diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index fdabf07..0e4a485 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -29,12 +29,10 @@ jobs:
         with:
           ruby-version: '2.6.x'
 
-      - uses: actions/setup-python@v1
-        with:
-          python-version: '3.7.x'
-
       - name: Checkout
         uses: actions/checkout@v2
+        with:
+          fetch-depth: 0
 
       - name: Bundle Caching
         id: bundle-cache
@@ -45,21 +43,7 @@ jobs:
           restore-keys: |
             ${{ runner.os }}-gems-
 
-      - name: Get pip cache path
-        id: get-pip-cache-path
-        run: |
-          echo "::set-output name=path::`pip show pip | grep "Location" | awk '{print $2}'`"
-
-      - name: Pip caching
-        id: pip-cache
-        uses: actions/cache@v1
-        with:
-          path: ${{ steps.get-pip-cache-path.outputs.path }}
-          key: ${{ runner.os }}-pip-${{ hashFiles('**/requirements.txt') }}
-          restore-keys: |
-            ${{ runner.os }}-pip-
-
-      - name: Install gnu-coreutils for macOS
+      - name: Install GNU-Coreutils(for macOS)
         if: runner.os == 'macOS'
         run: |
           brew install coreutils
@@ -78,11 +62,6 @@ jobs:
         run: |
           bundle install --local
 
-      - name: Pip installing
-        if: steps.pip-cache.outputs.cache-hit != 'true'
-        run: |
-          pip install -r _scripts/py/requirements.txt
-
       - name: Build Site
         run: |
           bash tools/build.sh
diff --git a/.travis.yml b/.travis.yml
index 8b49999..ab2400d 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -4,11 +4,7 @@ dist: bionic
 language: ruby
 rvm: 2.6.5
 
-before_install:
-  - pyenv global 3.7.6
-
 install:
-  - pip install -r _scripts/py/requirements.txt
   - bundle install --path vendor/bundle --quiet
 
 addons:
diff --git a/_includes/panel.html b/_includes/panel.html
index a36c7a5..6e4e85f 100644
--- a/_includes/panel.html
+++ b/_includes/panel.html
@@ -9,40 +9,51 @@
 <div id="panel-wrapper" class="col-xl-3 pl-2 text-muted topbar-down">
 
   <div class="access">
-  {% assign lastmod_list = "" | split: "" %}
-  {% assign index = 0 %}
 
-  {% for post in site.posts %}
-    {% if post.seo.date_modified > post.date and post.seo.date_modified != nil %}
-      {% capture item %}
-        {{ post.seo.date_modified }}::{{ index }}
+  {% if site.data.updates %}
+    {% assign MAX_SIZE = 5 %}
+    {% assign sum = 0 %}
+    {% assign sort_list = "" | split: "" %}
+
+    {% for entry in site.data.updates %}
+      {% capture elem %}
+        {{- entry.lastmod -}}::{{- entry.filename -}}
       {% endcapture %}
-      {% assign lastmod_list = lastmod_list | push: item %}
-    {% endif %}
-    {% assign index = index | plus: 1 %}
-  {% endfor %}
+      {% assign sort_list = sort_list | push: elem %}
+    {% endfor %}
+
+    {% assign sort_list = sort_list | sort | reverse %}
+
+    {% if sort_list.size > 0 %}
 
-  {% if lastmod_list.size > 0 %}
     <div id="access-lastmod" class="post">
       <h3 data-toc-skip>
         {{- site.data.label.panel.lastmod -}}
       </h3>
       <ul class="post-content pl-0 pb-1 ml-1 mt-2">
-    {% assign MAX_SIZE = 5 %}
-    {% assign sum = 0 %}
-    {% assign lastmod_list = lastmod_list | sort | reverse %}
-    {% for item in lastmod_list %}
-      {% assign index = item | split: "::" | last | plus: 0 %}
-      {% assign post = site.posts[index] %}
-        <li><a href="{{ post.url | prepend: site.baseurl }}">{{ post.title }}</a></li>
-      {% assign sum = sum | plus: 1 %}
-      {% if sum >= MAX_SIZE %}
-        {% break %}
-      {% endif %}
-    {% endfor %}
+
+      {% for item in sort_list %}
+        {% assign post_url = item | split: "::" | last | prepend: "/posts/" | append: "/" %}
+        {% assign post = site.posts | where: "url", post_url | first %}
+
+        {% if post %}
+          {% assign url = post.url | prepend: site.baseurl %}
+
+          <li><a href="{{ url }}">{{ post.title }}</a></li>
+
+          {% assign sum = sum | plus: 1 %}
+          {% if sum >= MAX_SIZE %} {% break %} {% endif %}
+
+        {% endif %}
+
+      {% endfor %}
+
       </ul>
     </div><!-- #access-lastmod -->
-  {% endif %}
+
+    {% endif %}
+
+  {% endif %} <!-- site.data.updates -->
 
