Right now you can use -cat option with add action, but for instance I often need to remove categories from articles in certain category (to prevent duplicities in cat hiearchy), but I cant target a specific category.

Example of future usage:
Article is in categories category X and subcat of category X, which makes having article categorized in category X unnecesary.

I would like to run something like

category.py remove -cat:"subcat of category X" "category X".

which would remove category X from articles categorized in subcat of category X.

Right now I can do that with replace.py, but since we have this nice category.py script it would be great to use it this way.