At the end of my article How to install Anaconda on Ubuntu I verified that Anaconda was installed successfully by executing conda list. You've probably noticed (base) that appears in front of command prompt:
(base) $
This happens after we activate conda by executing ~/.bashrc:
$ cat ~/.bashrc
...
# >>> conda initialize >>>
# !! Contents within this block are managed by 'conda init' !!
__conda_setup="$('/home/bojan/anaconda3/bin/conda' 'shell.bash' 'hook' 2> /dev/null)"
if [ $? -eq 0 ]; then
eval "$__conda_setup"
else
if [ -f "/home/bojan/anaconda3/etc/profile.d/conda.sh" ]; then
. "/home/bojan/anaconda3/etc/profile.d/conda.sh"
else
export PATH="/home/bojan/anaconda3/bin:$PATH"
fi
fi
unset __conda_setup
# <<< conda initialize <<<
...
As conda is also an environment manager it is capable of setting a specified or a default environment.
Each environment has associated:
- name
- collection of packages
- resources which are stored in a dedicated directory
When conda is activated, it sets a default environment unless some other is specified. Its name appears within parentheses before the prompt in terminal. In our case that was a default environment named base.
To list all available environments with their names and associated directories we can use:
$ conda env list
# conda environments:
#
base * /home/bojan/anaconda3
Asterisk (*) appears next to the currently active environment.
Another way to get the same information is:
$ conda info --envs
# conda environments:
#
base * /home/bojan/anaconda3
Here is the content of the base environment directory:
$ ls -1a /home/bojan/anaconda3
.
..
bin
compiler_compat
condabin
conda-meta
doc
envs
etc
include
lib
libexec
LICENSE.txt
man
mkspecs
phrasebooks
pkgs
plugins
qml
resources
sbin
share
shell
ssl
translations
var
x86_64-conda_cos6-linux-gnu
To deactivate the current environment:
(base) $ conda deactivate
$
To activate default environment again:
$ conda activate
(base) $
After installing Conda, base environment is set to be auto activated by default:
(base) $ conda config --show | grep auto_activate_base
auto_activate_base: True
To turn this off we need to set that flag to False (bash - How to remove (base) from terminal prompt after updating conda - Stack Overflow):
(base) $ conda config --set auto_activate_base False
Let's verify it:
(base) $ conda config --show | grep auto_activate_base
auto_activate_base: False
Next time we open a new terminal, we should not see (base) in front of the prompt.
Note that when we have a base environment activated, Terminal shell uses Python from Anaconda installaton:
(base) $ which python
/home/bojan/anaconda3/bin/python
(base) $ which python3
/home/bojan/anaconda3/bin/python3
When no environment is activated, Terminal shell uses Python from a system installation:
$ which python
/usr/bin/python
$ which python3
/usr/bin/python3
Same applies to pip and pip3:
(base) $ which pip
/home/bojan/anaconda3/bin/pip
(base) $ which pip3
/home/bojan/anaconda3/bin/pip3
$ which pip
/home/bojan/.local/bin/pip
$ which pip3
/home/bojan/.local/bin/pip3
Each environment can be specified with its YAML (.yml) file. This file contains all necessary information for conda to recreate the same environment on some other computer:
- name
- channels
- dependencies
Environment yaml file generic example:
name: my_env
channels:
- channel1
dependencies:
- python=3.6
- some_package=1.2 # it is possible to add comments
- some_package2
- jupyter=1.0.0
- jupyterlab=0.34.9
- keras=2.2.2=0
- matplotlib=2.2.3
- ...
We can create this yaml file manually or can use conda command:
$ conda env export > my_environment.yml
To re-create the environment from a given yaml file:
$ conda env create -f my_environment.yml
Collecting package metadata (repodata.json): done
Solving environment: done
==> WARNING: A newer version of conda exists. <==
current version: 4.8.3
latest version: 4.8.5
Please update conda by running
$ conda update -n base -c defaults conda
Downloading and Extracting Packages
gmp-6.1.2 | 751 KB | ##################################### | 100%
prometheus_client-0. | 44 KB | ##################################### | 100%
libstdcxx-ng-9.3.0 | 4.0 MB | ##################################### | 100%
defusedxml-0.6.0 | 22 KB | ##################################### | 100%
ipython-7.16.1 | 1.1 MB | ##################################### | 100%
kiwisolver-1.2.0 | 87 KB | ##################################### | 100%
libgcc-ng-9.3.0 | 7.8 MB | ##################################### | 100%
...
