Develop Reference

ElasticBeanstalk PHP with Python - Install packages with pip [duplicate]

I want to install pip. It should support Python 3, but it requires setuptools, which is available only for Python 2.
How can I install pip with Python 3?

edit: Manual installation and use of setuptools is not the standard process anymore.
If you're running Python 2.7.9+ or Python 3.4+
Congrats, you should already have pip installed. If you do not, read onward.
If you're running a Unix-like System
You can usually install the package for pip through your package manager if your version of Python is older than 2.7.9 or 3.4, or if your system did not include it for whatever reason.
Instructions for some of the more common distros follow.
Installing on Debian (Wheezy and newer) and Ubuntu (Trusty Tahr and newer) for Python 2.x
Run the following command from a terminal:
sudo apt-get install python-pip
Installing on Debian (Wheezy and newer) and Ubuntu (Trusty Tahr and newer) for Python 3.x
Run the following command from a terminal:
sudo apt-get install python3-pip
Note:
On a fresh Debian/Ubuntu install, the package may not be found until you do:
sudo apt-get update
Installing pip on CentOS 7 for Python 2.x
On CentOS 7, you have to install setup tools first, and then use that to install pip, as there is no direct package for it.
sudo yum install python-setuptools
sudo easy_install pip
Installing pip on CentOS 7 for Python 3.x
Assuming you installed Python 3.4 from EPEL, you can install Python 3's setup tools and use it to install pip.
# First command requires you to have enabled EPEL for CentOS7
sudo yum install python34-setuptools
sudo easy_install pip
If your Unix/Linux distro doesn't have it in package repos
Install using the manual way detailed below.
The manual way
If you want to do it the manual way, the now-recommended method is to install using the get-pip.py script from pip's installation instructions.
Install pip
To install pip, securely download get-pip.py
Then run the following (which may require administrator access):
python get-pip.py
If setuptools is not already installed, get-pip.py will install setuptools for you.

I was able to install pip for python 3 on Ubuntu just by running sudo apt-get install python3-pip.

Python 3.4+ and Python 2.7.9+
Good news! Python 3.4 (released March 2014) ships with Pip. This is the best feature of any Python release. It makes the community's wealth of libraries accessible to everyone. Newbies are no longer excluded by the prohibitive difficulty of setup. In shipping with a package manager, Python joins Ruby, Nodejs, Haskell, Perl, Go--almost every other contemporary language with a majority open-source community. Thank you Python.
Of course, that doesn't mean Python packaging is problem solved. The experience remains frustrating. I discuss this at Does Python have a package/module management system?
Alas for everyone using an earlier Python. Manual instructions follow.
Python ≤ 2.7.8 and Python ≤ 3.3
Follow my detailed instructions at https://stackoverflow.com/a/12476379/284795 . Essentially
Official instructions
Per https://pip.pypa.io/en/stable/installing.html
Download get-pip.py, being careful to save it as a .py file rather than .txt. Then, run it from the command prompt.
python get-pip.py
You possibly need an administrator command prompt to do this. Follow http://technet.microsoft.com/en-us/library/cc947813(v=ws.10).aspx
For me, this installed Pip at C:\Python27\Scripts\pip.exe. Find pip.exe on your computer, then add its folder (eg. C:\Python27\Scripts) to your path (Start / Edit environment variables). Now you should be able to run pip from the command line. Try installing a package:
pip install httpie
There you go (hopefully)!

if you're using python 3.4+
just type:
python3 -m pip

For Ubuntu 12.04 or older,
sudo apt-get install python3-pip
won't work. Instead, use:
sudo apt-get install python3-setuptools ca-certificates
sudo easy_install3 pip

Update 2015-01-20:
As per https://pip.pypa.io/en/latest/installing.html the current way is:
wget https://bootstrap.pypa.io/get-pip.py
python get-pip.py
I think that should work for any version
Original Answer:
wget http://python-distribute.org/distribute_setup.py
python distribute_setup.py
easy_install pip

Single Python in system
To install packages in Python always follow these steps:
If the package is for python 2.x: sudo python -m pip install [package]
If the package is for python 3.x: sudo python3 -m pip install [package]
Note: This is assuming no alias is set for python
Through this method, there will be no confusion regarding which python version is receiving the package.
Multiple Pythons/Virtual Envs
Say you have python3 ↔ python3.6 and python3.7 ↔ python3.7
To install for python3.6: sudo python3 -m pip install [package]
To instal for python3.7: sudo python3.7 -m pip install [package]
This is essentially the same method as shown previously.
Note 1
How to find which python? Do one of the following:
~ » python3 -c "import sys; print(sys.version)"
3.9.5 (default, Nov 18 2021, 16:00:48)
your python3 command spawns:
~ » python3
Python 3.9.5 (default, Nov 18 2021, 16:00:48)
[GCC 10.3.0] on linux
Type "help", "copyright", "credits" or "license" for more information.
>>>
Notice python 3.9.5 in the second line.
or say you are using virtual env and see where your python points to:
» which python
/home/ganesh/os/np-test/bin/python
Note 2
Change what python3 or python points to: https://askubuntu.com/questions/320996/how-to-make-python-program-command-execute-python-3

python3 -m ensurepip
I'm not sure when exactly this was introduced, but it's installed pip3 for me when it didn't already exist.

