diff --git a/README.md b/README.md
index 8cb5762..271d49f 100644
--- a/README.md
+++ b/README.md
@@ -78,6 +78,23 @@ version.
       venv33 (created from /home/yyuu/.pyenv/versions/3.3.3)
 
 
+### Activate virtualenv
+
+Some external tools (e.g. [jedi](https://github.com/davidhalter/jedi)) might require you to `activate` the virtualenv.
+`pyenv activate` lets you to activate the virtualenv into your shell.
+
+    $ pyenv activate venv27
+
+`pyenv activate` acts almost like following commands.
+
+    $ pyenv shell venv27
+    $ source "$(pyenv prefix venv27)/bin/activate"
+
+You can deactivate the activate'd virtualenv by `pyenv deactivate`.
+
+    $ pyenv deactivate
+
+
 ### Special environment variables
 
 You can set certain environment variables to control the pyenv-virtualenv.
diff --git a/bin/pyenv-sh-activate b/bin/pyenv-sh-activate
new file mode 100755
index 0000000..33f2352
--- /dev/null
+++ b/bin/pyenv-sh-activate
@@ -0,0 +1,48 @@
+#!/usr/bin/env bash
+#
+# Summary: Activate virtual environment
+#
+# Usage: pyenv activate <virtualenv>
+#        pyenv activate --unset
+#
+# Activate a Python virtualenv environment in current shell.
+# This acts almost as same as `pyenv shell`, but this invokes the `activate`
+# script in your shell.
+#
+# <virtualenv> should be a string matching a Python version known to pyenv.
+
+set -e
+[ -n "$PYENV_DEBUG" ] && set -x
+
+# Provide pyenv completions
+if [ "$1" = "--complete" ]; then
+  echo --unset
+  exec pyenv-virtualenvs --bare
+fi
+
+versions=("$@")
+shell="$(basename "${PYENV_SHELL:-$SHELL}")"
+
+if [ -z "$versions" ]; then
+  OLDIFS="$IFS"
+  IFS=: versions=($(pyenv-version-name))
+  IFS="$OLDIFS"
+fi
+
+if [ "$1" = "--unset" ]; then
+  echo "pyenv deactivate"
+  exit
+fi
+
+if [ "${#versions[@]}" -gt 1 ]; then
+  echo "pyenv-virtualenv: cannot activate multiple versions at once: ${versions[@]}" 1>&2
+  exit 1
+fi
+
+pyenv-virtualenv-prefix "${versions}" 1>/dev/null
+
+echo "pyenv shell \"${versions}\""
+case "$shell" in
+fish ) echo ". \"$(pyenv-prefix "${versions}")/bin/activate.fish\"" ;;
+*    ) echo "source \"$(pyenv-prefix "${versions}")/bin/activate\"" ;;
+esac
diff --git a/bin/pyenv-sh-deactivate b/bin/pyenv-sh-deactivate
new file mode 100755
index 0000000..a0d2dd9
--- /dev/null
+++ b/bin/pyenv-sh-deactivate
@@ -0,0 +1,17 @@
+#!/usr/bin/env bash
+#
+# Summary: Deactivate virtual environment
+#
+# Usage: pyenv deactivate
+#
+# Deactivate a Python virtual environment.
+
+set -e
+[ -n "$PYENV_DEBUG" ] && set -x
+
+shell="$(basename "${PYENV_SHELL:-$SHELL}")"
+case "$shell" in
+fish ) echo "functions -q deactivate; and deactivate";;
+*    ) echo "declare -f deactivate 1>/dev/null 2>&1 && deactivate";;
+esac
+echo "pyenv shell --unset"
diff --git a/bin/pyenv-virtualenv b/bin/pyenv-virtualenv
index ed63e4a..6909b17 100755
--- a/bin/pyenv-virtualenv
+++ b/bin/pyenv-virtualenv
@@ -230,7 +230,7 @@ for option in "${OPTIONS[@]}"; do
 done
 
 if [[ "${#ARGUMENTS[@]}" == 0 ]]; then
-  echo "pyenv: no virtualenv name given." 1>&2
+  echo "pyenv-virtualenv: no virtualenv name given." 1>&2
   exit 1
 elif [[ "${#ARGUMENTS[@]}" == 1 ]]; then
   # If only one argument given, use current version as source version
@@ -312,7 +312,7 @@ done
 # the --force option was specified.
 if [ -d "${VIRTUALENV_PATH}/bin" ]; then
   if [ -z "$FORCE" ]; then
-    echo "pyenv: ${VIRTUALENV_PATH} already exists" 1>&2
+    echo "pyenv-virtualenv: ${VIRTUALENV_PATH} already exists" 1>&2
     read -p "continue with installation? (y/N) "
 
     case "$REPLY" in
diff --git a/bin/pyenv-virtualenv-prefix b/bin/pyenv-virtualenv-prefix
index a7d49ac..3cc56de 100755
--- a/bin/pyenv-virtualenv-prefix
+++ b/bin/pyenv-virtualenv-prefix
@@ -39,7 +39,7 @@ for version in "${versions[@]}"; do
       VIRTUALENV_PREFIX_PATHS=("${VIRTUALENV_PREFIX_PATHS[@]}" "$VIRTUALENV_PREFIX_PATH")
     fi
   else
-    echo "pyenv: version \`${version}' is not a virtualenv" 1>&2
+    echo "pyenv-virtualenv: version \`${version}' is not a virtualenv" 1>&2
     exit 1
   fi
 done