diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index dd83887..7e41db4 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -50,3 +50,6 @@ jobs:
         run: |
           python setup.py bdist_wheel
           pip install --no-cache-dir dist/legunto-*.whl
+
+      - name: Unit test
+        run: pytest
diff --git a/.gitignore b/.gitignore
index 25d4cad..77aac90 100644
--- a/.gitignore
+++ b/.gitignore
@@ -1,5 +1,15 @@
+# Legunto
+scribunto.json
+scribunto.lock
+lua/
+
+
+# Node
 node_modules/
 
+
+# Python
+
 # Byte-compiled / optimized / DLL files
 __pycache__/
 *.py[cod]
diff --git a/.prettierignore b/.prettierignore
index 21d0b89..c627289 100644
--- a/.prettierignore
+++ b/.prettierignore
@@ -1 +1,4 @@
 .venv/
+scribunto.json
+scribunto.lock
+lua/
diff --git a/README.md b/README.md
index 63e4439..931c856 100644
--- a/README.md
+++ b/README.md
@@ -1,3 +1,8 @@
 # legunto
 
-Fetch MediaWiki Scribunto modules from wikis
+Fetch MediaWiki Scribunto modules from wikis and save as files
+
+## Limitations
+
+- Wiki pages can have a slash(`/`) in their name, but filenames in unix can't. Slashes is converted
+  to hyphens(`-`) on saving.
diff --git a/legunto b/legunto
deleted file mode 100755
index 07728b6..0000000
--- a/legunto
+++ /dev/null
@@ -1,8 +0,0 @@
-#!/usr/bin/env python
-
-def main():
-    print("Hello legunto!")
-
-
-if __name__ == '__main__':
-    main()
diff --git a/setup.py b/setup.py
index 356fdef..8efb9a7 100644
--- a/setup.py
+++ b/setup.py
@@ -6,10 +6,18 @@
 setuptools.setup(
     name="legunto",
     version="0.0.1",
-    scripts=["legunto"],
     description="Fetch MediaWiki Scribunto modules from wikis",
     long_description=long_description,
     long_description_content_type="text/markdown",
-    packages=setuptools.find_packages(),
+
+    packages=[
+        'legunto',
+        'scribunto'
+    ],
     install_requires=["mwclient"],
+    package_dir={'': 'src'},
+
+    entry_points={
+        'console_scripts': ['legunto = legunto:console_main'],
+    }
 )
diff --git a/src/legunto/__init__.py b/src/legunto/__init__.py
new file mode 100644
index 0000000..c73fe2c
--- /dev/null
+++ b/src/legunto/__init__.py
@@ -0,0 +1,132 @@
+from scribunto import search_dependencies, rewrite_requires
+from urllib.parse import urlparse
+import json
+import logging
+import mwclient
+import os
+import pathlib
+import sys
+
+
+def print_help_massage() -> None:
+    print("""
+Usage:  legunto COMMAND
+
+Commands:
+  install     fetch lua modules based on 'scribunto.json'
+""")
+
+
+def get_interwiki_map() -> hash:
+    site = mwclient.Site('meta.wikimedia.org')
+    result = site.api('query', meta='siteinfo', siprop='interwikimap')
+    result = result["query"]["interwikimap"]
+
+    iw_map = {}
+    for wiki in result:
+        iw_map[wiki['prefix']] = wiki['url']
+
+    return iw_map
+
+
+def fetch_module(url: str, module_name: str) -> hash:
+    if not module_name.startswith('Module:'):
+        module_name = 'Module:'+module_name
+
+    module = {}
+
+    url = urlparse(url)
+    print(f'Fetching "{module_name}" from {url.netloc} ...', end='')
+    site = mwclient.Site(url.netloc, scheme=url.scheme)
+
+    result = site.api('query', titles=module_name, prop='info', utf8="1")
+    result = list(result['query']['pages'].values())[0]
+    module['pageid'] = result['pageid']
+    module['revid'] = result['lastrevid']
+    module['title'] = result['title']
+    module['text'] = site.pages[module_name].text()
+    print(' Done')
+
+    return module
+
+
+def to_filename(name: str) -> str:
+    return name.split(':')[1] \
+        .replace('/', '-')
+
+
+def install_dependencies() -> None:
+    SCRIBUNTO_FILE_PATH = os.getcwd()+"/scribunto.json"
+    if not os.path.exists(SCRIBUNTO_FILE_PATH):
+        logging.error("Can't find 'scribunto.json' file in this directory")
+
+    dependencies = json.loads(open(SCRIBUNTO_FILE_PATH, "r").read())[
+        "dependencies"]
+
+    interwiki = get_interwiki_map()
+
+    lock = {
+        'modules': {}
+    }
+
+    deps_to_add = dependencies
+
+    print(f'{len(deps_to_add)} dependency(s) found')
+
+    while deps_to_add:
+        dep = deps_to_add.pop()
+        if dep in lock['modules']:
+            continue
+
+        wiki, page = dep.split("/", 1)
+        if wiki[0] == "@":
+            wiki = wiki[1:]
+
+        if wiki not in interwiki:
+            logging.warning(f"'{wiki}' is not a valid interwiki prefix")
+            logging.warning(f"skip '{dep}'...")
