diff --git a/.pre-commit-config.yaml b/.pre-commit-config.yaml
index ef9f0751..c78c1112 100644
--- a/.pre-commit-config.yaml
+++ b/.pre-commit-config.yaml
@@ -1,9 +1,10 @@
 repos:
   - repo: https://github.com/psf/black
-    rev: 21.6b0
+    rev: 21.12b0
     hooks:
       - id: black
         args: ["--target-version", "py27"]
+        additional_dependencies: ["click==7.1.2"]
   - repo: https://github.com/PyCQA/flake8
     rev: 3.9.2
     hooks:
diff --git a/dev-requirements.txt b/dev-requirements.txt
index 0645a666..0ef58b9d 100644
--- a/dev-requirements.txt
+++ b/dev-requirements.txt
@@ -3,4 +3,5 @@ pytest-cov
 sphinx>=1.1
 pre-commit==2.13.0; python_version > '3.5'
 black; python_version > '3.5' and platform_python_implementation != 'PyPy'
+click==7.1.2
 mypy; python_version > '3.5' and platform_python_implementation != 'PyPy'
diff --git a/distro.py b/distro.py
index 5d298f63..a54e54a0 100644
--- a/distro.py
+++ b/distro.py
@@ -1,3 +1,4 @@
+#!/usr/bin/env python
 # Copyright 2015,2016,2017 Nir Cohen
 #
 # Licensed under the Apache License, Version 2.0 (the "License");
@@ -85,6 +86,7 @@
 #: * Value: Normalized value.
 NORMALIZED_OS_ID = {
     "ol": "oracle",  # Oracle Linux
+    "opensuse-leap": "opensuse",  # Newer versions of OpenSuSE report as opensuse-leap
 }
 
 #: Translation table for normalizing the "Distributor ID" attribute returned by
@@ -151,7 +153,8 @@ def linux_distribution(full_distribution_name=True):
 
     * ``version``:  The result of :func:`distro.version`.
 
-    * ``codename``:  The result of :func:`distro.codename`.
+    * ``codename``:  The extra item (usually in parentheses) after the
+      os-release version number, or the result of :func:`distro.codename`.
 
     The interface of this function is compatible with the original
     :py:func:`platform.linux_distribution` function, supporting a subset of
@@ -198,8 +201,9 @@ def id():
     "fedora"        Fedora
     "sles"          SUSE Linux Enterprise Server
     "opensuse"      openSUSE
-    "amazon"        Amazon Linux
+    "amzn"          Amazon Linux
     "arch"          Arch Linux
+    "buildroot"     Buildroot
     "cloudlinux"    CloudLinux OS
     "exherbo"       Exherbo Linux
     "gentoo"        GenToo Linux
@@ -219,6 +223,8 @@ def id():
     "netbsd"        NetBSD
     "freebsd"       FreeBSD
     "midnightbsd"   MidnightBSD
+    "rocky"         Rocky Linux
+    "guix"          Guix System
     ==============  =========================================
 
     If you have a need to get distros for reliable IDs added into this set,
@@ -313,6 +319,10 @@ def version(pretty=False, best=False):
     sources in a fixed priority order does not always yield the most precise
     version (e.g. for Debian 8.2, or CentOS 7.1).
 
+    Some other distributions may not provide this kind of information. In these
+    cases, an empty string would be returned. This behavior can be observed
+    with rolling releases distributions (e.g. Arch Linux).
+
     The *best* parameter can be used to control the approach for the returned
     version:
 
@@ -723,10 +733,6 @@ def __init__(
         * :py:exc:`IOError`: Some I/O issue with an os-release file or distro
           release file.
 