     <div id="access-tags">
       <h3 data-toc-skip>
diff --git a/_layouts/post.html b/_layouts/post.html
index dddb2e1..b84cd6c 100644
--- a/_layouts/post.html
+++ b/_layouts/post.html
@@ -35,14 +35,20 @@ layout: default
         </div>
 
         <!-- lastmod -->
-        {% if page.seo.date_modified > page.date %}
+        {%- capture filename -%}
+          {{ page.url | split: "/" | last }}
+        {%- endcapture -%}
+
+        {% assign record = site.data.updates | where: "filename", filename | first %}
+
+        {% if record %}
         <div>
           Updated
           <span class="timeago lastmod"
             data-toggle="tooltip" data-placement="bottom"
-             title="{{ page.seo.date_modified | date: site.data.date_format.tooltip }}">
-            {{ page.seo.date_modified | date: site.data.date_format.post }}
-            <i class="unloaded">{{ page.seo.date_modified | date_to_xmlschema}}</i>
+             title="{{ record.lastmod | date: site.data.date_format.tooltip }}">
+            {{ record.lastmod | date: site.data.date_format.post }}
+            <i class="unloaded">{{ record.lastmod | date_to_xmlschema}}</i>
           </span>
         </div>
         {% endif %}
diff --git a/_scripts/py/init_all.py b/_scripts/py/init_all.py
deleted file mode 100755
index 1e029c3..0000000
--- a/_scripts/py/init_all.py
+++ /dev/null
@@ -1,18 +0,0 @@
-#!/usr/bin/env python
-# -*- coding: utf-8 -*-
-
-"""
-Automatic invokes all initial scripts for project.
-v2.0
-https://github.com/cotes2020/jekyll-theme-chirpy
-© 2018-2019 Cotes Chung
-Licensed under MIT
-"""
-
-import update_posts_lastmod
-import pages_generator
-
-
-update_posts_lastmod
-
-pages_generator
diff --git a/_scripts/py/pages_generator.py b/_scripts/py/pages_generator.py
deleted file mode 100755
index 0302e8a..0000000
--- a/_scripts/py/pages_generator.py
+++ /dev/null
@@ -1,205 +0,0 @@
-#!/usr/bin/env python
-# -*- coding: utf-8 -*-
-
-'''
-Generates HTML pages for Categories and Tags in posts.
-
-Dependencies:
-  - git
-  - ruamel.yaml
-
-v2.0
-https://github.com/cotes2020/jekyll-theme-chirpy
-© 2018-2019 Cotes Chung
-MIT License
-'''
-
-
-import os
-import shutil
-import sys
-import subprocess
-
-from ruamel.yaml import YAML
-from utils.common import get_yaml
-from utils.common import get_makrdown_files
-from utils.common import check_py_version
-
-
-DRAFTS_DIR = '_drafts'
-POSTS_DIR = ['_posts']
-
-CATEGORIES_DIR = 'categories'
-CATEGORY_LAYOUT = 'category'
-
-TAG_DIR = 'tags'
-TAG_LAYOUT = 'tag'
-
-LEVEL = 3  # Tree level for current script file.
-
-
-def help():
-    print("Usage: "
-          "   python pages_generator.py [Option]\n\n"
-          "Options:\n"
-          "   -d, --drafts         Enable drafts\n"
-          "   -v, --verbose        Print verbose logs\n")
-
-
-def get_path(dir):
-    path = os.path.abspath(__file__)
-    count = LEVEL
-    r_index = len(path)
-    while r_index > 0:
-        r_index -= 1
-        if (path[r_index] == '/' or path[r_index] == '\\'):
-            count -= 1
-            if count == 0:
-                return path[:r_index + 1] + dir
-
-
-def get_categories():
-    all_categories = []
-    yaml = YAML()
-
-    for dir in POSTS_DIR:
-        path = get_path(dir)
-        posts = get_makrdown_files(path)
-
-        for file in posts:
-
-            meta = yaml.load(get_yaml(file)[0])
-
-            if 'category' in meta:
-                if type(meta['category']) == list:
-                    err_msg = (
-                        "[Error] File {} 'category' type"
-                        " can not be LIST!").format(file)
-                    raise Exception(err_msg)
-                else:
-                    if meta['category'] not in all_categories:
-                        all_categories.append(meta['category'])
-            else:
