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

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.

It seems python3-pip is not installed correctly on my system so I did

sudo apt install --reinstall python3-pip

Now I can install programs with pip3.

Check if pip3 is already installed

pip3 -v

if it is installed the output should be like that

C:\Python38\python.exe -m pip <command> [options]

Commands:

  install      Install packages.

  download                    Download packages.

  uninstall                   Uninstall packages.

  freeze                      Output installed packages in requirements format.

  list                        List installed packages.

  show                        Show information about installed packages.

  ...

  ...

Pip3 Upgrade

python -m pip3 install --upgrade pip

Pip3 Downgrade

python -m pip3 install pip==19.0

Ubuntu has pip available in the packages python3-pip for python3 or python-pip for python2.

On Windows pip3 should be in the Scripts path of your Python installation:

C:\path\to\python\Scripts\pip3

Use:

where python

to find out where your Python executable(s) is/are located. The result should look like this:

C:\path\to\python\python.exe

or:

C:\path\to\python\python3.exe

You can check if pip3 works with this absolute path:

C:\path\to\python\Scripts\pip3

if yes, add C:\path\to\python\Scripts to your environmental variable PATH .

The first procedure you followed is correct

sudo apt-get -y install python3-pip

But before installing try to update using command

sudo apt-get update

If first did not work then you can also do this using curl

curl "https://bootstrap.pypa.io/get-pip.py" -o "get-pip.py"
python3 get-pip.py --user

Then to verify installation try

pip3 --help 

For checking version :

pip3 --version