+            continue
+
+        # TODO read lock file and compare revids to skip fetching
+
+        module = fetch_module(interwiki[wiki], page)
+        lock['modules'][dep] = {
+            'pageid': module['pageid'],
+            'revid': module['revid'],
+            'title': module['title'],
+        }
+        indirect_deps = search_dependencies(module['text'], prefix=wiki)
+        if indirect_deps:
+            lock['modules'][dep]['dependencies'] = indirect_deps
+
+        path = os.getcwd()+"/lua/"+wiki
+        if not os.path.exists(path):
+            pathlib.Path(path).mkdir(parents=True)
+
+        f = open(path+"/" + to_filename(module['title']), "w")
+        f.write(rewrite_requires(module['text'], prefix=wiki))
+        f.close()
+
+        deps_to_add += indirect_deps
+
+    f = open(os.getcwd()+"/scribunto.lock", "w")
+    f.write(json.dumps(lock, indent=2))
+    f.close()
+
+
+def console_main() -> None:
+    if len(sys.argv) == 1 or \
+            (len(sys.argv) == 2 and sys.argv[1] in ['--help', 'help']):
+        print_help_massage()
+        return
+    elif len(sys.argv) == 2 and sys.argv[1] == 'install':
+        install_dependencies()
+    else:
+        logging.error(
+            f"legunto: '{sys.argv[1]}' is not a legunto command."
+            "See 'legunto --help'")
+
+
+__all__ = [
+    "console_main"
+]
diff --git a/src/legunto/__main__.py b/src/legunto/__main__.py
new file mode 100644
index 0000000..b46d6c9
--- /dev/null
+++ b/src/legunto/__main__.py
@@ -0,0 +1,5 @@
+import legunto
+
+
+if __name__ == '__main__':
+    raise SystemExit(legunto.console_main())
diff --git a/src/scribunto/__init__.py b/src/scribunto/__init__.py
new file mode 100644
index 0000000..5968624
--- /dev/null
+++ b/src/scribunto/__init__.py
@@ -0,0 +1,43 @@
+import re
+from typing import List
+
+
+def search_dependencies(text: str, prefix=None) -> List[str]:
+    regex = \
+        r'''(?:require|mw\.loadData)\s*\(\s*['"](?:[Mm]odule|모듈):(.+)['"]\s*'''
+
+    find = re.findall(regex, text)
+    find = list(set(find))
+    if prefix:
+        find = [
+            f"@{prefix}/{name}"
+            for name in find
+        ]
+
+    return find
+
+
+def rewrite_requires(text: str, prefix: str) -> str:
+    # Module:foo/bar -> Module:foo-bar
+    regex = \
+        r'''(?:require|mw\.loadData)\s*\(\s*['"](?:[Mm]odule|모듈):.+['"]\s*'''
+
+    module_names = re.findall(regex, text)
+    for name in module_names:
+        text = text.replace(name, name.replace("/", "-"))
+
+    # Module:foo -> Module:@en/foo
+    regex = (
+        r"""((?:require|mw\.loadData)\s*\(\s*['"](?:[Mm]odule|모듈):)"""
+        r"""(.+)(['"]\s*)"""
+    )
+
+    text = re.sub(regex, fr'\1@{prefix}/\2\3', text)
+
+    return text
+
+
+__all__ = [
+    'search_dependencies',
+    'rewrite_requires',
+]
diff --git a/test/legunto_test.py b/test/legunto_test.py
new file mode 100644
index 0000000..1a7eecd
--- /dev/null
+++ b/test/legunto_test.py
@@ -0,0 +1,15 @@
+import legunto
+
+
+def test_to_filename():
+    assert legunto.to_filename('Module:foo') == \
+        'foo'
+
+    assert legunto.to_filename('Module:foo bar') == \
+        'foo bar'
+
+    assert legunto.to_filename('Module:foo/bar') == \
+        'foo-bar'
+
+    assert legunto.to_filename('모듈:foo/bar') == \
+        'foo-bar'
diff --git a/test/scribunto_test.py b/test/scribunto_test.py
new file mode 100644
index 0000000..3ba5103
--- /dev/null
+++ b/test/scribunto_test.py
@@ -0,0 +1,61 @@
+import scribunto
+
+
+def test_search_dependencies() -> None:
+    text = '''
+local mHatnote = require('Module:Hatnote')
+local mHatList = require('Module:Hatnote list')
+local libraryUtil = require('libraryUtil')
+local checkType = libraryUtil.checkType
+local p = {}
+'''
+
+    expected = [
+        'Hatnote',
+        'Hatnote list',
+    ]
+    actual = scribunto.search_dependencies(text)
+
+    assert actual.sort() == expected.sort()
+
+    # with prefix
+
+    text = '''
+local mHatnote = require('Module:Hatnote')
+local mHatList = require('Module:Hatnote list')
+'''
+
+    expected = [
+        '@en/Hatnote',
+        '@en/Hatnote list',
+    ]
+    actual = scribunto.search_dependencies(text, prefix='en')
+
+    assert actual.sort() == expected.sort()
+
+
+def test_rewrite_requires() -> None:
+    text = '''
+local mHatnote = require('Module:Hatnote')
+local mHatList = require('Module:Hatnote list')
+local libraryUtil = require('libraryUtil')
+local checkType = libraryUtil.checkType
+local p = {}
+'''
+
+    expected = '''
+local mHatnote = require('Module:@en/Hatnote')
+local mHatList = require('Module:@en/Hatnote list')
+local libraryUtil = require('libraryUtil')
+local checkType = libraryUtil.checkType
+local p = {}
+'''
+    actual = scribunto.rewrite_requires(text, 'en')
+
+    assert actual == expected
+
+    text = "require('Module:Foo/bar')"
+    expected = "require('Module:@en/Foo-bar')"
+    actual = scribunto.rewrite_requires(text, 'en')
+
+    assert actual == expected