Older version of Homebrew
If you are on macOS, use homebrew.
brew install python3 # this installs python only
brew postinstall python3 # this command installs pip
Also note that you should check the console if the install finished successfully. Sometimes it doesn't (e.g. an error due to ownership), but people simply overlook the log.
UPDATED - Homebrew version after 1.5
According to the official Homebrew page:
On 1st March 2018 the python formula will be upgraded to Python 3.x and a python#2 formula will be added for installing Python 2.7 (although this will be keg-only so neither python nor python2 will be added to the PATH by default without a manual brew link --force). We will maintain python2, python3 and python#3 aliases.
So to install Python 3, run the following command:
brew install python3
Then, the pip is installed automatically, and you can install any package by pip install <package>.

If your Linux distro came with Python already installed, you should be able to install PIP using your system’s package manager. This is preferable since system-installed versions of Python do not play nicely with the get-pip.py script used on Windows and Mac.
Advanced Package Tool (Python 2.x)
sudo apt-get install python-pip
Advanced Package Tool (Python 3.x)
sudo apt-get install python3-pip
pacman Package Manager (Python 2.x)
sudo pacman -S python2-pip
pacman Package Manager (Python 3.x)
sudo pacman -S python-pip
Yum Package Manager (Python 2.x)
sudo yum upgrade python-setuptools
sudo yum install python-pip python-wheel
Yum Package Manager (Python 3.x)
sudo yum install python3 python3-wheel
Dandified Yum (Python 2.x)
sudo dnf upgrade python-setuptools
sudo dnf install python-pip python-wheel
Dandified Yum (Python 3.x)
sudo dnf install python3 python3-wheel
Zypper Package Manager (Python 2.x)
sudo zypper install python-pip python-setuptools python-wheel
Zypper Package Manager (Python 3.x)
sudo zypper install python3-pip python3-setuptools python3-wheel

This is the one-liner I copy-and-paste:
curl https://bootstrap.pypa.io/get-pip.py | python3
Alternate:
curl -L get-pip.io | python3
From Installing with get-pip.py:
To install pip, securely download get-pip.py by following this link:
get-pip.py. Alternatively, use
curl:
curl https://bootstrap.pypa.io/get-pip.py -o get-pip.py
Then run the following command in the folder where you have downloaded
get-pip.py:
python get-pip.py
Warning: Be cautious if you are using a Python install that is managed
by your operating system or another package manager. get-pip.py does
not coordinate with those tools, and may leave your system in an
inconsistent state.

If you use several different versions of python try using virtualenv http://www.virtualenv.org/en/latest/virtualenv.html#installation
With the advantage of pip for each local environment.
Then install a local environment in the current directory by:
virtualenv -p /usr/local/bin/python3.3 ENV --verbose
Note that you specify the path to a python binary you have installed on your system.
Then there are now an local pythonenvironment in that folder. ./ENV
Now there should be ./ENV/pip-3.3
use
./ENV/pip-3.3 freeze to list the local installed libraries.
use ./ENV/pip-3.3 install packagename to install at the local environment.
use ./ENV/python3.3 pythonfile.py to run your python script.

Here is my way to solve this problem at ubuntu 12.04:
sudo apt-get install build-essential libncursesw5-dev libssl-dev libgdbm-dev libc6-dev libsqlite3-dev tk-dev
Then install the python3 from source code:
wget https://www.python.org/ftp/python/3.4.0/Python-3.4.0.tar.xz
tar xvf Python-3.4.0.tar.xz
cd Python-3.4.0
./configure
make
make test
sudo make install
When you finished installing all of them, pip3 will get installed automatically.

This is what I did on OS X Mavericks to get this to work.
Firstly, have brew installed
Install python 3.4
brew install python3
Then I get the latest version of distribute:
wget https://pypi.python.org/packages/source/d/distribute/distribute-0.7.3.zip#md5=c6c59594a7b180af57af8a0cc0cf5b4a
unzip distribute-0.7.3.zip
cd distribute-0.7.3
sudo setup.py install
sudo easy_install-3.4 pip
sudo pip3.4 install virtualenv
sudo pip3.4 install virtualenvwrapper
mkvirtualenv py3
python --version
Python 3.4.1
I hope this helps.

pip is installed together when you install Python. You can use
sudo pip install (module)
or
python3 -m pip install (module).

