       ary.join("\n")
     end
@@ -192,39 +192,39 @@ module IRB
     parent_thread = Thread.current
     Thread.start do
       begin
-	irb = Irb.new(workspace, file)
+        irb = Irb.new(workspace, file)
       rescue
-	print "Subirb can't start with context(self): ", workspace.main.inspect, "\n"
-	print "return to main irb\n"
-	Thread.pass
-	Thread.main.wakeup
-	Thread.exit
+        print "Subirb can't start with context(self): ", workspace.main.inspect, "\n"
+        print "return to main irb\n"
+        Thread.pass
+        Thread.main.wakeup
+        Thread.exit
       end
       @CONF[:IRB_RC].call(irb.context) if @CONF[:IRB_RC]
       @JobManager.insert(irb)
       @JobManager.current_job = irb
       begin
-	system_exit = false
-	catch(:IRB_EXIT) do
-	  irb.eval_input
-	end
+        system_exit = false
+        catch(:IRB_EXIT) do
+          irb.eval_input
+        end
       rescue SystemExit
-	system_exit = true
-	raise
-	#fail
+        system_exit = true
+        raise
+        #fail
       ensure
-	unless system_exit
-	  @JobManager.delete(irb)
-	  if @JobManager.current_job == irb
-	    if parent_thread.alive?
-	      @JobManager.current_job = @JobManager.irb(parent_thread)
-	      parent_thread.run
-	    else
-	      @JobManager.current_job = @JobManager.main_irb
-	      @JobManager.main_thread.run
-	    end
-	  end
-	end
+        unless system_exit
+          @JobManager.delete(irb)
+          if @JobManager.current_job == irb
+            if parent_thread.alive?
+              @JobManager.current_job = @JobManager.irb(parent_thread)
+              parent_thread.run
+            else
+              @JobManager.current_job = @JobManager.main_irb
+              @JobManager.main_thread.run
+            end
+          end
+        end
       end
     end
     Thread.stop
diff --git a/lib/irb/output-method.rb b/lib/irb/output-method.rb
index aae9e2294d..e0ba25f3e4 100644
--- a/lib/irb/output-method.rb
+++ b/lib/irb/output-method.rb
@@ -35,7 +35,7 @@ module IRB
     # #parse_printf_format
     def printf(format, *opts)
       if /(%*)%I/ =~ format
-	format, opts = parse_printf_format(format, opts)
+        format, opts = parse_printf_format(format, opts)
       end
       print sprintf(format, *opts)
     end
@@ -58,8 +58,8 @@ module IRB
     # character.
     def puts(*objs)
       for obj in objs
-	print(*obj)
-	print "\n"
+        print(*obj)
+        print "\n"
       end
     end