diff --git a/libexec/pyenv---version b/libexec/pyenv---version
index 778cf109..36883f91 100755
--- a/libexec/pyenv---version
+++ b/libexec/pyenv---version
@@ -12,7 +12,7 @@
 set -e
 [ -n "$PYENV_DEBUG" ] && set -x
 
-version="1.0.10"
+version="1.1.0"
 git_revision=""
 
 if cd "${BASH_SOURCE%/*}" 2>/dev/null && git remote -v 2>/dev/null | grep -q pyenv; then
diff --git a/libexec/pyenv-init b/libexec/pyenv-init
index 9bdcb9b7..df196295 100755
--- a/libexec/pyenv-init
+++ b/libexec/pyenv-init
@@ -86,8 +86,8 @@ mkdir -p "${PYENV_ROOT}/"{shims,versions}
 
 case "$shell" in
 fish )
-  echo "setenv PATH '${PYENV_ROOT}/shims' \$PATH"
-  echo "setenv PYENV_SHELL $shell"
+  echo "set -gx PATH '${PYENV_ROOT}/shims' \$PATH"
+  echo "set -gx PYENV_SHELL $shell"
 ;;
 * )
   echo 'export PATH="'${PYENV_ROOT}'/shims:${PATH}"'
@@ -97,10 +97,7 @@ esac
 
 completion="${root}/completions/pyenv.${shell}"
 if [ -r "$completion" ]; then
-  case "$shell" in
-  fish ) echo ". '$completion'" ;;
-  *    ) echo "source '$completion'" ;;
-  esac
+  echo "source '$completion'"
 fi
 
 if [ -z "$no_rehash" ]; then
@@ -117,7 +114,7 @@ function pyenv
 
   switch "\$command"
   case ${commands[*]}
-    . (pyenv "sh-\$command" \$argv|psub)
+    source (pyenv "sh-\$command" \$argv|psub)
   case '*'
     command pyenv "\$command" \$argv
   end
diff --git a/libexec/pyenv-sh-shell b/libexec/pyenv-sh-shell
index e02383f9..b38abbf3 100755
--- a/libexec/pyenv-sh-shell
+++ b/libexec/pyenv-sh-shell
@@ -2,7 +2,8 @@
 #
 # Summary: Set or show the shell-specific Python version
 #
-# Usage: pyenv shell <version>
+# Usage: pyenv shell <version>...
+#        pyenv shell -
 #        pyenv shell --unset
 #
 # Sets a shell-specific Python version by setting the `PYENV_VERSION'
@@ -12,6 +13,11 @@
 # <version> should be a string matching a Python version known to pyenv.
 # The special version string `system' will use your default system Python.
 # Run `pyenv versions' for a list of available Python versions.
+#
+# When `-` is passed instead of the version string, the previously set
+# version will be restored. With `--unset`, the `PYENV_VERSION`
+# environment variable gets unset, restoring the environment to the
+# state before the first `pyenv shell` call.
 
 set -e
 [ -n "$PYENV_DEBUG" ] && set -x
@@ -31,7 +37,7 @@ if [ -z "$versions" ]; then
     echo "pyenv: no shell-specific version configured" >&2
     exit 1
   else
-    echo "echo \"\$PYENV_VERSION\""
+    echo 'echo "$PYENV_VERSION"'
     exit
   fi
 fi
@@ -39,28 +45,76 @@ fi
 if [ "$versions" = "--unset" ]; then
   case "$shell" in
   fish )
+    echo 'set -gu PYENV_VERSION_OLD "$PYENV_VERSION"'
     echo "set -e PYENV_VERSION"
     ;;
   * )
+    echo 'PYENV_VERSION_OLD="$PYENV_VERSION"'
     echo "unset PYENV_VERSION"
     ;;
   esac
   exit
 fi
 