Please follow below steps to install python 3 with pip:
Step 1 : Install Python from download here
Step 2 : you’ll need to download get-pip.py
Step 3 : After download get-pip.py , open your commant prompt and go to directory where your get-pip.py file saved .
Step 4 : Enter command python get-pip.py in cmd.
Step 5 : Pip installed successfully , Verify pip installation by type command in cmd pip --version

What’s New In Python 3.4
...
pip should always be available
...
By default, the commands pipX and pipX.Y will be installed on all platforms (where X.Y stands for the version of the Python installation), along with the pip Python package and its dependencies.
https://docs.python.org/3/whatsnew/3.4.html#whatsnew-pep-453
so if you have python 3.4 installed, you can just: sudo pip3 install xxx

For python3 try this:
wget https://bitbucket.org/pypa/setuptools/raw/bootstrap/ez_setup.py -O - | python
The good thing is that It will also detect what version of python you have (even if it's an environment of python in your custom location).
After this you can proceed normally with (for example)
pip install numpy
source:
https://pypi.python.org/pypi/setuptools/1.1.6#upgrading-from-setuptools-0-6

Assuming you are in a highly restricted computer env (such as myself) without root access or ability to install packages...
I had never setup a fresh/standalone/raw/non-root instance of Python+virtualenv before this post. I had do quite a bit of Googling to make this work.
Decide if you are using python (python2) or python3 and set your PATH correctly. (I am strictly a python3 user.) All commands below can substitute python3 for python if you are python2 user.
wget https://pypi.python.org/packages/source/v/virtualenv/virtualenv-x.y.z.tar.gz
tar -xzvf virtualenv-x.y.z.tar.gz
python3 virtualenv-x.y.z/virtualenv.py --python $(which python3) /path/to/new/virtualenv
source /path/to/new/virtualenv/bin/activate
Assumes you are using a Bourne-compatible shell, e.g., bash
Brilliantly, this virtualenv package includes a standalone version of pip and setuptools that are auto-magically installed into each new virtualenv. This solves the chicken and egg problem.
You may want to create an alias (or update your ~/.bashrc, etc.) for this final command to activate the python virtualenv during each login. It can be a pain to remember all these paths and commands.
Check your version of python now: which python3 should give: /path/to/new/virtualenv/bin/python3
Check pip is also available in the virtualenv via which pip... should give: /path/to/new/virtualenv/bin/pip
Then... pip, pip, pip!
Final tip to newbie Pythoneers: You don't think you need virtualenv when you start, but you will be happy to have it later. Helps with "what if" installation / upgrade scenarios for open source / shared packages.
Ref: https://virtualenv.pypa.io/en/latest/installation.html

To install pip, securely download get-pip.py.
Then run the following:
python get-pip.py
Be cautious if you're using a Python install that's managed by your
operating system or another package manager. get-pip.py does not
coordinate with those tools, and may leave your system in an
inconsistent state.
Refer: PIP Installation

And for Windows 8.1/10 OS Users just open cmd (command prompt)
write this : C:\Users\%USERNAME%\AppData\Local\Programs\Python\Python36-32\Scripts
then
just write this : pip3 install {name of package}
Hint: the location of folder Python36-32 may get different for new python 3.x versions

If you used the command "python get-pip.py", you should have the 'pip' function for Python3. However, 'pip' for Python2 might still be present. In my case I uninstalled 'pip', which removed it from Python2.
After that I ran "python get-pip.py" again. (Make sure that 'get-pip.py' is saved in the same folder as Python3.) The final step was to add the directory with 'pip' command to $PATH. That solved it for me.

=>Easy way to install Python any version on Ubuntu 18.04 or Ubuntu 20.04 follow these steps:-
Step 1: Update Local Repositories:-
sudo apt update
Step 2: Install Supporting Software:-
sudo apt install build-essential zlib1g-dev libncurses5-dev libgdbm-dev libnss3-dev libssl-dev libreadline-dev libffi-dev wget
Step3: Create directory on your home directory To download the newest release of Python Source Code, navigate to the /python-source-files directory and use the wget command:-
mkdir python-source-files
Step 4: Download the Latest Version of Python Source Code:-
wget https://www.python.org/ftp/python/3.7.5/Python-3.7.5.tgz
"you can change python version by just modifies this:-"3.7.5" with the version you want example:-"3.5.2"
Step 5: Extract Compressed Files:-
tar –xf Python-3.7.5.tgz
or
tar xvzf Python-3.7.5.tgz
Step 6: Test System and Optimize Python:-
cd python-3.7.5 or your version of python.
Step 7: Now configure(Using the ––optimization option speeds code execution by 10-20%.):-
./configure ––enable–optimizations
OR you can also do this also if you facing ssl error:-
./configure --with-openssl
Step 8: Install a Second Instance of Python:-
sudo make altinstall
"It is recommended that you use the altinstall method. Your Ubuntu system may have software packages dependent on Python 2.x.
OR
If you want to Overwrite Default Python Installation/version:-
sudo make install"
Step 9:Now check Python Version:-
python3 ––version
Step 10: To install pip for python3 just go with this command:-
sudo apt-get install python3-pip

How do I install pip for python 3.8 on Ubuntu without changing any defaults?

