607
votes

I've come across situations where a current version of a package seems not to be working and requires reinstallation. But pip install -U won't touch a package that is already up-to-date. I see how to force a reinstallation by first uninstalling (with pip uninstall) and then installing, but is there a way to simply force an "update" to a nominally current version in a single step?

7
for those looking to re-install pip it self (if it stopped working for some reason ;) ), the answer can be found in this SO q&ansof

7 Answers

907
votes
pip install --upgrade --force-reinstall <package>

When upgrading, reinstall all packages even if they are already up-to-date.

pip install -I <package>
pip install --ignore-installed <package>

Ignore the installed packages (reinstalling instead).

221
votes

You might want to have all three options: --upgrade and --force-reinstall ensures reinstallation, while --no-deps avoids reinstalling dependencies.

$ sudo pip install --upgrade --no-deps --force-reinstall <packagename>

Otherwise you might run into the problem that pip starts to recompile Numpy or other large packages.

38
votes

If you want to reinstall packages specified in a requirements.txt file, without upgrading, so just reinstall the specific versions specified in the requirements.txt file:

pip install -r requirements.txt --ignore-installed
35
votes
--force-reinstall

doesn't appear to force reinstall using python2.7 with pip-1.5

I've had to use

--no-deps --ignore-installed
10
votes
sudo pip3 install --upgrade --force-reinstall --no-deps --no-cache-dir <package-name>==<package-version>

Some relevant answers:

Difference between pip install options "ignore-installed" and "force-reinstall"

7
votes

If you have a text file with loads of packages you need to add the -r flag

pip install --upgrade --no-deps --force-reinstall -r requirements.txt
7
votes

In the case you need to force the reinstallation of pip itself you can do:

python -m pip install --upgrade --force-reinstall pip