Preparing transaction: done
Verifying transaction: done
Executing transaction: \ b'Enabling notebook extension jupyter-js-widgets/extension...\n - Validating: \x1b[32mOK\x1b[0m\n'
done
#
# To activate this environment, use
#
# $ conda activate my_environment
#
# To deactivate an active environment, use
#
# $ conda deactivate
We can verify that this environment has now been added to conda:
(base) $ conda env list
# conda environments:
#
base * /home/bojan/anaconda3
my_environment /home/bojan/anaconda3/envs/my_environment
test-opencv /home/bojan/anaconda3/envs/test-opencv
To activate this environment:
(base)$ conda activate my_environment
(my_environment)$
To check which packages are installed in the current environment:
(my_environment) $ conda list
# packages in environment at /home/bojan/anaconda3/envs/my_environment:
#
# Name Version Build Channel
_libgcc_mutex 0.1 conda_forge conda-forge
_openmp_mutex 4.5 1_gnu conda-forge
absl-py 0.10.0 py36h9f0ad1d_0 conda-forge
argon2-cffi 20.1.0 py36h8c4c3a4_1 conda-forge
astor 0.8.1 pyh9f0ad1d_0 conda-forge
async_generator 1.10 py_0 conda-forge
atk 2.25.90 hf2eb9ee_1001 conda-forge
attrs 20.2.0 pyh9f0ad1d_0 conda-forge
backcall 0.2.0 pyh9f0ad1d_0 conda-forge
backports 1.0 py_2 conda-forge
...
To install additional package to the current environment:
(my_environment) $ conda install pillow
Collecting package metadata (current_repodata.json): done
Solving environment: done
## Package Plan ##
environment location: /home/bojan/anaconda3/envs/my_environment
added / updated specs:
- pillow
The following packages will be downloaded:
package | build
---------------------------|-----------------
ca-certificates-2020.10.14 | 0 121 KB
certifi-2020.6.20 | py36_0 156 KB
olefile-0.46 | py36_0 48 KB
openssl-1.0.2u | h7b6447c_0 2.2 MB
pillow-7.2.0 | py36hb39fc2d_0 619 KB
------------------------------------------------------------
Total: 3.1 MB
The following NEW packages will be INSTALLED:
lcms2 pkgs/main/linux-64::lcms2-2.11-h396b838_0
olefile pkgs/main/linux-64::olefile-0.46-py36_0
pillow pkgs/main/linux-64::pillow-7.2.0-py36hb39fc2d_0
The following packages will be UPDATED:
ca-certificates conda-forge::ca-certificates-2020.6.2~ --> pkgs/main::ca-certificates-2020.10.14-0
The following packages will be SUPERSEDED by a higher-priority channel:
certifi conda-forge::certifi-2020.6.20-py36h9~ --> pkgs/main::certifi-2020.6.20-py36_0
openssl conda-forge::openssl-1.0.2u-h516909a_0 --> pkgs/main::openssl-1.0.2u-h7b6447c_0
Proceed ([y]/n)? y
Downloading and Extracting Packages
openssl-1.0.2u | 2.2 MB | ################################################################ | 100%
certifi-2020.6.20 | 156 KB | ################################################################ | 100%
pillow-7.2.0 | 619 KB | ################################################################ | 100%
ca-certificates-2020 | 121 KB | ################################################################ | 100%
olefile-0.46 | 48 KB | ################################################################ | 100%
Preparing transaction: done
Verifying transaction: done
Executing transaction: done
We can verify that a new package is indeed installed in new environment:
(my_environment) $ conda list
# packages in environment at /home/bojan/anaconda3/envs/my_environment:
#
# Name Version Build Channel
...
pillow 7.2.0 py36hb39fc2d_0
...
To install a new package from a specific channel in the current environment:
(my_environment) $ conda install -c channel_name package_name
To install a specific version of a new package from a specific channel in the current environment:
(my_environment) $ conda install -c channel_name package_name=version
To uninstall some package from the current environment:
(my_environment) $ conda remove pillow
To uninstall multiple packages from the current environment:
(my_environment) $ conda remove package1 package2 ...
To update conda (I've deactivated the current environment):
$ conda update -n base -c defaults conda
Collecting package metadata (current_repodata.json): done
Solving environment: done
## Package Plan ##
environment location: /home/bojan/anaconda3
added / updated specs:
- conda
The following packages will be downloaded:
package | build
---------------------------|-----------------
conda-4.8.5 | py38_0 2.9 MB
------------------------------------------------------------
Total: 2.9 MB
The following packages will be UPDATED:
conda 4.8.3-py38_0 --> 4.8.5-py38_0
Proceed ([y]/n)? y
Downloading and Extracting Packages
conda-4.8.5 | 2.9 MB | ################################################################################################################################################################# | 100%
Preparing transaction: done
Verifying transaction: done
Executing transaction: done
To remove given environment:
$ conda env remove --name test-opencv
Remove all packages in environment /home/bojan/anaconda3/envs/test-opencv:
We can verify that its directory does not exist:
$ ls /home/bojan/anaconda3/envs/test-opencv
ls: cannot access '/home/bojan/anaconda3/envs/test-opencv': No such file or directory
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