I'm trying to install pip for Python 3.8 on an Ubuntu 18.04 LTS.
I know this has been asked way too many times. But those questions do not concern keeping Ubuntu's defaults specifically. And the answers on those questions either don't work or go on to suggest something so drastic that it would break the system - e.g. change default python3 version from 3.6 to 3.8. You SHOULDN'T!
So far, I've been able to install python3.8 successfully using the PPA - ppa:deadsnakes/ppa:
sudo add-apt-repository ppa:deadsnakes/ppa
sudo apt update
sudo apt install python3.8
Changed python command from python2 to python3.8 using update-alternatives:
update-alternatives --remove python /usr/bin/python2
sudo update-alternatives --install /usr/bin/python python /usr/bin/python3.8 10
Now, I get python 3.8 when I run python --version:
Python 3.8.5
The problem is, I still can't install pip for Python 3.8.
If I try to install python3-pip, it installs pip for Python 3.6 since python3 still points to python3.6.9, and I intend to keep it that way.
Try installing python-pip, and it will install pip for Python 2.7.
Also there's no such package as python3.8-pip, so I can't install it like:
sudo apt install python3.8-pip
Output:
E: Unable to locate package python3.8-pip
E: Couldn't find any package by glob 'python3.8-pip'
E: Couldn't find any package by regex 'python3.8-pip'
What can I do to install pip for Python 3.8 on an Ubuntu 18.04?

While we can use pip directly as a Python module (the recommended way):
python -m pip --version
This is how I installed it (so it can be called directly):
Firstly, make sure that command pip is available and it isn't being used by pip for Python 2.7
sudo apt remove python-pip
Now if you write pip in the Terminal, you'll get that nothing is installed there:
pip --version
Output:
Command 'pip' not found, but can be installed with:
sudo apt install python-pip
Install python3.8 and setup up correct version on python command using update-alternatives (as done in the question).
Make sure, you have python3-pip installed:
(This won't work without python3-pip. Although this will install pip 9.0.1 from python 3.6, we'll need it.)
sudo apt install python3-pip
This will install pip 9.0.1 as pip3:
pip3 --version
Output:
pip 9.0.1 from /usr/lib/python3/dist-packages (python 3.6)
Now, to install pip for Python 3.8, I used pip by calling it as a python module (ironic!):
python -m pip install pip
Output:
Collecting pip
  Downloading https://files.pythonhosted.org/packages/36/74/38c2410d688ac7b48afa07d413674afc1f903c1c1f854de51dc8eb2367a5/pip-20.2-py2.py3-none-any.whl (1.5MB)
  100% |████████████████████████████████| 1.5MB 288kB/s
Installing collected packages: pip
Successfully installed pip-20.2
It looks like, when I called pip (which was installed for Python 3.6, BTW) as a module of Python 3.8, and installed pip, it actually worked.
Now, make sure your ~/.local/bin directory is set in PATH environment variable:
Open ~/.bashrc using your favourite editor (if you're using zsh, replace .bashrc with .zshrc)
nano ~/.bashrc
And paste the following at the end of the file
# set PATH so it includes user's private bin if it exists
if [ -d "$HOME/.local/bin" ] ; then
PATH="$HOME/.local/bin:$PATH"
fi
Finally, source your .bashrc (or restart the Terminal window):
source ~/.bashrc
Now if you try running pip directly it'll give you the correct version:
pip --version
Output:
pip 20.2 from /home/qumber/.local/lib/python3.8/site-packages/pip (python 3.8)
Sweet!

As suggested in official documentation you can try with get-pip.py.
wget https://bootstrap.pypa.io/get-pip.py
python3.8 get-pip.py
This will install pip as pip3.8

Another solution would be to install the pip that is in apt. sudo apt install python3-pip. The version of the pip that it installs is for all versions of Python not only for version 3.6 once installed you just need to update the pip with the command python3.8 -m pip install pip and he will be install the latest version of pip for Python.
I would not advise you to remove Python2 because it is an important module for the system you should just create a permanent "alias" in .bashrc for Python3 I did like this alias python="python3.8.

# install py3.8 and dependencies for the pip3 bootstrap script
add-apt-repository -y ppa:deadsnakes/ppa && \
apt install -y python3.8 python3.8-distutils
# download and run the pip3 bootstrap script
cd /tmp && wget https://bootstrap.pypa.io/get-pip.py && \
python3.8 /tmp/get-pip.py
# use pip py3.8 module to install python packages
python3.8 -m pip install numpy pandas

Install python v3.8 as python
RUN apt update --fix-missing && \
apt install python3.8 -y && \
update-alternatives --install /usr/bin/python python /usr/bin/python3.8 10
Install pip for python 3.8
RUN apt install python3-pip -y && \
python -m pip install --upgrade pip

