arguments to freeze are used to filter installed packages

[AvdN]

Any arguments to the freeze command used to be discarded. That makes freeze less useful in finding which versions of a few specific packages you have installed, especially if the list is long.

This change makes pip freeze only output that have an argument as part of the package name so you can do:
pip freeze xl pymongo
and get
openpyxl==1.6.1
pymongo==2.5
xlrd==0.9.0
xlutils==1.5.2
xlwt==0.7.4
and not a list of 158 packages. The comparison is done lowercase.

You can of course pipe the output of pip freeze through fgrep , but especially when trying to select multiple patterns in one go, that is not trivial.

[pnasrat]

This needs tests and documentation updates before considering.

I'd also probably argue that we'd want it to be pip freeze --match rather than defaulting to a fuzzy match based on the args.

@qwcode any strong opinion from you on this?

[qwcode]

not sure, I'm just focused on what's tagged for 1.4 right now, which is mostly about wheel.

[msabramo]

Note that #2234 implements this as well (and does a bunch of other cool stuff).

$ pip freeze pytest pytest-cache
pytest==2.6.4
pytest-cache==1.0

[msabramo]

I'd suggest closing in favor of #2234