conda activate command not working on mac - macos

Question

I have miniconda 4.8.3 + MacOS Catalina 10.15. I can manually activate the conda environment in the terminal and start a spyder session.
$ ~/miniconda3/bin/conda activate py3
$ ~/miniconda3/bin/conda info | grep "active environment"
$ spyder &
When I put the above in a script, run_spyder.sh it's not working, and it complains about "CommandNotFoundError: Your shell has not been properly configured to use 'conda activate'."
#!/bin/bash
# run_spyder.sh
~/miniconda3/bin/conda activate py3
~/miniconda3/bin/conda info | grep "active environment" # still print base
# spyder &
I tried alternatives like bash -i ./run_spyder.sh, or source ./run_spyder.sh, or adding ~/miniconda3/bin/conda init bash, none of them work.
Shell is still bash, no .bashrc, in .bash_profile this is the script automatically generated by miniconda installation
# .bashrc_profile
# >>> conda initialize >>>
# !! Contents within this block are managed by 'conda init' !!
__conda_setup="$('~/miniconda3/bin/conda' 'shell.bash' 'hook' 2> /dev/null)"
if [ $? -eq 0 ]; then
eval "$__conda_setup"
else
if [ -f "~/miniconda3/etc/profile.d/conda.sh" ]; then
. "~/miniconda3/etc/profile.d/conda.sh"
else
export PATH="~/miniconda3/bin:$PATH"
fi
fi
unset __conda_setup
# <<< conda initialize <<<

Answer 1

The conda activate function is a shell function that is typically defined in the initialization file for a shell when the session starts (e.g., in the .bash_profile). The conda init function merely adds code to such initialization files, but will not actually source the code it adds. Hopefully, that clarifies the difficulty with what was tried in the question (and comments).
Instead, try directly sourcing the code that Conda uses. Something like:
#!/bin/bash
source ~/miniconda3/etc/profile.d/conda.sh
conda activate py3
conda info | grep "active environment"
spyder &
Another option is to have the bash (or zsh) session launch in login mode (i.e., runs the initialization files for the current user).
#!/usr/bin/env bash -l
conda deactivate # <- may not be needed, but didn't work for me without
conda activate py3
conda info | grep "active environment"
spyder &
However, note that in this latter case I find I need to include a conda deactivate first, in order for the conda activate to properly prioritize the Python in the env on PATH.