I did this a couple days ago and I struggled a lot with it but I finally got it working, so I wrote up what I did as a blog post.
In the end I think I may have done mostly the same things as the above answer, but if you got lost following it, maybe my screenshots etc will help.
Here's the tl;dr of the process I did:
Uninstall python3-pip & python-pip using apt
Remove the old pip files from /usr/local/bin
Reinstall python3-pip using apt
Add $HOME/.local/bin to your $PATH (also restart your shell to make sure you did this right)

On ubuntu server
sudo apt install python -y
For more information check this blog here.
https://teckresolve.com/install-python-packages-using-pip/

How do I install pip3 for Python3 without root privileges on CentOS 7.6? [duplicate]

I want to install pip. It should support Python 3, but it requires setuptools, which is available only for Python 2.
How can I install pip with Python 3?

edit: Manual installation and use of setuptools is not the standard process anymore.
If you're running Python 2.7.9+ or Python 3.4+
Congrats, you should already have pip installed. If you do not, read onward.
If you're running a Unix-like System
You can usually install the package for pip through your package manager if your version of Python is older than 2.7.9 or 3.4, or if your system did not include it for whatever reason.
Instructions for some of the more common distros follow.
Installing on Debian (Wheezy and newer) and Ubuntu (Trusty Tahr and newer) for Python 2.x
Run the following command from a terminal:
sudo apt-get install python-pip
Installing on Debian (Wheezy and newer) and Ubuntu (Trusty Tahr and newer) for Python 3.x
Run the following command from a terminal:
sudo apt-get install python3-pip
Note:
On a fresh Debian/Ubuntu install, the package may not be found until you do:
sudo apt-get update
Installing pip on CentOS 7 for Python 2.x
On CentOS 7, you have to install setup tools first, and then use that to install pip, as there is no direct package for it.
sudo yum install python-setuptools
sudo easy_install pip
Installing pip on CentOS 7 for Python 3.x
Assuming you installed Python 3.4 from EPEL, you can install Python 3's setup tools and use it to install pip.
# First command requires you to have enabled EPEL for CentOS7
sudo yum install python34-setuptools
sudo easy_install pip
If your Unix/Linux distro doesn't have it in package repos
Install using the manual way detailed below.
The manual way
If you want to do it the manual way, the now-recommended method is to install using the get-pip.py script from pip's installation instructions.
Install pip
To install pip, securely download get-pip.py
Then run the following (which may require administrator access):
python get-pip.py
If setuptools is not already installed, get-pip.py will install setuptools for you.

I was able to install pip for python 3 on Ubuntu just by running sudo apt-get install python3-pip.

Python 3.4+ and Python 2.7.9+
Good news! Python 3.4 (released March 2014) ships with Pip. This is the best feature of any Python release. It makes the community's wealth of libraries accessible to everyone. Newbies are no longer excluded by the prohibitive difficulty of setup. In shipping with a package manager, Python joins Ruby, Nodejs, Haskell, Perl, Go--almost every other contemporary language with a majority open-source community. Thank you Python.
Of course, that doesn't mean Python packaging is problem solved. The experience remains frustrating. I discuss this at Does Python have a package/module management system?
Alas for everyone using an earlier Python. Manual instructions follow.
Python ≤ 2.7.8 and Python ≤ 3.3
Follow my detailed instructions at https://stackoverflow.com/a/12476379/284795 . Essentially
Official instructions
Per https://pip.pypa.io/en/stable/installing.html
Download get-pip.py, being careful to save it as a .py file rather than .txt. Then, run it from the command prompt.
python get-pip.py
You possibly need an administrator command prompt to do this. Follow http://technet.microsoft.com/en-us/library/cc947813(v=ws.10).aspx
For me, this installed Pip at C:\Python27\Scripts\pip.exe. Find pip.exe on your computer, then add its folder (eg. C:\Python27\Scripts) to your path (Start / Edit environment variables). Now you should be able to run pip from the command line. Try installing a package:
pip install httpie
There you go (hopefully)!

if you're using python 3.4+
just type:
python3 -m pip

For Ubuntu 12.04 or older,
sudo apt-get install python3-pip
won't work. Instead, use:
sudo apt-get install python3-setuptools ca-certificates
sudo easy_install3 pip

Update 2015-01-20:
As per https://pip.pypa.io/en/latest/installing.html the current way is:
wget https://bootstrap.pypa.io/get-pip.py
python get-pip.py
I think that should work for any version
Original Answer:
wget http://python-distribute.org/distribute_setup.py
python distribute_setup.py
easy_install pip