-                if 'categories' in meta:
-                    if type(meta['categories']) == str:
-                        error_msg = (
-                            "[Error] File {} 'categories' type"
-                            " can not be STR!").format(file)
-                        raise Exception(error_msg)
-
-                    for ctg in meta['categories']:
-                        if ctg not in all_categories:
-                            all_categories.append(ctg)
-                else:
-                    err_msg = (
-                        "[Error] File:{} at least "
-                        "have one category.").format(file)
-                    print(err_msg)
-
-    return all_categories
-
-
-def generate_category_pages(is_verbose):
-    categories = get_categories()
-
-    if len(categories) <= 0:
-        return
-
-    path = get_path(CATEGORIES_DIR)
-
-    if os.path.exists(path):
-        shutil.rmtree(path)
-
-    os.makedirs(path)
-
-    for category in categories:
-        new_page = path + '/' + category.replace(' ', '-').lower() + '.html'
-        with open(new_page, 'w+', encoding='utf-8') as html:
-            html.write("---\n")
-            html.write("layout: {}\n".format(CATEGORY_LAYOUT))
-            html.write("title: {}\n".format(category))
-            html.write("category: {}\n".format(category))
-            html.write("---")
-
-            if is_verbose:
-                print("[INFO] Created page: " + new_page)
-
-    change = subprocess.getoutput("git status categories -s")
-    if change:
-        print("[INFO] Succeed! {} category-pages created."
-              .format(len(categories)))
-
-
-def get_all_tags():
-    all_tags = []
-    yaml = YAML()
-
-    for dir in POSTS_DIR:
-        path = get_path(dir)
-        posts = get_makrdown_files(path)
-
-        for file in posts:
-            meta = yaml.load(get_yaml(file)[0])
-
-            if 'tags' in meta:
-                for tag in meta['tags']:
-                    if tag not in all_tags:
-                        all_tags.append(tag)
-            else:
-                raise Exception("Didn't find 'tags' in post '{}' !"
-                                .format(file))
-
-    return all_tags
-
-
-def generate_tag_pages(is_verbose):
-    all_tags = get_all_tags()
-
-    if len(all_tags) <= 0:
-        return
-
-    tag_path = get_path(TAG_DIR)
-
-    if os.path.exists(tag_path):
-        shutil.rmtree(tag_path)
-
-    os.makedirs(tag_path)
-
-    for tag in all_tags:
-        tag_page = tag_path + '/' + tag.replace(' ', '-').lower() + '.html'
-        with open(tag_page, 'w+', encoding='utf-8') as html:
-            html.write("---\n")
-            html.write("layout: {}\n".format(TAG_LAYOUT))
-            html.write("title: {}\n".format(tag))
-            html.write("tag: {}\n".format(tag))
-            html.write("---")
-
-            if is_verbose:
-                print("[INFO] Created page: " + tag_page)
-
-    change = subprocess.getoutput("git status tags -s")
-    if change:
-        print("[INFO] Succeed! {} tag-pages created.".format(len(all_tags)))
-
-
-def main():
-    check_py_version()
-
-    is_verbose = False
-
-    if len(sys.argv) > 1:
-        for arg in sys.argv:
-            if arg != sys.argv[0]:
-                if arg == '-d' or arg == '--drafts':
-                    POSTS_DIR.insert(0, DRAFTS_DIR)
-                elif arg == '-v' or arg == '--verbose':
-                    is_verbose = True
-                else:
-                    help()
-                    return
-
-    generate_category_pages(is_verbose)
-    generate_tag_pages(is_verbose)
-
-
-main()
diff --git a/_scripts/py/requirements.txt b/_scripts/py/requirements.txt
deleted file mode 100644
index a363a51..0000000
--- a/_scripts/py/requirements.txt
+++ /dev/null
@@ -1,2 +0,0 @@
-ruamel.yaml==0.16.5
