diff --git a/libexec/pyenv b/libexec/pyenv
index 9dd464a9..8173f6dc 100755
--- a/libexec/pyenv
+++ b/libexec/pyenv
@@ -54,6 +54,19 @@ else
 fi
 export PYENV_ROOT
 
+# Transfer PYENV_FILE_ARG (from shims) into PYENV_DIR.
+if [ -z "${PYENV_DIR}" ]; then
+  if [ -n "${PYENV_FILE_ARG}" ]; then
+    if [ -L "${PYENV_FILE_ARG}" ]; then
+      PYENV_DIR="$(abs_dirname "${PYENV_FILE_ARG}")"
+    else
+      PYENV_DIR="${PYENV_FILE_ARG%/*}"
+    fi
+    export PYENV_DIR
+    unset PYENV_FILE_ARG
+  fi
+fi
+
 if [ -z "${PYENV_DIR}" ]; then
   PYENV_DIR="$(pwd)"
 else
diff --git a/libexec/pyenv-rehash b/libexec/pyenv-rehash
index c266b1bf..a6451e0c 100755
--- a/libexec/pyenv-rehash
+++ b/libexec/pyenv-rehash
@@ -46,13 +46,13 @@ set -e
 [ -n "\$PYENV_DEBUG" ] && set -x
 
 program="\${0##*/}"
-if [ "\$program" = "python" ]; then
+if [[ "\$program" = "python"* ]]; then
   for arg; do
     case "\$arg" in
     -c* | -- ) break ;;
     */* )
       if [ -f "\$arg" ]; then
-        export PYENV_DIR="\${arg%/*}"
+        export PYENV_FILE_ARG="\$arg"
         break
       fi
       ;;
diff --git a/test/pyenv_ext.bats b/test/pyenv_ext.bats
index cc138cbe..fdae87fc 100644
--- a/test/pyenv_ext.bats
+++ b/test/pyenv_ext.bats
@@ -12,3 +12,19 @@ load test_helper
   PYENV_VERSION="2.7.10:system" run pyenv-prefix
   assert_success "${PYENV_ROOT}/versions/2.7.10:${PYENV_TEST_DIR}"
 }
+
+@test "should use dirname of file argument as PYENV_DIR" {
+  mkdir -p "${PYENV_TEST_DIR}/dir1"
+  touch "${PYENV_TEST_DIR}/dir1/file.py"
+  PYENV_FILE_ARG="${PYENV_TEST_DIR}/dir1/file.py" run pyenv echo PYENV_DIR
+  assert_output "${PYENV_TEST_DIR}/dir1"
+}
+
+@test "should follow symlink of file argument (#379, #404)" {
+  mkdir -p "${PYENV_TEST_DIR}/dir1"
+  mkdir -p "${PYENV_TEST_DIR}/dir2"
+  touch "${PYENV_TEST_DIR}/dir1/file.py"
+  ln -s "${PYENV_TEST_DIR}/dir1/file.py" "${PYENV_TEST_DIR}/dir2/symlink.py"
+  PYENV_FILE_ARG="${PYENV_TEST_DIR}/dir2/symlink.py" run pyenv echo PYENV_DIR
+  assert_output "${PYENV_TEST_DIR}/dir1"
+}