diff --git a/PKG-INFO b/PKG-INFO
index 684b6f9..453420f 100644
--- a/PKG-INFO
+++ b/PKG-INFO
@@ -31,9 +31,9 @@ pythonbrew command [options]
 Install some Pythons::
 
   pythonbrew install 2.6.6
-  pythonbrew install Python-2.5.5
-  pythonbrew install --configure="CC=gcc_4.1" Python-2.6.6
-  pythonbrew install --no-setuptools Python-2.6.6
+  pythonbrew install --force 2.5.5
+  pythonbrew install --configure="CC=gcc_4.1" 2.6.6
+  pythonbrew install --no-setuptools 2.6.6
   pythonbrew install http://www.python.org/ftp/python/2.7/Python-2.7.tgz
   
 Switch python in the $PATH::
@@ -41,10 +41,17 @@ Switch python in the $PATH::
   pythonbrew switch 2.6.6
   pythonbrew switch Python-2.5.5
 
+Using python in the PATH::
+
+  pythonbrew use 2.6.6
+
+List the installed versions of Python::
+
+  pythonbrew list
+
 List the available install versions of Python::
 
-  pythonbrew list 2.6
-  pythonbrew list 3.0
+  pythonbrew list -k
 
 Uninstall some Pythons::
 
@@ -80,12 +87,18 @@ installed
   List the installed versions of python.
 
 switch <version>
-  Switch to the given version.
+  Switch to the given version of python.
 
-list <version>
+use <version>
+  Using the given version of python.
+
+list
+  List the installed versions of Python.
+  
+list -k <version>
   List the available install version of python.
   
-uninstall Python-<version>
+uninstall <version>
   Uninstall the given version of python.
 
 clean
diff --git a/README.rst b/README.rst
index 7c099aa..04c1b7d 100644
--- a/README.rst
+++ b/README.rst
@@ -30,20 +30,27 @@ pythonbrew command [options]
 Install some Pythons::
 
   pythonbrew install 2.6.6
-  pythonbrew install Python-2.5.5
-  pythonbrew install --configure="CC=gcc_4.1" Python-2.6.6
-  pythonbrew install --no-setuptools Python-2.6.6
+  pythonbrew install --force 2.5.5
+  pythonbrew install --configure="CC=gcc_4.1" 2.6.6
+  pythonbrew install --no-setuptools 2.6.6
   pythonbrew install http://www.python.org/ftp/python/2.7/Python-2.7.tgz
   
 Switch python in the $PATH::
 
   pythonbrew switch 2.6.6
-  pythonbrew switch Python-2.5.5
+  pythonbrew switch 2.5.5
+
+Using python in the PATH::
+
+  pythonbrew use 2.6.6
+
+List the installed versions of Python::
+
+  pythonbrew list
 
 List the available install versions of Python::
 
-  pythonbrew list 2.6
-  pythonbrew list 3.0
+  pythonbrew list -k
 
 Uninstall some Pythons::
 
@@ -79,12 +86,18 @@ installed
   List the installed versions of python.
 
 switch <version>
-  Switch to the given version.
+  Switch to the given version of python.
 
-list <version>
+use <version>
+  Using the given version of python.
+
+list
+  List the installed versions of Python.
+  
+list -k <version>
   List the available install version of python.
   
-uninstall Python-<version>
+uninstall <version>
   Uninstall the given version of python.
 
 clean
diff --git a/pythonbrew-install b/pythonbrew-install
index b138d0c..a761572 100755
--- a/pythonbrew-install
+++ b/pythonbrew-install
@@ -1,6 +1,6 @@
 #!/usr/bin/env bash
 
