1. CommandNotFoundError when conda uses the conda deactivate command

codedancing@Ubuntu:/usr/local/anaconda3$ conda deactivate

CommandNotFoundError: Your shell has not been properly configured to use 'conda deactivate'.
To initialize your shell, run

    $ conda init <SHELL_NAME>

Currently supported shells are:
  - bash
  - fish
  - tcsh
  - xonsh
  - zsh
  - powershell

See 'conda init --help' for more information and options.

IMPORTANT: You may need to close and restart your shell after running 'conda init'.

Solve:
You need to enter source activate to activate the environment

1. When using conda to create a new virtual environment of python3.6, we encountered configuration residual problems. Print the information:

(base) codedancing@Ubuntu:~$ conda create --name python3.6 python=3.6

Collecting package metadata (current_repodata.json): done
Solving environment: done


==> WARNING: A newer version of conda exists. <==
  current version: 4.7.12
  latest version: 4.8.1

Please update conda by running

    $ conda update -n base -c defaults conda



## Package Plan ##

  environment location: /usr/local/anaconda3/envs/python3.6

  added / updated specs:
    - python=3.6


The following packages will be downloaded:

    package                    |            build
    ---------------------------|-----------------
    ca-certificates-2019.11.27 |                0         124 KB
    certifi-2019.11.28         |           py36_0         153 KB
    ld_impl_linux-64-2.33.1    |       h53a641e_7         568 KB
    openssl-1.1.1d             |       h7b6447c_3         2.5 MB
    pip-19.3.1                 |           py36_0         1.7 MB
    python-3.6.10              |       h0371630_0        29.7 MB
    setuptools-44.0.0          |           py36_0         510 KB
    sqlite-3.30.1              |       h7b6447c_0         1.1 MB
    wheel-0.33.6               |           py36_0          42 KB
    ------------------------------------------------------------
                                           Total:        36.3 MB

The following NEW packages will be INSTALLED:

  _libgcc_mutex      pkgs/main/linux-64::_libgcc_mutex-0.1-main
  ca-certificates    pkgs/main/linux-64::ca-certificates-2019.11.27-0
  certifi            pkgs/main/linux-64::certifi-2019.11.28-py36_0
  ld_impl_linux-64   pkgs/main/linux-64::ld_impl_linux-64-2.33.1-h53a641e_7
  libedit            pkgs/main/linux-64::libedit-3.1.20181209-hc058e9b_0
  libffi             pkgs/main/linux-64::libffi-3.2.1-hd88cf55_4
  libgcc-ng          pkgs/main/linux-64::libgcc-ng-9.1.0-hdf63c60_0
  libstdcxx-ng       pkgs/main/linux-64::libstdcxx-ng-9.1.0-hdf63c60_0
  ncurses            pkgs/main/linux-64::ncurses-6.1-he6710b0_1
  openssl            pkgs/main/linux-64::openssl-1.1.1d-h7b6447c_3
  pip                pkgs/main/linux-64::pip-19.3.1-py36_0
  python             pkgs/main/linux-64::python-3.6.10-h0371630_0
  readline           pkgs/main/linux-64::readline-7.0-h7b6447c_5
  setuptools         pkgs/main/linux-64::setuptools-44.0.0-py36_0
  sqlite             pkgs/main/linux-64::sqlite-3.30.1-h7b6447c_0
  tk                 pkgs/main/linux-64::tk-8.6.8-hbc83047_0
  wheel              pkgs/main/linux-64::wheel-0.33.6-py36_0
  xz                 pkgs/main/linux-64::xz-5.2.4-h14c3975_4
  zlib               pkgs/main/linux-64::zlib-1.2.11-h7b6447c_3


Proceed ([y]/n)? y


Downloading and Extracting Packages
certifi-2019.11.28   | 153 KB    | ######################################################### | 100% 
sqlite-3.30.1        | 1.1 MB    | ######################################################### | 100% 
setuptools-44.0.0    | 510 KB    | ######################################################### | 100% 
ld_impl_linux-64-2.3 | 568 KB    | ######################################################### | 100% 
pip-19.3.1           | 1.7 MB    | ######################################################### | 100% 
ca-certificates-2019 | 124 KB    | ######################################################### | 100% 
wheel-0.33.6         | 42 KB     | ######################################################### | 100% 
openssl-1.1.1d       | 2.5 MB    | ######################################################### | 100% 
python-3.6.10        | 29.7 MB   | ######################################################### | 100% 
Preparing transaction: done
Verifying transaction: / WARNING conda.core.path_actions:verify(963): Unable to create environments file. Path not writable.
  environment location: /home/codedancing/.conda/environments.txt

done
Executing transaction: \ WARNING conda.core.envs_manager:register_env(52): Unable to register environment. Path not writable or missing.
  environment location: /usr/local/anaconda3/envs/python3.6
  registry file: /home/codedancing/.conda/environments.txt
done
#
# To activate this environment, use
#
#     $ conda activate python3.6
#
# To deactivate an active environment, use
#
#     $ conda deactivate

(base) codedancing@Ubuntu:/usr/local/anaconda3$

Question:
Preparing transaction: done Verifying transaction: / WARNING conda.core.path_actions:verify(963): Unable to create environments file. Path not writable. environment location: /home/codedancing/.conda/environments.txt

Executing transaction: \ WARNING conda.core.envs_manager:register_env(52): Unable to register environment. Path not writable or missing. environment location: /usr/local/anaconda3/envs/python3.6 registry file: /home/codedancing/.conda/environments.txt

Reason:
Users of the system have previously installed conda environment as an administrator, and need to delete ~ /. conda and ~ /. condarc files under the user's home directory
Use conda remove -n python3.6 --all to remove the virtual environment with installation problems and reinstall