Installing Python3 on Mac Big Sur

Mac comes with Python 2 by default and I wanted to install and use Python 3. I installed it by using brew: 

% brew install python3

Running `brew update --preinstall`...

==> Auto-updated Homebrew!

Updated 2 taps (homebrew/core and homebrew/cask).

==> New Formulae

abi-compliance-checker     gotify                     pam-reattach

abi-dumper                 hurl                       payload-dumper-go

biber                      imap-backup                pip-audit

brigade-cli                isa-l                      pocsuite3

chroma                     jsonschema                 rpki-client

coursier                   kubernetes-cli@1.22        salt-lint

djhtml                     lua-language-server        sevenzip

dynomite                   mcfly                      statix

fastp                      mist                       tsduck

goawk                      openliberty-jakartaee9     vtable-dumper

goplus                     openliberty-webprofile9

==> Updated Formulae

Updated 1431 formulae.

==> Deleted Formulae

ape             es              jerasure        makepp          swiftplate

balance         eventlog        kakasi          marst           torrentcheck

bbcolors        flasm           l-smash         mboxgrep        udns

colorsvn        fondu           libbind         md              whitedb

contacts        gconf           liberasurecode  namazu          xidel

csv-fix         gcore           libmill         postmark        xtail

dlite           gf-complete     libopendkim     redsocks        zdelta

dnsrend         git-hooks       libpuzzle       sdhash

drip            git-sh          libvbucket      shorten

dshb            henplus         m2c             srmio

eject           httptunnel      magnetix        svdlibc

==> New Casks

appflowy            finalshell          projector           teamspeak-client

appium-inspector    folder-colorizer    schildichat         tidgi

centered            grammarly-desktop   sitala              volley

citrix-workspace    handyprintpro       soundtoys           wolai

cron                linearmouse         spaceid             xstation5

emmetapp            ludwig              supermjograph

equinox             macrorecorder       tablecruncher

==> Updated Casks

Updated 648 casks.

==> Deleted Casks

air-connect                              lelivrescolairefr

aja-system-test                          napari

anka-build-cloud-registry                octoscreen

asc-timetables                           platelet

avast-secureline-vpn                     pullover

chameleon-ssd-optimizer                  punto-switcher

chocolat                                 qit

domainbrain                              river-sparkle

drama                                    scrutiny

everweb                                  tmnotifier

freeter                                  unity-linux-support-for-editor

gitbook                                  unity-lumin-support-for-editor

inboard                                  visicut

python@3.9 3.9.6 is already installed but outdated (so it will be upgraded).

==> Downloading https://ghcr.io/v2/homebrew/core/gdbm/manifests/1.22

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==> Downloading https://ghcr.io/v2/homebrew/core/gdbm/blobs/sha256:7e9737ec99942

==> Downloading from https://pkg-containers.githubusercontent.com/ghcr1/blobs/sh

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==> Downloading https://ghcr.io/v2/homebrew/core/ca-certificates/manifests/2021-

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==> Downloading https://ghcr.io/v2/homebrew/core/ca-certificates/blobs/sha256:1b

==> Downloading from https://pkg-containers.githubusercontent.com/ghcr1/blobs/sh

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==> Downloading https://ghcr.io/v2/homebrew/core/openssl/1.1/manifests/1.1.1m

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==> Downloading https://ghcr.io/v2/homebrew/core/readline/manifests/8.1.1

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==> Downloading https://ghcr.io/v2/homebrew/core/readline/blobs/sha256:c596199dc

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==> Downloading https://ghcr.io/v2/homebrew/core/sqlite/manifests/3.37.0

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==> Downloading https://ghcr.io/v2/homebrew/core/python/3.9/manifests/3.9.9

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==> Downloading https://ghcr.io/v2/homebrew/core/python/3.9/blobs/sha256:4b56d09

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==> Upgrading python3

  3.9.6 -> 3.9.9 

==> Installing dependencies for python@3.9: gdbm, ca-certificates, openssl@1.1, readline and sqlite

==> Installing python@3.9 dependency: gdbm

==> Pouring gdbm--1.22.big_sur.bottle.tar.gz

🍺  /usr/local/Cellar/gdbm/1.22: 24 files, 957.9KB

==> Installing python@3.9 dependency: ca-certificates

==> Pouring ca-certificates--2021-10-26.all.bottle.tar.gz

==> Regenerating CA certificate bundle from keychain, this may take a while...