-PYTHON=`command -v python`
+PYTHONS="/usr/bin/python /usr/bin/python2 `command -v python`"
 CURL=`command -v curl`
 
 usage()
@@ -22,7 +22,7 @@ parse_arguments()
     for arg do
         val=`echo "$arg" | sed -e "s;--[^=]*=;;"`
         case "$arg" in
-            --python=*) PYTHON="$val" ;;
+            --python=*) PYTHONS="$val $PYTHONS" ;;
             --help) usage ;;
             *) echo "Can't find the option. :$arg";;
         esac
@@ -31,22 +31,28 @@ parse_arguments()
 
 parse_arguments $@
 
-if [[ ! -x $PYTHON ]] ; then
-    echo "pythonbrew required Python (2.4, 2.5 or 2.6)."
-    exit
-fi
 if [[ ! -x $CURL ]] ; then
     echo "pythonbrew required curl. curl was not found in your path."
+    exit
 fi
 
-PYTHON_VERSION=`$PYTHON -V 2>&1`
-PYTHON_VERSION=${PYTHON_VERSION/"Python "/""}
-PYTHON_VERSION_S=`echo $PYTHON_VERSION | sed -e "s/\(^[[:digit:]]\{1,\}.[[:digit:]]\{1,\}\).*/\1/"`
-
-if [[ $PYTHON_VERSION_S != "2.4" ]] && [[ $PYTHON_VERSION_S != "2.5" ]] && [[ $PYTHON_VERSION_S != "2.6" ]] ; then
-    printf "Python's version is $PYTHON_VERSION_S:
-  2.4 <= python < 3.0 is required.
-"
+for PYTHON in $PYTHONS ; do
+	if [[ ! -x $PYTHON ]] ; then
+	    continue
+	fi
+	
+	PYTHON_VERSION=`$PYTHON -V 2>&1`
+	PYTHON_VERSION=${PYTHON_VERSION/"Python "/""}
+	PYTHON_VERSION_S=`echo $PYTHON_VERSION | sed -e "s/\(^[[:digit:]]\{1,\}.[[:digit:]]\{1,\}\).*/\1/"`
+	
+	if [[ $PYTHON_VERSION_S = "2.4" ]] || [[ $PYTHON_VERSION_S = "2.5" ]] || [[ $PYTHON_VERSION_S = "2.6" ]] ; then
+		PYTHON_FOUND='1'
+		break
+	fi
+done
+if [[ $PYTHON_FOUND != '1' ]] ; then
+    echo "pythonbrew required Python (2.4, 2.5 or 2.6)."
+    #TODO Installing python.
     exit
 fi
 
diff --git a/pythonbrew/commands/clean.py b/pythonbrew/commands/clean.py
index 76c3ce7..99aed07 100644
--- a/pythonbrew/commands/clean.py
+++ b/pythonbrew/commands/clean.py
@@ -14,6 +14,6 @@ class CleanCommand(Command):
         
     def _clean(self, root):
         for dir in os.listdir(root):
-            rm_r("%s/%s" % (root, dir))
+            rm_r(os.path.join(root, dir))
 
 CleanCommand()
diff --git a/pythonbrew/commands/installed.py b/pythonbrew/commands/installed.py
index b8ba035..2524f13 100644
--- a/pythonbrew/commands/installed.py
+++ b/pythonbrew/commands/installed.py
@@ -1,9 +1,9 @@
 import os
-import sys
 from subprocess import Popen, PIPE
 from pythonbrew.basecommand import Command
 from pythonbrew.define import PATH_PYTHONS
 from pythonbrew.log import logger
+from pythonbrew.util import get_current_python_path
 
 class InstalledCommand(Command):
     name = "installed"
@@ -11,20 +11,14 @@ class InstalledCommand(Command):
     summary = "List the installed versions of python"
     
