Python is installed to all of our computers because it is useful framework for a variety of things .

To use the python interface from terminal just type python .

to check you python version just type python --version

to run a python script you need to type in the form :

./python_script_name.py

but very importantly it has to be executable first

chmod +x python_script_name.py

I hope it helps !

https://docs.python.org/3.6/using/windows.html#installing-without-ui

Installing Without UI: All of the options available in the installer UI can also be specified from the command line, allowing scripted installers to replicate an installation on many machines without user interaction. These options may also be set without suppressing the UI in order to change some of the defaults.

To completely hide the installer UI and install Python silently, pass the /quiet option. To skip past the user interaction but still display progress and errors, pass the /passive option. The /uninstall option may be passed to immediately begin removing Python - no prompt will be displayed.

All other options are passed as name=value, where the value is usually 0 to disable a feature, 1 to enable a feature, or a path.

If you are on Ubuntu 19.10 (Eoan Ermine) (or any other version unsupported by the deadsnakes PPA), you will not be able to install using the deadsnakes PPA.

What you can do instead, is get the source from Python's official website, and install it manually, as described here.

To do so, first, install the dependencies required to build the Python package.

sudo apt install build-essential zlib1g-dev \
libncurses5-dev libgdbm-dev libnss3-dev \
libssl-dev libreadline-dev libffi-dev curl software-properties-common

Then download the tarball and extract it:

wget https://www.python.org/ftp/python/3.9.0/Python-3.9.0.tar.xz
tar -xf Python-3.9.0.tar.xz

Then cd to the extracted directory:

cd Python-3.9.0

Now configure the script:

./configure

Now, to install Python 3.9 alongside your current Python installation (if any), use:

sudo make altinstall

Lastly, you can verify your installation using

python3.9 --version

How to make python3.X default of Python 3? (Optional)

rm /usr/bin/python3
ln -s /usr/bin/python3.5 /usr/bin/python3

• create an alias in ~/.bash_aliases, ~/.zshrc, etc.

alias python3='/usr/bin/python3.9'

or

alias python3='/usr/local/bin/python3.9'

A terminal in a unix-based OS (including Darwin / MacOS and Linux) will search for the command you have typed in several places, in order, and the first match found will stop the search from finding other possible commands with the same name.

To simplify the answer, I'll limit this to the bash shell as I don't use ZSH, but I think the answer should be similar in both shells.

After you type in a line of input and hit enter, your shell will modify its input so that it expands variable interpolations and such things and then will take the first token (first "word") and search for that word as a command name.

Commands can be found in several places, from builtin commands, to aliases, to shell functions and if the command can't be found there, the shell will begin looking at specific locations in your filesystem to look for files that are named the same as your command. The first match wins, so if you have several pythons in your PATH, the first one will be the one that is selected.

The set of locations in your filesystem the shell will look for the command is stored in an environment variable called PATH in the shell and is generally available to view and set.

to see what your path is:

echo ${PATH}

or. for slightly easier reading:

echo ${PATH} | sed 's/:/\n/g'

which python will let you see what python version your shell is finding first in the PATH and type python will let you know if for some reason you have a function or alias named python that happens to overshadow your filesystem python executables.

Also, bash maintains an internal hash table of where it has previously found commands. So if you type python and bash finds it in /usr/bin/python, then it will remember that for the rest of the session. If you'd like it to look again, because perhaps you have installed a new python you expect it to find first, you can type hash -r to reset the hash table to a blank new one.

All that being said, if you are starting to develop in Python, you're going to need to handle different versions of Python.

To start down that road, check out:

• asdf
• pyenv

I recommend asdf as it can work for many things, not just python. Also, you'll probably want a decent dependency manager sooner rather than later for your project, so I'd check out poetry and pipenv:

• Poetry
• Pipenv