Changing conda environments is a bit verbose, I use a function with fzf that both lists environments and selects the one I want in one go.
Conda
I have used conda as a virtual environment tool for years now. I started using conda for its simplicity to install packages on windows, but now that has gotten so much better and it's been years since I have run a conda install command. I'm sure that I could use a different environment manager, but it works for me and makes sense.
What environment manager do you use for python?
Conda environments are stored in a central location such as ~/miniconda3/envs/ and not with the project. They contain both the python interpreter and packages for that env.
Conda create
Conda environments are created with the conda create command. At this point, you will need to name your env and select the python version.
conda create -n my_env python=3.8
After running this command you will have a directory ~/miniconda3/envs/my_env with a base python install. It will not be active yet.
List environments
Before activating an environment I often want to list the environments that I have installed which are often upwards of 70, so it's hard to remember them all.
conda info --envs
After running this command you will see something like the following.
# conda environments:
#
base /home/waylon/miniconda3
my_env /home/waylon/my_env
Activating an environment
Activating a conda environment will do some magic to your current shells $PATH variable to ensure that the environment that you select is preferred over the base environment.
conda activate my_env
Ready to work
Now you can install packages for your project in an isolated environment safe from wrecking another project or being wrecked by another project.
pip install -r requirements.txt
Using fzf
a bit less verbose
fzf is an amazing tool for the terminal that is a generic fuzzy matcher. It is super performant and can handle insane amounts of text and is brilliant at figuring out what you mean with just a few characters. We can use it here to list out all of our conda environments and select the one we want to activate with just a few keystrokes.
Selecting the environment.
Piping our list of environments directly into fzf gives us a fuzzy selection where we can type a few characters and it will return the row we were looking for.
conda info --envs | fzf
This returns us something like this which also includes the path where it is located.
my_env /home/walkews/miniconda3/envs/my_env
getting just the environment name
To get just the name without the path I pipe the output into awk. There are many ways to do this in bash, this is the way that worked for me at the time I made this function.
conda info --envs | fzf | awk '{print $1}'
Time to activate
Functions that use fzf can be a bit odd, running them in a subshell with the $() syntax generally makes it super simple to utilize the output. No matter how many times I have tried without running it in a subshell it's always buggy without it.
conda activate "$(conda info --envs | fzf | awk '{print $1}')"
This will now run conda activate on the environment that we select with fzf.
Make it a function
We don't want to type that out every time we want to activate an environment. I keep a function called a in my ~/.bashrc and ~/.zshrc so that I can activate an environment with a single character. Yes, I switch environments often enough to justify the valuable namespace of a single character.
a () {
conda activate "$(conda info --envs | fzf | awk '{print $1}')"
}
For more information on writing reusable bash check out one of my favorite articles I have done Creating Reusable Bash Scripts
I am always on the lookout for cool new use cases for fzf, if you have one please share it with me.