     def run_command(self, options, args):
-        cur = None
-        if not os.path.islink("%s/current" % PATH_PYTHONS):
-            p = Popen('command -v python', stdout=PIPE, shell=True)
-            p.wait()
-            if p.returncode == 0:
-                logger.info("%s (*)" % p.stdout.read().strip())
-        elif os.path.islink("%s/current" % PATH_PYTHONS):
-            cur = os.path.basename(os.path.realpath("%s/current" % PATH_PYTHONS))
-        for d in sorted(os.listdir("%s/" % PATH_PYTHONS)):
-            if d == "current":
-                continue
-            if cur == d:
-                logger.info("%s (*)" % cur)
+        cur = get_current_python_path()
+        for d in sorted(os.listdir('%s/' % PATH_PYTHONS)):
+            if cur == os.path.join(PATH_PYTHONS, d, 'bin','python'):
+                logger.info('%s (*)' % d)
+                cur = None
             else:
-                logger.info("%s" % (d))
-
+                logger.info(d)
+        if cur:
+            logger.info('%s (*)' % cur)
+        
 InstalledCommand()
diff --git a/pythonbrew/commands/list.py b/pythonbrew/commands/list.py
index 42b4153..3952ec5 100644
--- a/pythonbrew/commands/list.py
+++ b/pythonbrew/commands/list.py
@@ -1,25 +1,53 @@
+import os
 import re
 from pythonbrew.basecommand import Command
-from pythonbrew.define import PYTHON_VERSION_URL, LATEST_VERSIONS_OF_PYTHON
-from pythonbrew.util import Package
+from pythonbrew.define import PYTHON_VERSION_URL, LATEST_VERSIONS_OF_PYTHON,\
+    PATH_PYTHONS
+from pythonbrew.util import Package, get_current_python_path
 from pythonbrew.log import logger
 
 class ListCommand(Command):
     name = "list"
     usage = "%prog [VERSION]"
-    summary = "List the available install version of python"
-
+    summary = "List the installed versions of Python"
+    
     def __init__(self):
         super(ListCommand, self).__init__()
         self.parser.add_option(
-            "--all-versions",
-            dest="all_versions",
-            action="store_true",
+            '-a', '--all-versions',
+            dest='all_versions',
+            action='store_true',
             default=False,
-            help="All versions of Python are visible."
+            help='All versions of Python are visible'
+        )
+        self.parser.add_option(
+            '-k', '--known',
+            dest='known',
+            action='store_true',
+            default=False,
+            help='List the available install versions of Python'
         )
     
     def run_command(self, options, args):
+        if options.known:
+            self.available_install(options, args)
+        else:
+            self.installed(options, args)
+    
+    def installed(self, options, args):
+        logger.info('# installed pythons')
+        cur = get_current_python_path()
+        for d in sorted(os.listdir('%s/' % PATH_PYTHONS)):
+            if cur == os.path.join(PATH_PYTHONS, d, 'bin','python'):
+                logger.info('%s (*)' % d)
+                cur = None
+            else:
+                logger.info('%s' % d)
+        if cur:
+            logger.info('%s (*)' % cur)
+    
+    def available_install(self, options, args):
+        logger.info('# available install pythons')
         if args:
             pkg = Package(args[0])
             _re = re.compile(r"%s" % pkg.name)
@@ -31,7 +59,7 @@ class ListCommand(Command):
                 for pkgname in pkgs:
                     logger.info("%s" % pkgname)
             else:
-                print "Python version not found. `%s`" % pkg.name
+                logger.info("Python version not found. `%s`" % pkg.name)
         else:
             for pkgname in self._get_packages_name(options):
                 logger.info("%s" % pkgname)
diff --git a/pythonbrew/commands/switch.py b/pythonbrew/commands/switch.py
index c5630bf..b4fc0b9 100644
--- a/pythonbrew/commands/switch.py
+++ b/pythonbrew/commands/switch.py
@@ -2,13 +2,13 @@ import os
 import sys
 from pythonbrew.basecommand import Command
 from pythonbrew.define import PATH_PYTHONS, PATH_BIN
-from pythonbrew.util import off, symlink, Package
+from pythonbrew.util import Package, write_current
 from pythonbrew.log import logger
 
 class SwitchCommand(Command):
     name = "switch"
     usage = "%prog VERSION"
-    summary = "Switch to the given version"
+    summary = "Switch to the given version of python"
     
     def run_command(self, options, args):
         if not args:
@@ -20,19 +20,10 @@ class SwitchCommand(Command):
         if not os.path.isdir(pkgdir):
             logger.info("`%s` is not installed." % pkgname)
             sys.exit(1)
-        self._switch_dir(pkgdir)
-        logger.info("Switched to %s" % pkgname)
-    
-    def _switch_dir(self, pkgdir):
-        off()
-        symlink(pkgdir, "%s/current" % PATH_PYTHONS)
+        pkgbin = os.path.join(pkgdir,'bin')
         
