I was working on a personal Machine learning project for which I was using Anaconda environment with python 2.7(yes I know) because of some dependencies.
I was trying to upgrade the sklearn library and I accidentally updated Python to 3.6. I was about to delete my whole environment and recreate it again from YAML file(thank god I had that), but then I referred conda documentation and there it was, the magic command to save me from all this trouble.
# List the history of each change to the current environment conda list --revisions
# Restore environment to a previous revision conda install --revision 2
The best way to explain is by a quick example. If you run _conda list –revision_, you’ll get an output like this:
2017-04-18 23:29:36 (rev 1) requests {2.12.3 -> 2.13.0}2018-05-30 19:41:47 (rev 2) mkl {11.3.3 -> 2018.0.2} numpy {1.11.2 -> 1.14.3} pip {9.0.1 -> 10.0.1} python {2.7.12 -> 3.6.5} scikit-learn {0.17.1 -> 0.19.1} scipy {0.18.1 -> 1.1.0} setuptools {27.2.0 -> 39.1.0} wheel {0.29.0 -> 0.31.1} +blas-1.0 +certifi-2018.4.16 +icc_rt-2017.0.4 +intel-openmp-2018.0.0 +mkl_fft-1.0.1 +mkl_random-1.0.1 +numpy-base-1.14.3 +vc-14 +vs2015_runtime-14.0.25123 +wincertstore-0.2
As you can see in the output that it list each revision along with updated packages(old version -> new version) and newly added packages(the one with a + symbol). So now you know what changes were make in each revision, you can safely rollback to the previous versions of your environment by using conda install –revision _revision number_.
In my case, I reverted to rev 1, so after rollback when I run _conda list –revisions_ again, I can see the changes done in rollback.
2018-05-30 20:08:46 (rev 3) mkl {2018.0.2 -> 11.3.3} numpy {1.14.3 -> 1.11.2} pip {10.0.1 -> 9.0.1} python {3.6.5 -> 2.7.12} scikit-learn {0.19.1 -> 0.17.1} scipy {1.1.0 -> 0.18.1} setuptools {39.1.0 -> 27.2.0} wheel {0.31.1 -> 0.29.0} -blas-1.0 -certifi-2018.4.16 -icc_rt-2017.0.4 -intel-openmp-2018.0.0 -mkl_fft-1.0.1 -mkl_random-1.0.1 -numpy-base-1.14.3 -vc-14 -vs2015_runtime-14.0.25123 -wincertstore-0.2
You can see that the changes for revision 3 are just the inverse of revision 2.
This comes handy if you accidentally screw up your environment.
More info:
Conda User Guide: https://conda.io/docs/user-guide/tasks/manage-environments.html
Conda Cheat Sheet: https://conda.io/docs/_downloads/conda-cheatsheet.pdf
If you have any suggestions let me know on twitter: @Sriramjaju
Namaste!