-        * :py:exc:`subprocess.CalledProcessError`: The lsb_release command had
-          some issue (other than not being available in the program execution
-          path).
-
         * :py:exc:`UnicodeError`: A data source has unexpected characters or
           uses an unexpected encoding.
         """
@@ -784,7 +790,7 @@ def linux_distribution(self, full_distribution_name=True):
         return (
             self.name() if full_distribution_name else self.id(),
             self.version(),
-            self.codename(),
+            self._os_release_info.get("release_codename") or self.codename(),
         )
 
     def id(self):
@@ -860,6 +866,13 @@ def version(self, pretty=False, best=False):
             ).get("version_id", ""),
             self.uname_attr("release"),
         ]
+        if self.id() == "debian" or "debian" in self.like().split():
+            # On Debian-like, add debian_version file content to candidates list.
+            try:
+                with open(os.path.join(self.etc_dir, "debian_version")) as fp:
+                    versions.append(fp.readline().rstrip())
+            except IOError:
+                pass
         version = ""
         if best:
             # This algorithm uses the last version in priority order that has
@@ -1102,12 +1115,17 @@ def _parse_os_release_content(lines):
             # stripped, etc.), so the tokens are now either:
             # * variable assignments: var=value
             # * commands or their arguments (not allowed in os-release)
+            # Ignore any tokens that are not variable assignments
             if "=" in token:
                 k, v = token.split("=", 1)
                 props[k.lower()] = v
-            else:
-                # Ignore any tokens that are not variable assignments
-                pass
+
+        if "version" in props:
+            # extract release codename (if any) from version attribute
+            match = re.search(r"\((\D+)\)|,\s*(\D+)", props["version"])
+            if match:
+                release_codename = match.group(1) or match.group(2)
+                props["codename"] = props["release_codename"] = release_codename
 
         if "version_codename" in props:
             # os-release added a version_codename field.  Use that in
@@ -1118,16 +1136,6 @@ def _parse_os_release_content(lines):
         elif "ubuntu_codename" in props:
             # Same as above but a non-standard field name used on older Ubuntus
             props["codename"] = props["ubuntu_codename"]
-        elif "version" in props:
-            # If there is no version_codename, parse it from the version
-            match = re.search(r"(\(\D+\))|,(\s+)?\D+", props["version"])
-            if match:
-                codename = match.group()
-                codename = codename.strip("()")
-                codename = codename.strip(",")
-                codename = codename.strip()
-                # codename appears within paranthese.
-                props["codename"] = codename
 
