Debian Manually Upgrade Python3 over 3.6

deps

build-essential, libncurses5-dev, libncursesw5-dev, libreadline6-dev,

libdb5.3-dev, libgdbm-dev, libsqlite3-dev, libssl-dev, libbz2-dev,

libexpat1-dev, liblzma-dev, zlib1g-dev, ca-certificates, make, wget, curl,

llvm, xz-utils, tk-dev, libffi-dev, libedit-dev

library so soft link

ln /usr/lib/x86_64-linux-gnu/libcrypto.so.1.0.0 /usr/local/libcrypto.so

ln /usr/lib/x86_64-linux-gnu/libssl.so.1.0.0 /usr/local/libssl.so

download package and compile install

cd 

sudo wget https://www.python.org/ftp/python/3.6.10/Python-3.6.10.tar.xz

tar -Jxvf Python-3.6.10.tar.xz

cd Python-3.6.10 && pwd && ls -a

./configure --enable-optimizations --enable-shared

make -j8

sudo make altinstall

Manually installed(git clone/wget/curl) python3(python3.6) active files are

located at "/usr/local/bin", library files are located at "/usr/local/lib"

Default installed(apt/apt-get install) python3(python3.4) is located at

"/usr/bin".

Just use this to enter Python3.6:

python3.6

But output error:

python3: error while loading shared libraries: libpython3.6m.so.1.0: cannot open shared object file: No such file or directory

The upstairs fixed:

cd ~

vim ~/.zshrc

Add the below code to ~/.zshrc:

export LD_LIBRARY_PATH=$LD_LIBRARY_PATH:/usr/local/lib/

Also, active the hewable .zshrc:

source ~/.zshrc

set to default python3

sudo update-alternatives --install /usr/bin/python3 python3 /usr/bin/python3.4 30

sudo update-alternatives --install /usr/bin/python3 python3 /usr/local/bin/python3.6 50

refer

How to install Python 3.6?

How to install Python from future releases of Debian.

How to Upgrade Python to 3.9.