+if [ "$versions" = "-" ]; then
+  case "$shell" in
+  fish )
+    cat <<EOS
+if set -q PYENV_VERSION_OLD
+  if [ -n "\$PYENV_VERSION_OLD" ]
+    set PYENV_VERSION_OLD_ "\$PYENV_VERSION"
+    set -gx PYENV_VERSION "\$PYENV_VERSION_OLD"
+    set -gu PYENV_VERSION_OLD "\$PYENV_VERSION_OLD_"
+    set -e PYENV_VERSION_OLD_
+  else
+    set -gu PYENV_VERSION_OLD "\$PYENV_VERSION"
+    set -e PYENV_VERSION
+  end
+else
+  echo "pyenv: PYENV_VERSION_OLD is not set" >&2
+  false
+end
+EOS
+    ;;
+  * )
+    cat <<EOS
+if [ -n "\${PYENV_VERSION_OLD+x}" ]; then
+  if [ -n "\$PYENV_VERSION_OLD" ]; then
+    PYENV_VERSION_OLD_="\$PYENV_VERSION"
+    export PYENV_VERSION="\$PYENV_VERSION_OLD"
+    PYENV_VERSION_OLD="\$PYENV_VERSION_OLD_"
+    unset PYENV_VERSION_OLD_
+  else
+    PYENV_VERSION_OLD="\$PYENV_VERSION"
+    unset PYENV_VERSION
+  fi
+else
+  echo "pyenv: PYENV_VERSION_OLD is not set" >&2
+  false
+fi
+EOS
+    ;;
+  esac
+  exit
+fi
+
 # Make sure the specified version is installed.
 if pyenv-prefix "${versions[@]}" >/dev/null; then
   OLDIFS="$IFS"
   IFS=: version="${versions[*]}"
   IFS="$OLDIFS"
-  case "$shell" in
-  fish )
-    echo "setenv PYENV_VERSION \"${version}\""
-    ;;
-  * )
-    echo "export PYENV_VERSION=\"${version}\""
-    ;;
-  esac
+  if [ "$version" != "$PYENV_VERSION" ]; then
+    case "$shell" in
+    fish )
+      echo 'set -gu PYENV_VERSION_OLD "$PYENV_VERSION"'
+      echo "set -gx PYENV_VERSION \"$version\""
+      ;;
+    * )
+      echo 'PYENV_VERSION_OLD="$PYENV_VERSION"'
+      echo "export PYENV_VERSION=\"${version}\""
+      ;;
+    esac
+  fi
 else
   echo "false"
   exit 1
diff --git a/libexec/pyenv-which b/libexec/pyenv-which
index a8553e7d..9551f6cf 100755
--- a/libexec/pyenv-which
+++ b/libexec/pyenv-which
@@ -18,7 +18,7 @@ fi
 remove_from_path() {
   local path_to_remove="$1"
   local path_before
-  local result=":$PATH:"
+  local result=":${PATH//\~/$HOME}:"
   while [ "$path_before" != "$result" ]; do
     path_before="$result"
     result="${result//:$path_to_remove:/:}"
diff --git a/src/configure b/src/configure
index 86e25ac1..10d0ff57 100755
--- a/src/configure
+++ b/src/configure
@@ -21,6 +21,9 @@ case "$(uname -s)" in
 Darwin* )
   host_os="darwin$(uname -r)"
   ;;
+FreeBSD* )
+  host_os="freebsd$(uname -r)"
+  ;;
 OpenBSD* )
   host_os="openbsd$(uname -r)"
   ;;
diff --git a/test/init.bats b/test/init.bats
old mode 100644
new mode 100755
index c7026f65..ead63d82
--- a/test/init.bats
+++ b/test/init.bats
@@ -47,7 +47,7 @@ OUT
   root="$(cd $BATS_TEST_DIRNAME/.. && pwd)"
   run pyenv-init - fish
   assert_success
-  assert_line ". '${root}/test/../libexec/../completions/pyenv.fish'"
+  assert_line "source '${root}/test/../libexec/../completions/pyenv.fish'"
 }
 
 @test "fish instructions" {
@@ -73,7 +73,7 @@ OUT
   export PATH="${BATS_TEST_DIRNAME}/../libexec:/usr/bin:/bin:/usr/local/bin"
   run pyenv-init - fish
   assert_success
-  assert_line 0 "setenv PATH '${PYENV_ROOT}/shims' \$PATH"
+  assert_line 0 "set -gx PATH '${PYENV_ROOT}/shims' \$PATH"
 }
 
 @test "can add shims to PATH more than once" {
@@ -87,7 +87,7 @@ OUT
   export PATH="${PYENV_ROOT}/shims:$PATH"
   run pyenv-init - fish
   assert_success
-  assert_line 0 "setenv PATH '${PYENV_ROOT}/shims' \$PATH"
+  assert_line 0 "set -gx PATH '${PYENV_ROOT}/shims' \$PATH"
 }
 
 @test "outputs sh-compatible syntax" {
diff --git a/test/shell.bats b/test/shell.bats
index 30bf127b..82383aad 100644
--- a/test/shell.bats
+++ b/test/shell.bats
@@ -20,14 +20,34 @@ load test_helper
   assert_success 'echo "$PYENV_VERSION"'
 }
 
+@test "shell revert" {
+  PYENV_SHELL=bash run pyenv-sh-shell -
+  assert_success
+  assert_line 0 'if [ -n "${PYENV_VERSION_OLD+x}" ]; then'
+}
+
+@test "shell revert (fish)" {
+  PYENV_SHELL=fish run pyenv-sh-shell -
+  assert_success
+  assert_line 0 'if set -q PYENV_VERSION_OLD'
+}
+
 @test "shell unset" {
   PYENV_SHELL=bash run pyenv-sh-shell --unset
-  assert_success "unset PYENV_VERSION"
+  assert_success
+  assert_output <<OUT
+PYENV_VERSION_OLD="\$PYENV_VERSION"
+unset PYENV_VERSION
+OUT
 }
 
 @test "shell unset (fish)" {
   PYENV_SHELL=fish run pyenv-sh-shell --unset
-  assert_success "set -e PYENV_VERSION"
+  assert_success
+  assert_output <<OUT
+set -gu PYENV_VERSION_OLD "\$PYENV_VERSION"
+set -e PYENV_VERSION
+OUT
 }
 
 @test "shell change invalid version" {
@@ -42,11 +62,19 @@ SH
 @test "shell change version" {
   mkdir -p "${PYENV_ROOT}/versions/1.2.3"
   PYENV_SHELL=bash run pyenv-sh-shell 1.2.3
-  assert_success 'export PYENV_VERSION="1.2.3"'
+  assert_success
+  assert_output <<OUT
+PYENV_VERSION_OLD="\$PYENV_VERSION"
+export PYENV_VERSION="1.2.3"
+OUT
 }
 
 @test "shell change version (fish)" {
   mkdir -p "${PYENV_ROOT}/versions/1.2.3"
   PYENV_SHELL=fish run pyenv-sh-shell 1.2.3
-  assert_success 'setenv PYENV_VERSION "1.2.3"'
+  assert_success
+  assert_output <<OUT
+set -gu PYENV_VERSION_OLD "\$PYENV_VERSION"
+set -gx PYENV_VERSION "1.2.3"
+OUT
 }