-ruamel.yaml.clib==0.1.2
diff --git a/_scripts/py/update_posts_lastmod.py b/_scripts/py/update_posts_lastmod.py
deleted file mode 100755
index 2a24ab1..0000000
--- a/_scripts/py/update_posts_lastmod.py
+++ /dev/null
@@ -1,174 +0,0 @@
-#!/usr/bin/env python
-# -*- coding: utf-8 -*-
-
-"""
-Update (or create if not existed) field 'seo.date_modified'
-in posts' Front Matter by their latest git commit date.
-
-Dependencies:
-  - git
-  - ruamel.yaml
-
-v2.0
-https://github.com/cotes2020/jekyll-theme-chirpy
-© 2018-2019 Cotes Chung
-Licensed under MIT
-"""
-
-import sys
-import os
-import getopt
-import subprocess
-import shutil
-import datetime
-import time
-
-from enum import Enum
-from ruamel.yaml import YAML
-
-from utils.common import get_yaml
-from utils.common import get_makrdown_files
-from utils.common import check_py_version
-
-
-Date = Enum('Date', ('GIT', 'FS'))
-
-POSTS_PATH = '_posts'
-
-
-def help():
-    print("Usage: "
-          "   python update_posts_lastmod.py [options]\n"
-          "Options:\n"
-          "   -f, --file  <file path>        Read a file.\n"
-          "   -d, --dir   <directory path>   Read from a directory.\n"
-          "   -h, --help                     Print help information\n"
-          "   -v, --verbose                  Print verbose logs\n"
-          "   -t, --datetime  < git | fs >   Chose post's datetime source, "
-          "'git' for git-log, 'fs' for filesystem, default to 'git'.\n")
-
-
-def update_lastmod(posts, verbose, date):
-    count = 0
-    yaml = YAML()
-
-    for post in posts:
-
-        lastmod = ''
-
-        if date == Date.GIT:
-            git_log_count = subprocess.getoutput(
-                "git log --pretty=%ad \"{}\" | wc -l".format(post))
-
-            if git_log_count == "1":
-                continue
-
-            git_lastmod = subprocess.getoutput(
-                "git log -1 --pretty=%ad --date=iso \"{}\"".format(post))
-
-            if not git_lastmod:
-                continue
-
-            lates_commit = subprocess.check_output(
-                ['git', 'log', '-1', '--pretty=%B', post]).decode('utf-8')
-
-            if "[Automation]" in lates_commit and "Lastmod" in lates_commit:
-                continue
-
-            lastmod = git_lastmod
-
-        elif date == Date.FS:
-            t = os.path.getmtime(post)
-            dt = datetime.datetime.fromtimestamp(t)
-            lastmod = dt.strftime('%F %T') + time.strftime(' %z')
-
-        frontmatter, line_num = get_yaml(post)
-        meta = yaml.load(frontmatter)
-
-        if 'seo' in meta:
-            if ('date_modified' in meta['seo'] and
-                    meta['seo']['date_modified'] == lastmod):
-                continue
-            else:
-                meta['seo']['date_modified'] = lastmod
-        else:
-            meta.insert(line_num, 'seo', dict(date_modified=lastmod))
-
-        output = 'new.md'
-        if os.path.isfile(output):
-            os.remove(output)
-
-        with open(output, 'w', encoding='utf-8') as new, \
-                open(post, 'r', encoding='utf-8') as old:
-            new.write("---\n")
-            yaml.dump(meta, new)
-            new.write("---\n")
-            line_num += 2
-
-            lines = old.readlines()
-
-            for line in lines:
-                if line_num > 0:
-                    line_num -= 1
-                    continue
-                else:
-                    new.write(line)
-
-        shutil.move(output, post)
-        count += 1
-
-        if verbose:
-            print("[INFO] update 'lastmod' for:" + post)
-
-    if count > 0:
-        print("[INFO] Success to update lastmod for {} post(s).".format(count))
-
-
-def main(argv):
-    check_py_version()
-
-    specific = False
-    posts = []
-    verbose = False
-    date = Date.GIT
-
-    try:
