/bin/sh: 1: flask: not found

[greatidea1]

Requested Werkzeug>=2.0 from https://files.pythonhosted.org/packages/83/3c/ecdb36f49ab06defb0d5a466cfeb4ae90a55d02cfef379f781da2801a45d/Werkzeug-2.0.2.tar.gz#sha256=aa2bb6fc8dee8d6c504c0ac1e7f5f7dc5810a9903e793b6f715a9f015bdadb9a (from flask), but installing version None

Requested itsdangerous>=2.0 from https://files.pythonhosted.org/packages/58/66/d6c5859dcac92b442626427a8c7a42322068c5cd5d4a463ce78b93f730b7/itsdangerous-2.0.1.tar.gz#sha256=9e724d68fc22902a1435351f84c3fb8623f303fffcc566a4cb952df8c572cff0 (from flask), but installing version None

Requested itsdangerous>=2.0 from https://files.pythonhosted.org/packages/58/66/d6c5859dcac92b442626427a8c7a42322068c5cd5d4a463ce78b93f730b7/itsdangerous-2.0.1.tar.gz#sha256=9e724d68fc22902a1435351f84c3fb8623f303fffcc566a4cb952df8c572cff0 (from flask), but installing version None

[greatidea1]

Not working, it just says flask not found

[CMapara]

run apt-get update when you first install ubuntu. When you have a freshly installed Ubuntu system, the cache is empty. This is why you should run the apt update command right after installing Ubuntu or any other distributions based on Ubuntu.