pip freeze --local | grep -v '^\-e' | cut -d = -f 1 | xargs -n1 pip install -U
J'ai fait un alias dans ''~/.bash_aliases'' :
alias pip-up="pip freeze --local | grep -v '^\-e' | cut -d = -f 1 | xargs -n1 pip install -U"
(Ne pas oublier de relancer ''source ~/.bashrc'').
__Source:__ https://stackoverflow.com/questions/2720014/upgrading-all-packages-with-pip