-        opts, args = getopt.getopt(
-            argv, "hf:d:vt:",
-            ["file=", "dir=", "help", "verbose", "datetime="])
-    except getopt.GetoptError:
-        help()
-        sys.exit(2)
-
-    for opt, arg in opts:
-        if opt == '-h':
-            help()
-            sys.exit()
-
-        elif opt == '-f' or opt == '--file':
-            posts.append(arg)
-            specific = True
-
-        elif opt == '-d' or opt == '--dir':
-            posts = get_makrdown_files(arg)
-            specific = True
-
-        elif opt == '-v' or opt == '--verbose':
-            verbose = True
-
-        elif opt == '-t' or opt == '--datetime':
-            if arg == 'git':
-                date = Date.GIT
-            elif arg == 'fs':
-                date = Date.FS
-            else:
-                help()
-                sys.exit(2)
-
-    if not specific:
-        posts = get_makrdown_files(POSTS_PATH)
-
-    update_lastmod(posts, verbose, date)
-
-
-main(sys.argv[1:])
diff --git a/_scripts/py/utils/common.py b/_scripts/py/utils/common.py
deleted file mode 100644
index 7b8a924..0000000
--- a/_scripts/py/utils/common.py
+++ /dev/null
@@ -1,57 +0,0 @@
-#!/usr/bin/env python
-# -*- coding: utf-8 -*-
-
-'''
-Common functions to other scripts.
-
-v2.0
-https://github.com/cotes2020/jekyll-theme-chirpy
-© 2018-2019 Cotes Chung
-MIT License
-'''
-
-import sys
-import os
-import glob
-
-
-def get_yaml(path):
-    """
-    Return the Yaml block of a post and the linenumbers of it.
-    """
-    end = False
-    yaml = ""
-    num = 0
-
-    with open(path, 'r', encoding='utf-8') as f:
-        for line in f.readlines():
-            if line.strip() == '---':
-                if end:
-                    break
-                else:
-                    end = True
-                    continue
-            else:
-                num += 1
-
-            yaml += line
-
-    return yaml, num
-
-
-def get_makrdown_files(path):
-    MD_EXTENSIONS = ["md", "markdown", "markdn", "mdown"]
-    ret_files = []
-
-    for extension in MD_EXTENSIONS:
-        ret_files.extend(glob.glob(os.path.join(path, "*." + extension)))
-
-    return ret_files
-
-
-def check_py_version():
-    if not sys.version_info.major == 3 and sys.version_info.minor >= 5:
-        print("WARNING: This script requires Python 3.5 or higher, "
-              "however you are using Python {}.{}."
-              .format(sys.version_info.major, sys.version_info.minor))
-        sys.exit(1)
diff --git a/_scripts/sh/create_pages.sh b/_scripts/sh/create_pages.sh
new file mode 100755
index 0000000..7ad6b8d
--- /dev/null
+++ b/_scripts/sh/create_pages.sh
@@ -0,0 +1,142 @@
+#!/usr/local/bin/bash
+#
+# Create HTML pages for Categories and Tags in posts.
+#
+# Usage:
+#     Call from the '_posts' sibling directory.
+#
+# v2.2
+# https://github.com/cotes2020/jekyll-theme-chirpy
+# © 2020 Cotes Chung
+# Published under MIT License
+
+set -eu
+
+TYPE_CATEGORY=0
+TYPE_TAG=1
+
+category_count=0
+tag_count=0
+
+read_categories() {
+  if [[ $(grep "categories:" $1) ]]; then
+    grep "categories:" $1 | head -1 | sed 's/categories: *//;s/\[//;s/\]//;s/, */,/g;s/"//g'
+  elif [[  $(grep "category:" $1) ]]; then
+    grep "category:" $1 | head -1 | sed 's/category: *//;s/\[//;s/\]//;s/, */,/g;s/"//g'
+  fi
+}
+
+
+read_tags() {
+  grep "tags:" $1 | head -1 | sed 's/tags: *//;s/\[//;s/\]//;s/, */,/g;s/"//g'
+}
+
+
+init() {
+  if [[ -d categories ]]; then
+    rm -rf categories
+  fi
+
+  if [[ -d tags ]]; then
+    rm -rf tags
+  fi
+
+  mkdir categories tags
+}
+
+
+create_category() {
+  local _name=$1
+  local _filepath="categories/$(echo $_name | sed 's/ /-/g' | awk '{print tolower($0)}').html"
+
+  if [[ ! -f $_filepath ]]; then
+    echo "---" > $_filepath
+    echo "layout: category" >> $_filepath
+    echo "title: $_name" >> $_filepath