🍺  /usr/local/Cellar/ca-certificates/2021-10-26: 3 files, 208.5KB

==> Installing python@3.9 dependency: openssl@1.1

==> Pouring openssl@1.1--1.1.1m.big_sur.bottle.tar.gz

🍺  /usr/local/Cellar/openssl@1.1/1.1.1m: 8,081 files, 18.5MB

==> Installing python@3.9 dependency: readline

==> Pouring readline--8.1.1.big_sur.bottle.tar.gz

🍺  /usr/local/Cellar/readline/8.1.1: 48 files, 1.6MB

==> Installing python@3.9 dependency: sqlite

==> Pouring sqlite--3.37.0.big_sur.bottle.tar.gz

🍺  /usr/local/Cellar/sqlite/3.37.0: 11 files, 4.3MB

==> Installing python@3.9

==> Pouring python@3.9--3.9.9.big_sur.bottle.tar.gz

==> /usr/local/Cellar/python@3.9/3.9.9/bin/python3 -m ensurepip

==> /usr/local/Cellar/python@3.9/3.9.9/bin/python3 -m pip install -v --no-deps -

==> Caveats

Python has been installed as

  /usr/local/bin/python3

Unversioned symlinks `python`, `python-config`, `pip` etc. pointing to

`python3`, `python3-config`, `pip3` etc., respectively, have been installed into

  /usr/local/opt/python@3.9/libexec/bin

You can install Python packages with

  pip3 install <package>

They will install into the site-package directory

  /usr/local/lib/python3.9/site-packages

tkinter is no longer included with this formula, but it is available separately:

  brew install python-tk@3.9

See: https://docs.brew.sh/Homebrew-and-Python

==> Summary

🍺  /usr/local/Cellar/python@3.9/3.9.9: 3,080 files, 55.0MB

==> `brew cleanup` has not been run in the last 30 days, running now...

Disable this behaviour by setting HOMEBREW_NO_INSTALL_CLEANUP.

Hide these hints with HOMEBREW_NO_ENV_HINTS (see `man brew`).

Removing: /usr/local/Cellar/gdbm/1.20... (24 files, 825.0KB)

Removing: /Users/bojan/Library/Caches/Homebrew/gdbm--1.20... (221KB)

Removing: /Users/bojan/Library/Caches/Homebrew/mpdecimal--2.5.1... (548.3KB)

Removing: /usr/local/Cellar/openssl@1.1/1.1.1k... (8,071 files, 18.5MB)

Removing: /Users/bojan/Library/Caches/Homebrew/openssl@1.1--1.1.1k... (5.4MB)

Removing: /usr/local/Cellar/python@3.9/3.9.6... (3,085 files, 54.7MB)

Removing: /Users/bojan/Library/Caches/Homebrew/python@3.9--3.9.6... (13.6MB)

Removing: /usr/local/Cellar/readline/8.1... (48 files, 1.6MB)

Removing: /Users/bojan/Library/Caches/Homebrew/readline--8.1... (536KB)

Removing: /Users/bojan/Library/Caches/Homebrew/rtmpdump--2.4+20151223_1... (170.2KB)

Removing: /usr/local/Cellar/sqlite/3.36.0... (11 files, 4.2MB)

Removing: /Users/bojan/Library/Caches/Homebrew/sqlite--3.36.0... (2MB)

Removing: /Users/bojan/Library/Caches/Homebrew/xz--5.2.5... (417.6KB)

Removing: /Users/bojan/Library/Caches/Homebrew/you-get--0.4.1536... (2.2MB)

Removing: /Users/bojan/Library/Caches/Homebrew/xz_bottle_manifest--5.2.5... (5.7KB)

Removing: /Users/bojan/Library/Caches/Homebrew/rtmpdump_bottle_manifest--2.4+20151223_1... (7KB)

Removing: /Users/bojan/Library/Caches/Homebrew/sqlite_bottle_manifest--3.36.0... (5.9KB)

Removing: /Users/bojan/Library/Caches/Homebrew/openssl@1.1_bottle_manifest--1.1.1k... (6KB)

Removing: /Users/bojan/Library/Caches/Homebrew/python@3.9_bottle_manifest--3.9.6... (15.4KB)