-        # I want better code...
-        current_bin = os.path.join(PATH_PYTHONS,'current','bin')
-        if not os.path.isfile(os.path.join(current_bin,"python")):
-            if os.path.isfile(os.path.join(current_bin,"python3")):
-                symlink(os.path.realpath("%s/python3" % current_bin), os.path.join(PATH_BIN,"python"))
-            elif os.path.isfile(os.path.join(current_bin,"python3.0")):
-                symlink(os.path.realpath("%s/python3.0" % current_bin), os.path.join(PATH_BIN,"python"))
+        write_current('%s:%s' % (PATH_BIN, pkgbin))
+        
+        logger.info("Switched to %s" % pkgname)
 
 SwitchCommand()
diff --git a/pythonbrew/commands/uninstall.py b/pythonbrew/commands/uninstall.py
index 35bcc74..90a3562 100644
--- a/pythonbrew/commands/uninstall.py
+++ b/pythonbrew/commands/uninstall.py
@@ -2,7 +2,7 @@ import os
 import sys
 from pythonbrew.basecommand import Command
 from pythonbrew.define import PATH_PYTHONS
-from pythonbrew.util import off, rm_r, Package
+from pythonbrew.util import off, rm_r, Package, get_current_python_path
 from pythonbrew.log import logger
 
 class UninstallCommand(Command):
@@ -14,14 +14,12 @@ class UninstallCommand(Command):
         if args:
             pkg = Package(args[0])
             pkgname = pkg.name
-            pkgpath = "%s/%s" % (PATH_PYTHONS, pkgname)
+            pkgpath = os.path.join(PATH_PYTHONS, pkgname)
             if not os.path.isdir(pkgpath):
                 logger.info("`%s` is not installed." % pkgname)
                 sys.exit(1)
-            if os.path.islink("%s/current" % PATH_PYTHONS):
-                curpath = os.path.realpath("%s/current" % PATH_PYTHONS)
-                if pkgpath == curpath:
-                    off()
+            if get_current_python_path() == os.path.join(pkgpath,'bin','python'):
+                off()
             rm_r(pkgpath)
         else:
             self.parser.print_help()
diff --git a/pythonbrew/commands/update.py b/pythonbrew/commands/update.py
index 1e455c0..b17eb00 100644
--- a/pythonbrew/commands/update.py
+++ b/pythonbrew/commands/update.py
@@ -55,7 +55,6 @@ class UpdateCommand(Command):
             s.check_call('%s %s/pythonbrew_install.py --upgrade' % (sys.executable, extract_dir))
         except:
             logger.error("Failed to update pythonbrew.")
-            raise
             sys.exit(1)
         logger.info("The pythonbrew has been updated.")
 
diff --git a/pythonbrew/commands/use.py b/pythonbrew/commands/use.py
new file mode 100644
index 0000000..36268b9
--- /dev/null
+++ b/pythonbrew/commands/use.py
@@ -0,0 +1,29 @@
+import os
+import sys
+from pythonbrew.basecommand import Command
+from pythonbrew.define import PATH_PYTHONS, PATH_BIN
+from pythonbrew.util import Package, write_temp
+from pythonbrew.log import logger
+
+class UseCommand(Command):
+    name = "use"
+    usage = "%prog VERSION"
+    summary = "Using the given version of python"
+    
+    def run_command(self, options, args):
+        if not args:
+            logger.info("Unrecognized command line argument: argument not found.")
+            sys.exit(1)
+        pkg = Package(args[0])
+        pkgname = pkg.name
+        pkgdir = os.path.join(PATH_PYTHONS, pkgname)
+        if not os.path.isdir(pkgdir):
+            logger.info("`%s` is not installed." % pkgname)
+            sys.exit(1)
+        pkgbin = os.path.join(pkgdir,'bin')
+        
+        write_temp('%s:%s' % (PATH_BIN, pkgbin))
+        
+        logger.info("Using `%s`" % pkgname)
+
+UseCommand()
diff --git a/pythonbrew/define.py b/pythonbrew/define.py
index 6936fd3..12f5bc3 100644
--- a/pythonbrew/define.py
+++ b/pythonbrew/define.py
@@ -1,6 +1,6 @@
 import os
 
