I've recently switched over to using the fantastic autoenv to automatically activate my anaconda environments and set necessary environment variables when I enter a directory on my terminal. You basically write some bash code in a .env file, put it into a directory, and autoenv will automatically run .env when you enter the directory or any of its subdirectories.
However, I found that putting just source activate desired_environment in my .env (to activate the desired_environment conda environment) made my shell very slow --- I'd have to wait ~2 seconds after issuing a cd into a directory with a .env file (or a subdirectory of one).
The following bash snippet makes activating conda environments with autoenv a lot faster:
current_environment=""
environment_to_activate=test
# $CONDA_PREFIX is non-empty when in an environment
if [[ $CONDA_PREFIX != "" ]]; then
# Get the name of the environment from the path
current_environment="${CONDA_PREFIX##*/}"
fi
if [[ $current_environment != $environment_to_activate ]]; then
# We are not in the environment to activate, so activate it.
source activate $environment_to_activate
fi
The snippet basically checks if you're already in the conda environment you want to activate (called test in this case, and assigned to environment_to_activate), and doesn't rerun the slow activate script if you are. Handy!
To use this snippet, just drop it into your .env file and replace test with the name of whatever environment you want to activate; your shell should feel a lot less slow.