I have tried this you solution but it did not work.
For Step 1: I run this command to see where pip is located on the system
frappe@erp:~$ pip show pip
Name: pip
Version: 9.0.1
Summary: The PyPA recommended tool for installing Python packages.
Home-page: https://pip.pypa.io/
Author: The pip developers
Author-email: python-virtualenv@groups.google.com
License: MIT
Location: /usr/local/lib/python2.7/dist-packages
Requires:
Then this to for update: pip install pip --upgrade
frappe@erp:~$ pip install pip --upgrade
/usr/local/lib/python2.7/dist-packages/pip/_vendor/requests/packages/urllib3/util/ssl_.py:318: SNIMissingWarning: An HTTPS request has been made, but the SNI (Subject Name Indication) extension to TLS is not available on this platform. This may cause the server to present an incorrect TLS certificate, which can cause validation failures. You can upgrade to a newer version of Python to solve this. For more information, see https://urllib3.readthedocs.io/en/latest/security.html#snimissingwarning.
SNIMissingWarning
/usr/local/lib/python2.7/dist-packages/pip/_vendor/requests/packages/urllib3/util/ssl_.py:122: InsecurePlatformWarning: A true SSLContext object is not available. This prevents urllib3 from configuring SSL appropriately and may cause certain SSL connections to fail. You can upgrade to a newer version of Python to solve this. For more information, see https://urllib3.readthedocs.io/en/latest/security.html#insecureplatformwarning.
InsecurePlatformWarning
Requirement already up-to-date: pip in /usr/local/lib/python2.7/dist-packages
STEP 2: Frappe-bench Directory Python Virtual
frappe@erp:~/frappe-bench$ ./env/bin/pip install pip --upgrade
bash: ./env/bin/pip: No such file or directory
Actually the pip fill is missing on the /home/frappe/frappe-bench/env/bin/