+    echo "category: $_name" >> $_filepath
+    echo "---" >> $_filepath
+
+    ((category_count=category_count+1))
+  fi
+}
+
+
+create_tag() {
+  local _name=$1
+  local _filepath="tags/$( echo $_name | sed "s/ /-/g;s/'//g" | awk '{print tolower($0)}' ).html"
+
+  if [[ ! -f $_filepath ]]; then
+
+    echo "---" > $_filepath
+    echo "layout: tag" >> $_filepath
+    echo "title: $_name" >> $_filepath
+    echo "tag: $_name" >> $_filepath
+    echo "---" >> $_filepath
+
+    ((tag_count=tag_count+1))
+  fi
+}
+
+
+#########################################
+# Create HTML pages for Categories/Tags.
+# Arguments:
+#   $1 - an array string
+#   $2 - type specified option
+#########################################
+create_pages() {
+  if [[ $1 == '' ]]; then
+    exit 0
+  fi
+
+  # split string to array
+  IFS_BAK=$IFS
+  IFS=','
+  local _string=$1
+
+  case $2 in
+
+    $TYPE_CATEGORY)
+      for i in ${_string#,}; do
+        create_category $i
+      done
+      ;;
+
+    $TYPE_TAG)
+      for i in ${_string#,}; do
+        create_tag $i
+      done
+      ;;
+
+    *)
+      ;;
+
+    esac
+
+    IFS=$IFS_BAK
+  }
+
+
+main() {
+  init
+
+  for _file in $(ls "_posts")
+  do
+    local _path="_posts/$_file"
+    local _categories=$(read_categories "$_path")
+    local _tags=$(read_tags "$_path")
+
+    create_pages "$_categories" $TYPE_CATEGORY
+    create_pages "$_tags" $TYPE_TAG
+  done
+
+  if [[ $category_count -gt 0 ]]; then
+    echo "[INFO] Succeed! $category_count category-pages created."
+  fi
+
+  if [[ $tag_count -gt 0 ]]; then
+    echo "[INFO] Succeed! $tag_count tag-pages created."
+  fi
+}
+
+main
diff --git a/_scripts/sh/dump_lastmod.sh b/_scripts/sh/dump_lastmod.sh
new file mode 100755
index 0000000..ab45706
--- /dev/null
+++ b/_scripts/sh/dump_lastmod.sh
@@ -0,0 +1,89 @@
+#!/bin/bash
+#
+# Find out the posts that have been modified and record
+# its lastmod information to file '_data/updates.yml'
+#
+# Usage:
+#     Call from the '_posts' sibling directory.
+#
+# v2.2
+# https://github.com/cotes2020/jekyll-theme-chirpy
+# © 2020 Cotes Chung
+# Published under MIT License
+
+set -eu
+
+POST_DIR=_posts
+OUTPUT_DIR=_data
+OUTPUT_FILE=updates.yml
+
+
+_init() {
+  if [[ ! -d "$OUTPUT_DIR" ]]; then
+    mkdir "$OUTPUT_DIR"
+  fi
+
+  if [[ -f "$OUTPUT_DIR/$OUTPUT_FILE" ]]; then
+    rm -f "$OUTPUT_DIR/$OUTPUT_FILE"
+  fi
+
+  touch "$OUTPUT_DIR/$OUTPUT_FILE"
+}
+
+
+_has_changed() {
+  local _log_count=`git log --pretty=%ad $1 | wc -l | sed 's/ *//'`
+  _log_count=$(($_log_count + 0))
+
+  if [[ $_log_count > 1 ]]; then
+    return 0 # true
+  fi
+
+  return 1 # false
+}
+
+
+###################################
+# Storage the posts' lastmod.
+#
+# Args:
+#     - $1 the post's filename
+#     - $2 the post's filepath
+# Output:
+#     the file '_data/updates.yml'
+###################################
+_dump() {
+  local _lasmod="`git log -1 --pretty=%ad --date=iso $2`"
+
+  echo "-" >> "$OUTPUT_DIR/$OUTPUT_FILE"
+  echo "  filename: '$1'" >> "$OUTPUT_DIR/$OUTPUT_FILE"
+  echo "  lastmod: '$_lasmod'" >> "$OUTPUT_DIR/$OUTPUT_FILE"
+}
+
+
+main() {
+
+  _init
+
+  local _count=0
+
+  for _file in $(ls -r "$POST_DIR")
+  do
+    _filepath="$POST_DIR/$_file"
+    _filename="${_file%.*}"     # jekyll cannot read the extension of a file, so omit it.
+    _filename=${_filename:11}   # remove the date
+
+    if _has_changed "$_filepath"; then
+      _dump "$_filename" "$_filepath"
+      ((_count=_count+1))
+    fi
+
+  done
+
+  if [[ $_count > 0 ]]; then
+    echo "[INFO] Success to update lastmod for $_count post(s)."
+  fi
+}
+
+
+main
diff --git a/_scripts/sh/sync_monitor.sh b/_scripts/sh/sync_monitor.sh
index e2bfca0..5655e0f 100644
--- a/_scripts/sh/sync_monitor.sh
+++ b/_scripts/sh/sync_monitor.sh
@@ -33,6 +33,6 @@ if [[ -f "$1" ]]; then
 fi
 
