安装的python3.9 3.9在linux中未显示

Question

我按照这个链接中的步骤安装了python3.9。

1. sudo apt update
2. sudo apt install python3.9
3. python3.9
4. sudo update-alternatives --install /usr/bin/python3 python3 /usr/bin/python3.[old-version] 1
5. sudo update-alternatives --install /usr/bin/python3 python3 /usr/bin/python3.9 2
6. sudo update-alternatives --config python3

然而，它在第3点抛出了一个python3.9 not found错误。另外，我注意到了python3.9在安装时使用的第二点显示了Note, selecting 'postgresql-plpython3-9.5' for regex 'python3.9'。

完整消息是

Reading package lists... Done
Building dependency tree
Reading state information... Done
Note, selecting 'postgresql-plpython3-9.5' for regex 'python3.9'
The following packages were automatically installed and are no longer required:
  linux-aws-headers-4.4.0-1104 linux-aws-headers-4.4.0-1105 linux-aws-headers-4.4.0-1106 linux-aws-headers-4.4.0-1107 linux-aws-headers-4.4.0-1109 linux-aws-headers-4.4.0-1110 linux-aws-headers-4.4.0-1111
  linux-aws-headers-4.4.0-1112 linux-aws-headers-4.4.0-1113 linux-aws-headers-4.4.0-1114
Use 'sudo apt autoremove' to remove them.
The following NEW packages will be installed:
  postgresql-plpython3-9.5
0 upgraded, 1 newly installed, 0 to remove and 56 not upgraded.
Need to get 0 B/40.6 kB of archives.
After this operation, 166 kB of additional disk space will be used.
Selecting previously unselected package postgresql-plpython3-9.5.
(Reading database ... 362651 files and directories currently installed.)
Preparing to unpack .../postgresql-plpython3-9.5_9.5.25-0ubuntu0.16.04.1_amd64.deb ...
Unpacking postgresql-plpython3-9.5 (9.5.25-0ubuntu0.16.04.1) ...
Processing triggers for postgresql-common (173ubuntu0.3) ...
Building PostgreSQL dictionaries from installed myspell/hunspell packages...
Removing obsolete dictionary files:
Setting up postgresql-plpython3-9.5 (9.5.25-0ubuntu0.16.04.1) ...

为什么要设置PostgreSQLplpython3-9.5，我怎样才能阻止它这样做呢？

Answer 1

问题是：

死蛇ppa不再适用于Ubuntu。这就是你不能安装python3.9的原因。参见这问题。您必须从源代码编译或将您的服务器升级到受支持的Ubuntu版本。

解决方案:自己构建

如果您无法升级您的系统，您可以使用碧昂夫安装任何给定的python版本，如下所述。为此，需要为python >= 3.8安装一个新版本的openssl

# install dependencies
apt update
apt install -y build-essential zlib1g-dev libncurses5-dev libgdbm-dev libnss3-dev libssl-dev libsqlite3-dev libreadline-dev libffi-dev curl libbz2-dev liblzma-dev git

# download and compile openssl
curl -L https://www.openssl.org/source/openssl-1.1.1q.tar.gz | (cd /usr/src; tar xz)
cd /usr/src/openssl-1.1.1q && ./config --prefix=/usr/local && make -j4 && make install

# download and configure pyenv
curl -L https://github.com/pyenv/pyenv-installer/raw/master/bin/pyenv-installer | bash

echo >> ~/.bashrc # add new-line.
echo 'export PATH="/root/.pyenv/bin:$PATH"' >> ~/.bashrc
echo 'eval "$(pyenv init -)"' >> ~/.bashrc
echo 'eval "$(pyenv virtualenv-init -)"' >> ~/.bashrc
source ~/.bashrc

# build python 3.9.13 with pyenv
CONFIGURE_OPTS="--with-openssl=/usr/local --with-openssl-rpath=auto" pyenv install 3.9.13

# build python 3.10.5 with pyenv
CONFIGURE_OPTS="--with-openssl=/usr/local --with-openssl-rpath=auto" pyenv install 3.10.5

Answer 2

你可能已经安装好了

尝试运行$ python3 --version以查看您运行的python版本。如果未安装，请尝试运行$ sudo apt-get update，然后运行$ sudo apt-get install python3.9以安装python3.9

希望这能帮上忙

Answer 3

您将需要添加死蛇回购。

sudo add-apt-repository ppa:deadsnakes/ppa

在那之后，你可以按照你问题中的步骤。

如果在添加死蛇回购后仍然存在相同的问题，这可能意味着您运行的是不受支持的linux版本。然后您可能必须从源代码中安装Python3.9，您可以检查这个答案如何做到这一点。