         return props
 
@@ -1276,6 +1284,7 @@ def _distro_release_info(self):
                     "manjaro-release",
                     "oracle-release",
                     "redhat-release",
+                    "rocky-release",
                     "sl-release",
                     "slackware-version",
                 ]
diff --git a/tests/resources/distros/buildroot/etc/os-release b/tests/resources/distros/buildroot/etc/os-release
new file mode 100644
index 00000000..3aeb5317
--- /dev/null
+++ b/tests/resources/distros/buildroot/etc/os-release
@@ -0,0 +1,5 @@
+NAME=Buildroot
+VERSION=2022.02
+ID=buildroot
+VERSION_ID=2022.02
+PRETTY_NAME="Buildroot 2022.02"
diff --git a/tests/resources/distros/debian10/bin/lsb_release b/tests/resources/distros/debian10/bin/lsb_release
new file mode 100644
index 00000000..7d269dcc
--- /dev/null
+++ b/tests/resources/distros/debian10/bin/lsb_release
@@ -0,0 +1,21 @@
+#!/bin/bash
+#
+# lsb_release command for testing the ld module.
+# Only the -a option is supported.
+#
+# This version of the lsb_release command works without a corresponding
+# etc/lsb-release file.
+#
+
+if [[ "$@" != "-a" ]]; then
+  echo "Usage: lsb_release -a"
+  exit 2
+fi
+
+echo "No LSB modules are available."
+echo "Distributor ID:	Debian"
+echo "Description:	Debian GNU/Linux 10 (buster)"
+echo "Release:	10"
+echo "Codename:	buster"
+
+exit 0
diff --git a/tests/resources/distros/debian10/etc/debian_version b/tests/resources/distros/debian10/etc/debian_version
new file mode 100644
index 00000000..7f0c091e
--- /dev/null
+++ b/tests/resources/distros/debian10/etc/debian_version
@@ -0,0 +1 @@
+10.11
diff --git a/tests/resources/distros/debian10/etc/os-release b/tests/resources/distros/debian10/etc/os-release
new file mode 100644
index 00000000..9b5419df
--- /dev/null
+++ b/tests/resources/distros/debian10/etc/os-release
@@ -0,0 +1,9 @@
+PRETTY_NAME="Debian GNU/Linux 10 (buster)"
+NAME="Debian GNU/Linux"
+VERSION_ID="10"
+VERSION="10 (buster)"
+VERSION_CODENAME=buster
+ID=debian
+HOME_URL="https://www.debian.org/"
+SUPPORT_URL="https://www.debian.org/support"
+BUG_REPORT_URL="https://bugs.debian.org/"
diff --git a/tests/resources/distros/guix/etc/os-release b/tests/resources/distros/guix/etc/os-release
new file mode 100644
index 00000000..8aa5b73d
--- /dev/null
+++ b/tests/resources/distros/guix/etc/os-release
@@ -0,0 +1,8 @@
+NAME="Guix System"
+ID=guix
+PRETTY_NAME="Guix System"
+LOGO=guix-icon
+HOME_URL="https://guix.gnu.org"
+DOCUMENTATION_URL="https://guix.gnu.org/en/manual"
+SUPPORT_URL="https://guix.gnu.org/en/help"
+BUG_REPORT_URL="https://lists.gnu.org/mailman/listinfo/bug-guix"
diff --git a/tests/resources/distros/opensuse15/etc/os-release b/tests/resources/distros/opensuse15/etc/os-release
new file mode 100644
index 00000000..1494bc55
--- /dev/null
+++ b/tests/resources/distros/opensuse15/etc/os-release
@@ -0,0 +1,10 @@
+NAME="openSUSE Leap"
+VERSION="15.2"
+ID="opensuse-leap"
+ID_LIKE="suse opensuse"
+VERSION_ID="15.2"
+PRETTY_NAME="openSUSE Leap 15.2"
+ANSI_COLOR="0;32"
+CPE_NAME="cpe:/o:opensuse:leap:15.2"
+BUG_REPORT_URL="https://bugs.opensuse.org"
+HOME_URL="https://www.opensuse.org/"
diff --git a/tests/resources/distros/rocky/etc/centos-release b/tests/resources/distros/rocky/etc/centos-release
new file mode 120000
index 00000000..780b78a5
--- /dev/null
+++ b/tests/resources/distros/rocky/etc/centos-release
@@ -0,0 +1 @@
+rocky-release
\ No newline at end of file
diff --git a/tests/resources/distros/rocky/etc/os-release b/tests/resources/distros/rocky/etc/os-release
new file mode 120000
index 00000000..c4c75b41
--- /dev/null
+++ b/tests/resources/distros/rocky/etc/os-release
@@ -0,0 +1 @@
+../usr/lib/os-release
\ No newline at end of file
diff --git a/tests/resources/distros/rocky/etc/redhat-release b/tests/resources/distros/rocky/etc/redhat-release
new file mode 120000
index 00000000..780b78a5
--- /dev/null
+++ b/tests/resources/distros/rocky/etc/redhat-release
@@ -0,0 +1 @@
+rocky-release
\ No newline at end of file
diff --git a/tests/resources/distros/rocky/etc/rocky-release b/tests/resources/distros/rocky/etc/rocky-release
new file mode 100644
index 00000000..b7323215
--- /dev/null
+++ b/tests/resources/distros/rocky/etc/rocky-release
@@ -0,0 +1 @@
+Rocky Linux release 8.4 (Green Obsidian)
diff --git a/tests/resources/distros/rocky/etc/rocky-release-upstream b/tests/resources/distros/rocky/etc/rocky-release-upstream
new file mode 100644
index 00000000..5d7b2828
--- /dev/null
+++ b/tests/resources/distros/rocky/etc/rocky-release-upstream
@@ -0,0 +1 @@
+Derived from Red Hat Enterprise Linux 8.4
diff --git a/tests/resources/distros/rocky/etc/system-release b/tests/resources/distros/rocky/etc/system-release
new file mode 120000
index 00000000..780b78a5
--- /dev/null
+++ b/tests/resources/distros/rocky/etc/system-release
@@ -0,0 +1 @@
+rocky-release
\ No newline at end of file
diff --git a/tests/resources/distros/rocky/etc/system-release-cpe b/tests/resources/distros/rocky/etc/system-release-cpe
new file mode 100644
index 00000000..741db580
--- /dev/null
+++ b/tests/resources/distros/rocky/etc/system-release-cpe
@@ -0,0 +1 @@
+cpe:/o:rocky:rocky:8.4:GA
diff --git a/tests/resources/distros/rocky/usr/lib/os-release b/tests/resources/distros/rocky/usr/lib/os-release
new file mode 100644
index 00000000..f753b059
--- /dev/null
+++ b/tests/resources/distros/rocky/usr/lib/os-release
@@ -0,0 +1,13 @@
+NAME="Rocky Linux"
+VERSION="8.4 (Green Obsidian)"
+ID="rocky"
+ID_LIKE="rhel centos fedora"
+VERSION_ID="8.4"
+PLATFORM_ID="platform:el8"
+PRETTY_NAME="Rocky Linux 8.4 (Green Obsidian)"
+ANSI_COLOR="0;32"
+CPE_NAME="cpe:/o:rocky:rocky:8.4:GA"
+HOME_URL="https://rockylinux.org/"
+BUG_REPORT_URL="https://bugs.rockylinux.org/"
+ROCKY_SUPPORT_PRODUCT="Rocky Linux"
+ROCKY_SUPPORT_PRODUCT_VERSION="8"
diff --git a/tests/test_distro.py b/tests/test_distro.py
index 212357be..9ae43b6f 100644
--- a/tests/test_distro.py
+++ b/tests/test_distro.py
@@ -139,11 +139,10 @@ def _setup_for_distro(self, distro_root):
 class TestOSRelease:
     def setup_method(self, test_method):
         dist = test_method.__name__.split("_")[1]
-        os_release = os.path.join(DISTROS_DIR, dist, "etc", "os-release")
         self.distro = distro.LinuxDistribution(
             include_lsb=False,
-            os_release_file=os_release,
             distro_release_file="path-to-non-existing-file",
+            root_dir=os.path.join(DISTROS_DIR, dist),
         )
 