Single Python in system
To install packages in Python always follow these steps:
If the package is for python 2.x: sudo python -m pip install [package]
If the package is for python 3.x: sudo python3 -m pip install [package]
Note: This is assuming no alias is set for python
Through this method, there will be no confusion regarding which python version is receiving the package.
Multiple Pythons/Virtual Envs
Say you have python3 ↔ python3.6 and python3.7 ↔ python3.7
To install for python3.6: sudo python3 -m pip install [package]
To instal for python3.7: sudo python3.7 -m pip install [package]
This is essentially the same method as shown previously.
Note 1
How to find which python? Do one of the following:
~ » python3 -c "import sys; print(sys.version)"
3.9.5 (default, Nov 18 2021, 16:00:48)
your python3 command spawns:
~ » python3
Python 3.9.5 (default, Nov 18 2021, 16:00:48)
[GCC 10.3.0] on linux
Type "help", "copyright", "credits" or "license" for more information.
>>>
Notice python 3.9.5 in the second line.
or say you are using virtual env and see where your python points to:
» which python
/home/ganesh/os/np-test/bin/python
Note 2
Change what python3 or python points to: https://askubuntu.com/questions/320996/how-to-make-python-program-command-execute-python-3

python3 -m ensurepip
I'm not sure when exactly this was introduced, but it's installed pip3 for me when it didn't already exist.

Older version of Homebrew
If you are on macOS, use homebrew.
brew install python3 # this installs python only
brew postinstall python3 # this command installs pip
Also note that you should check the console if the install finished successfully. Sometimes it doesn't (e.g. an error due to ownership), but people simply overlook the log.
UPDATED - Homebrew version after 1.5
According to the official Homebrew page:
On 1st March 2018 the python formula will be upgraded to Python 3.x and a python#2 formula will be added for installing Python 2.7 (although this will be keg-only so neither python nor python2 will be added to the PATH by default without a manual brew link --force). We will maintain python2, python3 and python#3 aliases.
So to install Python 3, run the following command:
brew install python3
Then, the pip is installed automatically, and you can install any package by pip install <package>.

If your Linux distro came with Python already installed, you should be able to install PIP using your system’s package manager. This is preferable since system-installed versions of Python do not play nicely with the get-pip.py script used on Windows and Mac.
Advanced Package Tool (Python 2.x)
sudo apt-get install python-pip
Advanced Package Tool (Python 3.x)
sudo apt-get install python3-pip
pacman Package Manager (Python 2.x)
sudo pacman -S python2-pip
pacman Package Manager (Python 3.x)
sudo pacman -S python-pip
Yum Package Manager (Python 2.x)
sudo yum upgrade python-setuptools
sudo yum install python-pip python-wheel
Yum Package Manager (Python 3.x)
sudo yum install python3 python3-wheel
Dandified Yum (Python 2.x)
sudo dnf upgrade python-setuptools
sudo dnf install python-pip python-wheel
Dandified Yum (Python 3.x)
sudo dnf install python3 python3-wheel
Zypper Package Manager (Python 2.x)
sudo zypper install python-pip python-setuptools python-wheel
Zypper Package Manager (Python 3.x)
sudo zypper install python3-pip python3-setuptools python3-wheel

This is the one-liner I copy-and-paste:
curl https://bootstrap.pypa.io/get-pip.py | python3
Alternate:
curl -L get-pip.io | python3
From Installing with get-pip.py:
To install pip, securely download get-pip.py by following this link:
get-pip.py. Alternatively, use
curl:
curl https://bootstrap.pypa.io/get-pip.py -o get-pip.py
Then run the following command in the folder where you have downloaded
get-pip.py:
python get-pip.py
Warning: Be cautious if you are using a Python install that is managed
by your operating system or another package manager. get-pip.py does
not coordinate with those tools, and may leave your system in an
inconsistent state.

If you use several different versions of python try using virtualenv http://www.virtualenv.org/en/latest/virtualenv.html#installation
With the advantage of pip for each local environment.
Then install a local environment in the current directory by:
virtualenv -p /usr/local/bin/python3.3 ENV --verbose
Note that you specify the path to a python binary you have installed on your system.
Then there are now an local pythonenvironment in that folder. ./ENV
Now there should be ./ENV/pip-3.3
use
./ENV/pip-3.3 freeze to list the local installed libraries.
use ./ENV/pip-3.3 install packagename to install at the local environment.
use ./ENV/python3.3 pythonfile.py to run your python script.

Here is my way to solve this problem at ubuntu 12.04:
sudo apt-get install build-essential libncursesw5-dev libssl-dev libgdbm-dev libc6-dev libsqlite3-dev tk-dev
Then install the python3 from source code:
wget https://www.python.org/ftp/python/3.4.0/Python-3.4.0.tar.xz
tar xvf Python-3.4.0.tar.xz
cd Python-3.4.0
./configure
make
make test
sudo make install
When you finished installing all of them, pip3 will get installed automatically.

This is what I did on OS X Mavericks to get this to work.
Firstly, have brew installed
Install python 3.4
brew install python3
Then I get the latest version of distribute:
wget https://pypi.python.org/packages/source/d/distribute/distribute-0.7.3.zip#md5=c6c59594a7b180af57af8a0cc0cf5b4a
unzip distribute-0.7.3.zip
cd distribute-0.7.3
sudo setup.py install
sudo easy_install-3.4 pip
sudo pip3.4 install virtualenv
sudo pip3.4 install virtualenvwrapper
mkvirtualenv py3
python --version
Python 3.4.1
I hope this helps.

pip is installed together when you install Python. You can use
sudo pip install (module)
or
python3 -m pip install (module).

