Installed Flask in a virtualenv yet “command not found”

Question

Installed virtualenv, activated it, pip installed flask, and yet, when i try to run a script or see if it recognised, i get command not found.

(project)gabri         


        

Answer 1

Verify where you have installed flask:

mortiz@florida:~/Documents/projects$ pip freeze |grep -i flask
Flask==1.0.2
mortiz@florida:~/Documents/projects$ pip2 freeze |grep -i flask
Flask==1.0.2
mortiz@florida:~/Documents/projects$ pip3 freeze |grep -i flask
Flask==1.0.2
Flask-CLI==0.4.0
Flask-Jsonpify==1.5.0
Flask-RESTful==0.3.6
Flask-SQLAlchemy==2.3.2

Verify you are installing flask for your correct python version inside your virtual environment.

Find out your python version "inside your (venv)"

mortiz@florida:~/Documents/projects/python/APIS/new_project_py_2_7$ which python
    /home/mortiz/Documents/projects/python/APIS/new_project_py_2_7/venv/bin/python

(venv) mortiz@florida:~/Documents/projects/python/APIS/new_project_py_2_7$ python --version
Python 3.5.3

Installation of flask for python3

pip3 install flask
#or
python3 -m pip install flask

Installation of flask for python2

pip2 install flask
#or
python2 -m pip install flask

Installation of flask for default python (be careful if you are inside your (venv) or in your shell)

pip install flask
python -m install flask

Explanation

For people who run higher versions of Flask consider evaluating your environment as explained here.

For me the problem was installing flask for python2 when the binary of my (venv) ran python3.