     def _test_outcome(self, outcome):
@@ -164,6 +163,17 @@ def test_arch_os_release(self):
         }
         self._test_outcome(desired_outcome)
 
+    def test_buildroot_os_release(self):
+        desired_outcome = {
+            "id": "buildroot",
+            "name": "Buildroot",
+            "pretty_name": "Buildroot 2022.02",
+            "version": "2022.02",
+            "pretty_version": "2022.02",
+            "best_version": "2022.02",
+        }
+        self._test_outcome(desired_outcome)
+
     def test_kali_os_release(self):
         desired_outcome = {
             "id": "kali",
@@ -207,11 +217,23 @@ def test_debian8_os_release(self):
             "pretty_name": "Debian GNU/Linux 8 (jessie)",
             "version": "8",
             "pretty_version": "8 (jessie)",
-            "best_version": "8",
+            "best_version": "8.2",
             "codename": "jessie",
         }
         self._test_outcome(desired_outcome)
 
+    def test_debian10_os_release(self):
+        desired_outcome = {
+            "id": "debian",
+            "name": "Debian GNU/Linux",
+            "pretty_name": "Debian GNU/Linux 10 (buster)",
+            "version": "10",
+            "pretty_version": "10 (buster)",
+            "best_version": "10.11",
+            "codename": "buster",
+        }
+        self._test_outcome(desired_outcome)
+
     def test_fedora19_os_release(self):
         desired_outcome = {
             "id": "fedora",
@@ -252,6 +274,14 @@ def test_fedora30_os_release(self):
         }
         self._test_outcome(desired_outcome)
 
+    def test_guix_os_release(self):
+        desired_outcome = {
+            "id": "guix",
+            "name": "Guix System",
+            "pretty_name": "Guix System",
+        }
+        self._test_outcome(desired_outcome)
+
     def test_kvmibm1_os_release(self):
         desired_outcome = {
             "id": "kvmibm",
@@ -309,6 +339,18 @@ def test_opensuse42_os_release(self):
         }
         self._test_outcome(desired_outcome)
 