Please follow below steps to install python 3 with pip:
Step 1 : Install Python from download here
Step 2 : you’ll need to download get-pip.py
Step 3 : After download get-pip.py , open your commant prompt and go to directory where your get-pip.py file saved .
Step 4 : Enter command python get-pip.py in cmd.
Step 5 : Pip installed successfully , Verify pip installation by type command in cmd pip --version

What’s New In Python 3.4
...
pip should always be available
...
By default, the commands pipX and pipX.Y will be installed on all platforms (where X.Y stands for the version of the Python installation), along with the pip Python package and its dependencies.
https://docs.python.org/3/whatsnew/3.4.html#whatsnew-pep-453
so if you have python 3.4 installed, you can just: sudo pip3 install xxx

For python3 try this:
wget https://bitbucket.org/pypa/setuptools/raw/bootstrap/ez_setup.py -O - | python
The good thing is that It will also detect what version of python you have (even if it's an environment of python in your custom location).
After this you can proceed normally with (for example)
pip install numpy
source:
https://pypi.python.org/pypi/setuptools/1.1.6#upgrading-from-setuptools-0-6

Assuming you are in a highly restricted computer env (such as myself) without root access or ability to install packages...
I had never setup a fresh/standalone/raw/non-root instance of Python+virtualenv before this post. I had do quite a bit of Googling to make this work.
Decide if you are using python (python2) or python3 and set your PATH correctly. (I am strictly a python3 user.) All commands below can substitute python3 for python if you are python2 user.
wget https://pypi.python.org/packages/source/v/virtualenv/virtualenv-x.y.z.tar.gz
tar -xzvf virtualenv-x.y.z.tar.gz
python3 virtualenv-x.y.z/virtualenv.py --python $(which python3) /path/to/new/virtualenv
source /path/to/new/virtualenv/bin/activate
Assumes you are using a Bourne-compatible shell, e.g., bash
Brilliantly, this virtualenv package includes a standalone version of pip and setuptools that are auto-magically installed into each new virtualenv. This solves the chicken and egg problem.
You may want to create an alias (or update your ~/.bashrc, etc.) for this final command to activate the python virtualenv during each login. It can be a pain to remember all these paths and commands.
Check your version of python now: which python3 should give: /path/to/new/virtualenv/bin/python3
Check pip is also available in the virtualenv via which pip... should give: /path/to/new/virtualenv/bin/pip
Then... pip, pip, pip!
Final tip to newbie Pythoneers: You don't think you need virtualenv when you start, but you will be happy to have it later. Helps with "what if" installation / upgrade scenarios for open source / shared packages.
Ref: https://virtualenv.pypa.io/en/latest/installation.html

To install pip, securely download get-pip.py.
Then run the following:
python get-pip.py
Be cautious if you're using a Python install that's managed by your
operating system or another package manager. get-pip.py does not
coordinate with those tools, and may leave your system in an
inconsistent state.
Refer: PIP Installation

And for Windows 8.1/10 OS Users just open cmd (command prompt)
write this : C:\Users\%USERNAME%\AppData\Local\Programs\Python\Python36-32\Scripts
then
just write this : pip3 install {name of package}
Hint: the location of folder Python36-32 may get different for new python 3.x versions

If you used the command "python get-pip.py", you should have the 'pip' function for Python3. However, 'pip' for Python2 might still be present. In my case I uninstalled 'pip', which removed it from Python2.
After that I ran "python get-pip.py" again. (Make sure that 'get-pip.py' is saved in the same folder as Python3.) The final step was to add the directory with 'pip' command to $PATH. That solved it for me.

=>Easy way to install Python any version on Ubuntu 18.04 or Ubuntu 20.04 follow these steps:-
Step 1: Update Local Repositories:-
sudo apt update
Step 2: Install Supporting Software:-
sudo apt install build-essential zlib1g-dev libncurses5-dev libgdbm-dev libnss3-dev libssl-dev libreadline-dev libffi-dev wget
Step3: Create directory on your home directory To download the newest release of Python Source Code, navigate to the /python-source-files directory and use the wget command:-
mkdir python-source-files
Step 4: Download the Latest Version of Python Source Code:-
wget https://www.python.org/ftp/python/3.7.5/Python-3.7.5.tgz
"you can change python version by just modifies this:-"3.7.5" with the version you want example:-"3.5.2"
Step 5: Extract Compressed Files:-
tar –xf Python-3.7.5.tgz
or
tar xvzf Python-3.7.5.tgz
Step 6: Test System and Optimize Python:-
cd python-3.7.5 or your version of python.
Step 7: Now configure(Using the ––optimization option speeds code execution by 10-20%.):-
./configure ––enable–optimizations
OR you can also do this also if you facing ssl error:-
./configure --with-openssl
Step 8: Install a Second Instance of Python:-
sudo make altinstall
"It is recommended that you use the altinstall method. Your Ubuntu system may have software packages dependent on Python 2.x.
OR
If you want to Overwrite Default Python Installation/version:-
sudo make install"
Step 9:Now check Python Version:-
python3 ––version
Step 10: To install pip for python3 just go with this command:-
sudo apt-get install python3-pip

