Quickly Change Conda Env With Fzf

Waylon Walker

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}')"
}

reusable-bash

for more information on writing reusable bash scripts check out one of my favorite articles

I am always on the lookout for cool new use cases for fzf, if you have one please share it with me.