+    def test_opensuse15_os_release(self):
+        desired_outcome = {
+            "id": "opensuse",
+            "name": "openSUSE Leap",
+            "pretty_name": "openSUSE Leap 15.2",
+            "version": "15.2",
+            "pretty_version": "15.2",
+            "best_version": "15.2",
+            "like": "suse opensuse",
+        }
+        self._test_outcome(desired_outcome)
+
     def test_raspbian7_os_release(self):
         desired_outcome = {
             "id": "raspbian",
@@ -316,7 +358,7 @@ def test_raspbian7_os_release(self):
             "pretty_name": "Raspbian GNU/Linux 7 (wheezy)",
             "version": "7",
             "pretty_version": "7 (wheezy)",
-            "best_version": "7",
+            "best_version": "7.1",
             "like": "debian",
             "codename": "wheezy",
         }
@@ -329,7 +371,7 @@ def test_raspbian8_os_release(self):
             "pretty_name": "Raspbian GNU/Linux 8 (jessie)",
             "version": "8",
             "pretty_version": "8 (jessie)",
-            "best_version": "8",
+            "best_version": "8.0",
             "like": "debian",
             "codename": "jessie",
         }
@@ -348,6 +390,19 @@ def test_rhel7_os_release(self):
         }
         self._test_outcome(desired_outcome)
 
+    def test_rocky_os_release(self):
+        desired_outcome = {
+            "id": "rocky",
+            "name": "Rocky Linux",
+            "pretty_name": "Rocky Linux 8.4 (Green Obsidian)",
+            "version": "8.4",
+            "pretty_version": "8.4 (Green Obsidian)",
+            "best_version": "8.4",
+            "like": "rhel centos fedora",
+            "codename": "Green Obsidian",
+        }
+        self._test_outcome(desired_outcome)
+
     def test_slackware14_os_release(self):
         desired_outcome = {
             "id": "slackware",
@@ -480,7 +535,6 @@ def setup_method(self, test_method):
         dist = test_method.__name__.split("_")[1]
         self._setup_for_distro(os.path.join(DISTROS_DIR, dist))
         self.distro = distro.LinuxDistribution(
-            include_lsb=True,
             os_release_file="path-to-non-existing-file",
             distro_release_file="path-to-non-existing-file",
         )
@@ -586,7 +640,6 @@ def test_ubuntu14normal_lsb_release(self):
         self._setup_for_distro(os.path.join(TESTDISTROS, "lsb", "ubuntu14_normal"))
 
         self.distro = distro.LinuxDistribution(
-            include_lsb=True,
             os_release_file="path-to-non-existing-file",
             distro_release_file="path-to-non-existing-file",
         )
@@ -606,7 +659,6 @@ def test_ubuntu14nomodules_lsb_release(self):
         self._setup_for_distro(os.path.join(TESTDISTROS, "lsb", "ubuntu14_nomodules"))
 
         self.distro = distro.LinuxDistribution(
-            include_lsb=True,
             os_release_file="path-to-non-existing-file",
             distro_release_file="path-to-non-existing-file",
         )
@@ -628,7 +680,6 @@ def test_trailingblanks_lsb_release(self):
         )
 
         self.distro = distro.LinuxDistribution(
-            include_lsb=True,
             os_release_file="path-to-non-existing-file",
             distro_release_file="path-to-non-existing-file",
         )
@@ -651,7 +702,6 @@ def test_lsb_release_error_level(self, errnum):
         )
 
         lsb_release_info = distro.LinuxDistribution(
-            include_lsb=True,
             os_release_file="path-to-non-existing-file",
             distro_release_file="path-to-non-existing-file",
         )._lsb_release_info
@@ -1049,7 +1099,6 @@ class TestOverall(DistroTestCase):
     TODO: This class should have testcases for all distros that are claimed
     to be reliably maintained w.r.t. to their ID (see `id()`). Testcases for
     the following distros are still missing:
-      * `amazon` - Amazon Linux
       * `gentoo` - GenToo Linux
       * `ibm_powerkvm` - IBM PowerKVM
       * `parallels` - Parallels
@@ -1178,6 +1227,20 @@ def test_debian8_release(self):
         self._test_outcome(desired_outcome)
         self._test_non_existing_release_file()
 