How to install pip for a specific python version

I have my deployment system running CentOS 6.
It has by default python 2.6.6 installed. So, "which python" gives me /usr/bin/python (which is 2.6.6)
I later installed python3.5, which is invoked as python3 ("which python3" gives me /usr/local/bin/python3)
Using pip, I need to install a few packages that are specific to python3. So I did pip install using:-
"sudo yum install python-pip"
So "which pip" is /usr/bin/pip.
Now whenever I do any "pip install", it just installs it for 2.6.6. :-(
It is clear that pip installation got tied to python 2.6.6 and invoking pip later, only installs packages for 2.6.6.
How can I get around this issue?

If pip isn’t already installed, then first try to bootstrap it from the standard library:
$ python3.5 -m ensurepip --default-pip
If that still doesn’t allow you to run pip:
Securely Download get-pip.py.
Run sudo python3.5 get-pip.py.
Now you can use pip3 to install packages for python3.5. For example, try:
$ sudo pip3 install ipython # isntall IPython for python3.5
Alternatively, as long as the corresponding pip has been installed, you can use pip for a specific Python version like this:
$ python3.5 -m pip install SomePackage # specifically Python 3.5
References:
Ensure you can run pip from the command line
work with multiple versions of Python installed in parallel?

I have python 3.6 and 3.8 on my Ubuntu 18.04 WSL machine. Running
sudo apt-get install python3-pip
pip3 install my_package_name
kept installing packages into Python 3.6 dist directories. The only way that I could install packages for Python 3.8 was:
python3.8 -m pip install my_package_name
That installed appropriate package into the Python 3.8 dist package directory so that when I ran my code with python3.8, the required package was available.

Example of how to install pip for a specific python version
curl https://bootstrap.pypa.io/get-pip.py -o get-pip.py
/opt/local/bin/python2.7 get-pip.py
Script is from official doc: https://pip.pypa.io/en/stable/installing/

On Ubuntu 18.04.1 LTS I wanted to install pip for my second python version (python3) and the following command did the trick for me:
$ sudo apt install python3-pip

How to install pip for Python 2

I run
python --version
and get
Python 2.7.3
I run
pip --version
and get
pip 1.5 from /usr/local/lib/python3.2/dist-packages/pip-1.5-py3.2.egg (python 3.2)
I installed pip using apt-get. How to I get the Python 2 version of pip?
I've reinstalled python and python-pip several times with apt-get. I'm also curious why these would install different Python versions.

To install pip for Python2 on Ubuntu, this worked for me
sudo apt update
curl https://bootstrap.pypa.io/pip/2.7/get-pip.py --output get-pip.py
sudo python2 get-pip.py
It's based on DareDevil7's answer but notice the url is different.

If there are both python2.7 and python3 in you ubuntu system,run this
sudo apt install python-pip
There will be pip for python3 ,pip2 for python2

I would suggest that you use pyenv to manage multiple versions of Python, because it can often get problematic. Right now the solution to the problem would depend on the configuration you have for pip and python in your bash.
One thing you can do is download the easy_install script, and use python 3 to run it and install pip for python 3 alone.

If you really want to install pip globally for your system use the get-pip.py script with the wanted python binary http://www.pip-installer.org/en/latest/installing.html#install-or-upgrade-pip
python2.7 get-pip.py
But you should consider using virtualenv / buildout to get an isolated environment

Download the tar.gz of pip from https://pypi.python.org/pypi/pip#downloads.
Unzip or Untar, Then from its untar directory install for any specific version of python using
python2.7 setup.py install
or
python3.3 setup.py install

Run the following Commands:
sudo add-apt-repository universe
sudo apt update
curl https://bootstrap.pypa.io/get-pip.py --output get-pip.py
sudo python get-pip.py

run this
python2.7 -m ensurepip --upgrade

Its a not a good idea to install pip for python2 system wide. I guess, you need to run a project with python2. The best solution is vritualenv.
I am making an assumption that in your installation which python2 returns /usr/bin/python2.7
1. sudo apt install python2-pip-whl
2. sudo apt install python2-setuptools-whl
3 virtualenv -p /usr/bin/python2.7 YOURPROJECT
4. source YOURPROJECT/bin/activate
The last command will now activate the virtual environment and in this environment, your python is python2.7 and pip is installed for python2.7 as well.
You can deactivate your virtual environment using deactivate.