Removing: /Users/bojan/Library/Caches/Homebrew/readline_bottle_manifest--8.1... (5.5KB)

Removing: /Users/bojan/Library/Caches/Homebrew/you-get_bottle_manifest--0.4.1536... (11.2KB)

Removing: /Users/bojan/Library/Caches/Homebrew/gdbm_bottle_manifest--1.20... (5.2KB)

Removing: /Users/bojan/Library/Caches/Homebrew/mpdecimal_bottle_manifest--2.5.1... (5.2KB)

Removing: /Users/bojan/Library/Logs/Homebrew/gdbm... (64B)

Removing: /Users/bojan/Library/Logs/Homebrew/mpdecimal... (64B)

Removing: /Users/bojan/Library/Logs/Homebrew/rtmpdump... (64B)

Removing: /Users/bojan/Library/Logs/Homebrew/readline... (64B)

Removing: /Users/bojan/Library/Logs/Homebrew/sqlite... (64B)

Removing: /Users/bojan/Library/Logs/Homebrew/xz... (64B)

Removing: /Users/bojan/Library/Logs/Homebrew/openssl@1.1... (64B)

Removing: /Users/bojan/Library/Logs/Homebrew/you-get... (64B)

Removing: /Users/bojan/Library/Logs/Homebrew/python@3.9... (2 files, 2.4KB)

Pruned 0 symbolic links and 2 directories from /usr/local

==> Upgrading 1 dependent:

Disable this behaviour by setting HOMEBREW_NO_INSTALLED_DEPENDENTS_CHECK.

Hide these hints with HOMEBREW_NO_ENV_HINTS (see `man brew`).

you-get 0.4.1536 -> 0.4.1555

==> Downloading https://ghcr.io/v2/homebrew/core/python/3.10/manifests/3.10.1

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==> Downloading https://ghcr.io/v2/homebrew/core/python/3.10/blobs/sha256:c4f29a

==> Downloading from https://pkg-containers.githubusercontent.com/ghcr1/blobs/sh

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==> Downloading https://ghcr.io/v2/homebrew/core/you-get/manifests/0.4.1555

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==> Downloading https://ghcr.io/v2/homebrew/core/you-get/blobs/sha256:df0dc12c74

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==> Upgrading you-get

  0.4.1536 -> 0.4.1555 

==> Installing dependencies for you-get: python@3.10

==> Installing you-get dependency: python@3.10

==> Pouring python@3.10--3.10.1.big_sur.bottle.tar.gz

==> /usr/local/Cellar/python@3.10/3.10.1/bin/python3 -m ensurepip

==> /usr/local/Cellar/python@3.10/3.10.1/bin/python3 -m pip install -v --no-deps

🍺  /usr/local/Cellar/python@3.10/3.10.1: 3,132 files, 56MB

==> Installing you-get

==> Pouring you-get--0.4.1555.big_sur.bottle.tar.gz

==> Caveats

To use post-processing options, run `brew install ffmpeg` or `brew install libav`.

==> Summary

🍺  /usr/local/Cellar/you-get/0.4.1555: 736 files, 8.5MB

==> Running `brew cleanup you-get`...

Removing: /usr/local/Cellar/you-get/0.4.1536... (845 files, 8.6MB)

==> Checking for dependents of upgraded formulae...

==> No broken dependents found!

==> Caveats

==> python@3.9

Python has been installed as

  /usr/local/bin/python3

Unversioned symlinks `python`, `python-config`, `pip` etc. pointing to

`python3`, `python3-config`, `pip3` etc., respectively, have been installed into

  /usr/local/opt/python@3.9/libexec/bin

You can install Python packages with

  pip3 install <package>

They will install into the site-package directory

  /usr/local/lib/python3.9/site-packages

tkinter is no longer included with this formula, but it is available separately:

  brew install python-tk@3.9

See: https://docs.brew.sh/Homebrew-and-Python

==> you-get

To use post-processing options, run `brew install ffmpeg` or `brew install libav`.

% 

If zsh configuration file does not exist, create it and open it:

% touch ~/.zshrc

% vi ~/.zshrc

Type in it:

export PATH=/usr/local/opt/python@3.9/libexec/bin:$PATH

Restart the terminal.

% which python

/usr/local/opt/python@3.9/libexec/bin/python

% python --version

Python 3.9.9

If using VSCode, restart it and it will also pick up this version of Python in its Terminal.