-VERSION = "0.6.2"
+VERSION = "0.6.3"
 
 if os.environ.has_key("PYTHONBREW_ROOT"):
     ROOT = os.environ["PYTHONBREW_ROOT"]
@@ -24,8 +24,10 @@ PATH_PATCHES_MACOSX_PYTHON25 = os.path.join(PATH_PATCHES_MACOSX,"python25")
 PATH_PATCHES_MACOSX_PYTHON24 = os.path.join(PATH_PATCHES_MACOSX,"python24")
 
 # file path
-PATH_BIN_PYTHONBREW = os.path.join(PATH_BIN,"pythonbrew")
-PATH_BIN_PYBREW = os.path.join(PATH_BIN,"pybrew") # pybrew is symlink as pythonbrew
+PATH_BIN_PYTHONBREW = os.path.join(PATH_BIN,'pythonbrew')
+PATH_BIN_PYBREW = os.path.join(PATH_BIN,'pybrew') # pybrew is symlink as pythonbrew
+PATH_ETC_CURRENT = os.path.join(PATH_ETC,'current')
+PATH_ETC_TEMP = os.path.join(PATH_ETC,'temp')
 
 # download setuptools url 
 DISTRIBUTE_SETUP_DLSITE = "http://python-distribute.org/distribute_setup.py"
diff --git a/pythonbrew/installer.py b/pythonbrew/installer.py
index 6d6a834..4277c03 100644
--- a/pythonbrew/installer.py
+++ b/pythonbrew/installer.py
@@ -142,6 +142,7 @@ class PythonInstaller(object):
             logger.error("Failed to install %s. See %s to see why." % (self.pkg.name, self.logfile))
             logger.info("  pythonbrew install --force %s" % self.pkg.version)
             sys.exit(1)
+        self.symlink()
         self.install_setuptools()
         logger.info("Installed %(pkgname)s successfully. Run the following command to switch to %(pkgname)s."
                     % {"pkgname":self.pkg.name})
@@ -239,7 +240,18 @@ class PythonInstaller(object):
             makedirs(self.install_dir)
         s = Subprocess(log=self.logfile, cwd=self.build_dir)
         s.check_call("make install")
-            
+    
+    def symlink(self):
+        install_dir = os.path.realpath(self.install_dir)
+        path_python = os.path.join(install_dir,'bin','python')
+        if not os.path.isfile(path_python):
+            path_python3 = os.path.join(install_dir,'bin','python3')
+            path_python3_0 = os.path.join(install_dir,'bin','python3.0')
+            if os.path.isfile(path_python3):
+                symlink(path_python3, path_python)
+            elif os.path.isfile(path_python3_0):
+                symlink(path_python3_0, path_python)
+    
     def install_setuptools(self):
         options = self.options
         pkgname = self.pkg.name
diff --git a/pythonbrew/scripts/bashrc b/pythonbrew/scripts/bashrc
index f4f2ed6..e4adb61 100644
--- a/pythonbrew/scripts/bashrc
+++ b/pythonbrew/scripts/bashrc
@@ -1,7 +1,36 @@
 PYTHONBREW_ROOT="@ROOT@"
 PYTHONBREW_ETC="$PYTHONBREW_ROOT/etc"
 