 if [[ $related_dir == "_posts" ]]; then
-  python $3/_scripts/py/init_all.py
-  python $3/_scripts/py/update_posts_lastmod.py -f "$dest/$(basename $1)" -t fs
+  bash $3/_scripts/sh/create_pages.sh
+  bash $3/_scripts/sh/dump_lastmod.sh
 fi
diff --git a/tools/build.sh b/tools/build.sh
index 1f0a1c0..3381d5a 100755
--- a/tools/build.sh
+++ b/tools/build.sh
@@ -17,7 +17,7 @@ CONTAINER=${WORK_DIR}/.container
 DEST=${WORK_DIR}/_site
 
 
-help() {
+_help() {
   echo "Usage:"
   echo
   echo "   bash build.sh [options]"
@@ -29,7 +29,7 @@ help() {
 }
 
 
-init() {
+_init() {
   cd $WORK_DIR
 
   if [[ -d $CONTAINER ]]; then
@@ -40,18 +40,19 @@ init() {
     jekyll clean
   fi
 
-  temp=$(mktemp -d)
-  cp -r * $temp
-  cp -r .git $temp
-  mv $temp $CONTAINER
+  local _temp=$(mktemp -d)
+  cp -r * $_temp
+  cp -r .git $_temp
+  mv $_temp $CONTAINER
 }
 
 
-build() {
+_build() {
   cd $CONTAINER
-
   echo "$ cd $(pwd)"
-  python _scripts/py/init_all.py
+
+  bash _scripts/sh/create_pages.sh
+  bash _scripts/sh/dump_lastmod.sh
 
   CMD+=" -d ${DEST}"
   echo "\$ $CMD"
@@ -70,10 +71,10 @@ build() {
 }
 
 
-check_unset() {
+_check_unset() {
   if [[ -z ${1:+unset} ]]
   then
-    help
+    _help
     exit 1
   fi
 }
@@ -85,36 +86,36 @@ main() {
     opt="$1"
     case $opt in
       -b|--baseurl)
-        check_unset $2
+        _check_unset $2
         if [[ $2 == \/* ]]
         then
           CMD+=" -b $2"
         else
-          help
+          _help
           exit 1
         fi
         shift
         shift
         ;;
       -d|--destination)
-        check_unset $2
+        _check_unset $2
         DEST=$(realpath $2)
         shift;
         shift;
         ;;
       -h|--help)
-        help
+        _help
         exit 0
         ;;
       *) # unknown option
-        help
+        _help
         exit 1
         ;;
     esac
   done
 