+    def test_debian10_release(self):
+        desired_outcome = {
+            "id": "debian",
+            "name": "Debian GNU/Linux",
+            "pretty_name": "Debian GNU/Linux 10 (buster)",
+            "version": "10",
+            "pretty_version": "10 (buster)",
+            "best_version": "10.11",
+            "codename": "buster",
+            "major_version": "10",
+        }
+        self._test_outcome(desired_outcome)
+        self._test_non_existing_release_file()
+
     def test_exherbo_release(self):
         desired_outcome = {
             "id": "exherbo",
@@ -1354,6 +1417,20 @@ def test_opensuse42_release(self):
         }
         self._test_release_file_info("SuSE-release", desired_info)
 
+    def test_opensuse15_release(self):
+        desired_outcome = {
+            "id": "opensuse",
+            "name": "openSUSE Leap",
+            "pretty_name": "openSUSE Leap 15.2",
+            "version": "15.2",
+            "pretty_version": "15.2",
+            "best_version": "15.2",
+            "like": "suse opensuse",
+            "major_version": "15",
+            "minor_version": "2",
+        }
+        self._test_outcome(desired_outcome)
+
     def test_oracle7_release(self):
         desired_outcome = {
             "id": "oracle",
@@ -1382,7 +1459,7 @@ def test_raspbian7_release(self):
             "pretty_name": "Raspbian GNU/Linux 7 (wheezy)",
             "version": "7",
             "pretty_version": "7 (wheezy)",
-            "best_version": "7",
+            "best_version": "7.1",
             "like": "debian",
             "codename": "wheezy",
             "major_version": "7",
@@ -1397,7 +1474,7 @@ def test_raspbian8_release(self):
             "pretty_name": "Raspbian GNU/Linux 8 (jessie)",
             "version": "8",
             "pretty_version": "8 (jessie)",
-            "best_version": "8",
+            "best_version": "8.0",
             "like": "debian",
             "codename": "jessie",
             "major_version": "8",
@@ -1472,6 +1549,29 @@ def test_rhel7_release(self):
         }
         self._test_release_file_info("redhat-release", desired_info)
 
+    def test_rocky_release(self):
+        desired_outcome = {
+            "id": "rocky",
+            "name": "Rocky Linux",
+            "pretty_name": "Rocky Linux 8.4 (Green Obsidian)",
+            "version": "8.4",
+            "pretty_version": "8.4 (Green Obsidian)",
+            "best_version": "8.4",
+            "like": "rhel centos fedora",
+            "codename": "Green Obsidian",
+            "major_version": "8",
+            "minor_version": "4",
+        }
+        self._test_outcome(desired_outcome)
+
+        desired_info = {
+            "id": "centos",
+            "name": "Rocky Linux",
+            "version_id": "8.4",
+            "codename": "Green Obsidian",
+        }
+        self._test_release_file_info("centos-release", desired_info)
+
     def test_slackware14_release(self):
         desired_outcome = {
             "id": "slackware",
@@ -1772,6 +1872,9 @@ def setup_method(self, test_method):
         self.ubuntu14_os_release = os.path.join(
             DISTROS_DIR, "ubuntu14", "etc", "os-release"
         )
+        self.fedora30_os_release = os.path.join(
+            DISTROS_DIR, "fedora30", "etc", "os-release"
+        )
 
     def test_info(self):
         _distro = distro.LinuxDistribution(
@@ -1845,6 +1948,12 @@ def test_linux_distribution(self):
         assert i == ("Ubuntu", "14.04", "Trusty Tahr")
 
     def test_linux_distribution_full_false(self):
+        _distro = distro.LinuxDistribution(
+            include_lsb=False, os_release_file=self.fedora30_os_release
+        )
+        i = _distro.linux_distribution()
+        assert i == ("Fedora", "30", "Thirty")
+
         _distro = distro.LinuxDistribution(
             include_lsb=False, os_release_file=self.ubuntu14_os_release
         )
diff --git a/tox.ini b/tox.ini
index fed6d5e4..9aec2cf4 100644
--- a/tox.ini
+++ b/tox.ini
@@ -21,7 +21,7 @@ skip_missing_interpreters = true
 deps =
     pytest
     pytest-cov
-commands = pytest --cov-report term-missing --cov distro
+commands = pytest --cov-report term-missing --cov distro {posargs}
 
 [testenv:lint]
 deps = pre-commit