-export PATH=$PYTHONBREW_ROOT/bin:$PYTHONBREW_ROOT/pythons/current/bin:${PATH}
+__pythonbrew_set_default()
+{
+	PATH_PYTHONBREW="$PYTHONBREW_ROOT/bin"
+}
+
+__pythonbrew_set_path()
+{
+    PATH_WITHOUT_PYTHONBREW=$(printf $PATH | awk -v RS=: -v ORS=: "/${PYTHONBREW_ROOT//\//\/}/ {next} {print}" | sed -e 's#:$##')
+    export PATH=$PATH_PYTHONBREW:$PATH_WITHOUT_PYTHONBREW
+}
+
+__pythonbrew_set_temp_path()
+{
+    if [[ -s "$PYTHONBREW_ETC/temp" ]] ; then
+        source "$PYTHONBREW_ETC/temp"
+    else
+        __pythonbrew_set_default
+    fi
+    __pythonbrew_set_path
+}
+
+__pythonbrew_set_current_path()
+{
+    if [[ -s "$PYTHONBREW_ETC/current" ]] ; then
+        source "$PYTHONBREW_ETC/current"
+    else
+        __pythonbrew_set_default
+    fi
+    __pythonbrew_set_path
+}
 
 __pythonbrew_reload()
 {
@@ -10,11 +39,41 @@ __pythonbrew_reload()
     fi
 }
 
-pythonbrew()
+__pythonbrew_use()
 {
     command pythonbrew "$@"
-    case $1 in
-        update) __pythonbrew_reload ;; 
-    esac
-    hash -r
+    __pythonbrew_set_temp_path
 }
+
+__pythonbrew_switch()
+{
+    command pythonbrew "$@"
+    __pythonbrew_set_current_path
+}
+
+__pythonbrew_off()
+{
+    command pythonbrew "$@"
+    __pythonbrew_set_current_path
+}
+
+__pythonbrew_update()
+{
+    command pythonbrew "$@"
+    __pythonbrew_reload
+}
+
+pythonbrew()
+{
+    case $1 in
+        use) __pythonbrew_use "$@";;
+        switch) __pythonbrew_switch "$@" ;;
+        off) __pythonbrew_off "$@" ;;
+        update) __pythonbrew_update "$@" ;;
+        *) command pythonbrew "$@" ;;
+    esac
+    builtin hash -r
+}
+
+# main
+__pythonbrew_set_current_path
diff --git a/pythonbrew/util.py b/pythonbrew/util.py
index 62299fb..0ccda5b 100644
--- a/pythonbrew/util.py
+++ b/pythonbrew/util.py
@@ -4,11 +4,13 @@ import shutil
 import subprocess
 import re
 import posixpath
-from pythonbrew.define import PATH_BIN, PATH_PYTHONS
-from pythonbrew.exceptions import ShellCommandException
-from pythonbrew.log import logger
 import tarfile
 import platform
+from pythonbrew.define import PATH_BIN, PATH_PYTHONS, PATH_ETC_CURRENT,\
+    PATH_ETC_TEMP
+from pythonbrew.exceptions import ShellCommandException
+from pythonbrew.log import logger
+from subprocess import PIPE, Popen
 
 def size_format(b):
     kb = 1000
@@ -99,6 +101,7 @@ def off():
                 continue
             unlink("%s/%s" % (root, f))
     unlink("%s/current" % PATH_PYTHONS)
+    write_current(PATH_BIN)
 
 def split_leading_dir(path):
     path = str(path)
@@ -183,7 +186,25 @@ def unpack_downloadfile(content_type, download_file, target_dir):
         logger.error("Cannot determine archive format of %s" % download_file)
         return False
     return True
-    
+
+def get_current_python_path():
+    p = Popen('command -v python', stdout=PIPE, shell=True)
+    p.wait()
+    if p.returncode == 0:
+        return p.stdout.read().strip()
+    else:
+        return None
+
+def write_current(path):
+    fp = open(PATH_ETC_CURRENT, 'w')
+    fp.write('PATH_PYTHONBREW="%s"\n' % (path))
+    fp.close()
+
+def write_temp(path):
+    fp = open(PATH_ETC_TEMP, 'w')
+    fp.write('PATH_PYTHONBREW="%s"\n' % (path))
+    fp.close()
+
 class Subprocess(object):
     def __init__(self, log=None, shell=True, cwd=None, print_cmd=False):
         self._log = log