-  init
-  build
+  _init
+  _build
 }
 
 main "$@"
diff --git a/tools/init.sh b/tools/init.sh
index 7db76a5..ec3d2fb 100755
--- a/tools/init.sh
+++ b/tools/init.sh
@@ -15,16 +15,26 @@ LASTMOD=false
 WORK_DIR=$(dirname $(dirname $(realpath "$0")))
 
 check_status() {
-  if [[ ! -z $(git status _posts -s) ]]; then
-    echo "Warning: Commit the changes of the directory '_posts' first."
-    git status -s | grep '_posts'
-    exit 1
-  fi
+  local _watching_dirs=(
+    "_post"
+    "_data")
+
+  for i in "${!_watching_dirs[@]}"
+  do
+    local _dir=${_watching_dirs[${i}]}
+    if [[ ! -z $(git status $_dir -s) ]]; then
+      echo "Warning: Commit the changes of the directory '$_dir' first."
+      git status -s | grep $_dir
+      exit 1
+    fi
+  done
 }
 
 
 update_files() {
-  python _scripts/py/init_all.py
+  bash _scripts/sh/create_pages.sh
+  bash _scripts/sh/dump_lastmod.sh
+
   find . | grep -E "(__pycache__|\.pyc|\.pyo$)" | xargs rm -rf
 }
 
@@ -49,8 +59,8 @@ commit() {
     TAGS=true
   fi
 
-  if [[ ! -z $(git status _posts -s) ]]; then
-    git add _posts/
+  if [[ ! -z $(git status _data -s) ]]; then
+    git add _data
     if [[ $CATEGORIES = true || $TAGS = true ]]; then
       msg+=","
     else
diff --git a/tools/run.sh b/tools/run.sh
index d75e272..339ea7e 100755
--- a/tools/run.sh
+++ b/tools/run.sh
@@ -21,7 +21,7 @@ cmd="bundle exec jekyll s"
 realtime=false
 
 
-help() {
+_help() {
   echo "Usage:"
   echo
   echo "   bash run.sh [options]"
@@ -36,7 +36,7 @@ help() {
 }
 
 
-cleanup() {
+_cleanup() {
   if [[ -d _site || -d .jekyll-cache ]]; then
     jekyll clean
   fi
@@ -46,7 +46,7 @@ cleanup() {
 }
 
 
-init() {
+_init() {
 
   if [[ -d ${WORK_DIR}/${CONTAINER} ]]; then
     rm -rf ${WORK_DIR}/${CONTAINER}
@@ -57,19 +57,19 @@ init() {
   cp -r ${WORK_DIR}/.git $temp
   mv $temp ${WORK_DIR}/${CONTAINER}
 
-  trap cleanup INT
+  trap _cleanup INT
 }
 
 
-check_unset() {
+_check_unset() {
   if [[ -z ${1:+unset} ]]; then
-    help
+    _help
     exit 1
   fi
 }
 
 
-check_command() {
+_check_command() {
   if [[ -z $(command -v $1) ]]; then
     echo "Error: command '$1' not found !"
     echo "Hint: Get '$1' on <$2>"
@@ -79,10 +79,11 @@ check_command() {
 
 
 main() {
-  init
+  _init
 
   cd ${WORK_DIR}/${CONTAINER}
-  python _scripts/py/init_all.py
+  bash _scripts/sh/create_pages.sh
+  bash _scripts/sh/dump_lastmod.sh
 
   if [[ $realtime = true ]]; then
     fswatch -0 -e "\\$CONTAINER" -e "\.git" ${WORK_DIR} | xargs -0 -I {} bash ./${SYNC_TOOL} {} $WORK_DIR . &
@@ -98,24 +99,24 @@ do
   opt="$1"
   case $opt in
     -H|--host)
-      check_unset $2
+      _check_unset $2
       cmd+=" -H $2"
       shift # past argument
       shift # past value
       ;;
     -P|--port)
-      check_unset $2
+      _check_unset $2
       cmd+=" -P $2"
       shift
       shift
       ;;
     -b|--baseurl)
-      check_unset $2
+      _check_unset $2
       if [[ $2 == \/* ]]
       then
         cmd+=" -b $2"
       else
-        help
+        _help
         exit 1
       fi
       shift
@@ -126,20 +127,21 @@ do
       shift
       ;;
     -r|--realtime)
-      check_command fswatch 'http://emcrisostomo.github.io/fswatch/'
+      _check_command fswatch 'http://emcrisostomo.github.io/fswatch/'
       realtime=true
       shift
       ;;
     -h|--help)
-      help
+      _help
       exit 0
       ;;
     *)
       # unknown option
-      help
+      _help
       exit 1
       ;;
   esac
 done
 
+
 main