Ubuntu 19.10にPython2をインストール（OS標準）

# はじめに

Ubuntu 19.10にPython2をインストール

## サポート

[EoanErmine/ReleaseNotes - Ubuntu Wiki](https://wiki.ubuntu.com/EoanErmine/ReleaseNotes)より、2020-07でOSはEOLになる。
それ以降に報告された脆弱性や不具合への対応は実施されない可能性がある。

## LOG

### インストール

```shell-session
# cat /etc/os-release
NAME="Ubuntu"
VERSION="19.10 (Eoan Ermine)"
ID=ubuntu
ID_LIKE=debian
PRETTY_NAME="Ubuntu 19.10"
VERSION_ID="19.10"
HOME_URL="https://www.ubuntu.com/"
SUPPORT_URL="https://help.ubuntu.com/"
BUG_REPORT_URL="https://bugs.launchpad.net/ubuntu/"
PRIVACY_POLICY_URL="https://www.ubuntu.com/legal/terms-and-policies/privacy-policy"
VERSION_CODENAME=eoan
UBUNTU_CODENAME=eoan

# apt update; apt install -y python
... 略
```

### 各種確認

```shell-session
# which python{,2}
/usr/bin/python
/usr/bin/python2

# ll /usr/bin/python*
lrwxrwxrwx. 1 root root       7 Oct 10 11:32 /usr/bin/python -> python2*
lrwxrwxrwx. 1 root root       9 Oct 10 11:32 /usr/bin/python2 -> python2.7*
-rwxr-xr-x. 1 root root 3719240 Oct 10 10:26 /usr/bin/python2.7*

# python -V
Python 2.7.17rc1

# apt show python
Package: python
Version: 2.7.17-1
Priority: optional
Section: universe/python
Source: python-defaults
Origin: Ubuntu
Maintainer: Ubuntu Developers <ubuntu-devel-discuss@lists.ubuntu.com>
Original-Maintainer: Matthias Klose <doko@debian.org>
Bugs: https://bugs.launchpad.net/ubuntu/+filebug
Installed-Size: 69.6 kB
Provides: python-ctypes, python-email, python-importlib, python-profiler, python-wsgiref
Pre-Depends: python-minimal (= 2.7.17-1)
Depends: python2.7 (>= 2.7.17~rc1-1~), libpython-stdlib (= 2.7.17-1), python2 (= 2.7.17-1)
Suggests: python-doc (= 2.7.17-1), python-tk (>= 2.7.17~rc1-1~)
Conflicts: python-central (<< 0.5.5)
Breaks: update-manager-core (<< 0.200.5-2)
Replaces: python-dev (<< 2.6.5-2)
Homepage: https://www.python.org/
Task: xubuntu-desktop, ubuntustudio-desktop-core, ubuntustudio-desktop, ubuntukylin-desktop, ubuntu-mate-core, ubuntu-mate-desktop
Cnf-Extra-Commands: python
Cnf-Priority-Bonus: 3
Download-Size: 7836 B
APT-Manual-Installed: yes
APT-Sources: http://archive.ubuntu.com/ubuntu eoan/universe amd64 Packages
Description: interactive high-level object-oriented language (Python2 version)
```

### インストールその2

```shell-session
# cat /etc/os-release
NAME="Ubuntu"
VERSION="19.10 (Eoan Ermine)"
ID=ubuntu
ID_LIKE=debian
PRETTY_NAME="Ubuntu 19.10"
VERSION_ID="19.10"
HOME_URL="https://www.ubuntu.com/"
SUPPORT_URL="https://help.ubuntu.com/"
BUG_REPORT_URL="https://bugs.launchpad.net/ubuntu/"
PRIVACY_POLICY_URL="https://www.ubuntu.com/legal/terms-and-policies/privacy-policy"
VERSION_CODENAME=eoan
UBUNTU_CODENAME=eoan

# apt update; apt install -y python2
... 略
```

### 各種確認

```shell-session
# which python{,2}
/usr/bin/python2

# ll /usr/bin/python*
lrwxrwxrwx. 1 root root       9 Oct 10 11:32 /usr/bin/python2 -> python2.7*
-rwxr-xr-x. 1 root root 3719240 Oct 10 10:26 /usr/bin/python2.7*

# python2 -V
Python 2.7.17rc1

# apt show python2
Package: python2
Version: 2.7.17-1
Priority: optional
Section: universe/python
Source: python-defaults
Origin: Ubuntu
Maintainer: Ubuntu Developers <ubuntu-devel-discuss@lists.ubuntu.com>
Original-Maintainer: Matthias Klose <doko@debian.org>
Bugs: https://bugs.launchpad.net/ubuntu/+filebug
Installed-Size: 139 kB
Provides: python-ctypes, python-email, python-importlib, python-profiler, python-wsgiref
Pre-Depends: python2-minimal (= 2.7.17-1)
Depends: python2.7 (>= 2.7.17~rc1-1~), libpython2-stdlib (= 2.7.17-1)
Suggests: python2-doc (= 2.7.17-1), python-tk (>= 2.7.17~rc1-1~)
Conflicts: python-central (<< 0.5.5)
Breaks: python (<< 2.7.15-2), update-manager-core (<< 0.200.5-2)
Replaces: python (<< 2.7.15-2), python-dev (<< 2.6.5-2)
Homepage: https://www.python.org/
Task: xubuntu-desktop, ubuntustudio-desktop-core, ubuntustudio-desktop, ubuntukylin-desktop, ubuntu-mate-core, ubuntu-mate-desktop
Cnf-Extra-Commands: python2
Cnf-Priority-Bonus: 3
Download-Size: 26.5 kB
APT-Manual-Installed: yes
APT-Sources: http://archive.ubuntu.com/ubuntu eoan/universe amd64 Packages
Description: interactive high-level object-oriented language (Python2 version)
```