Tested on Ubuntu 20.04:
mkdir -p ~/miniconda3
wget https://repo.anaconda.com/miniconda/Miniconda3-py311_23.11.0-2-Linux-x86_64.sh -O ~/miniconda3/miniconda.sh
bash ~/miniconda3/miniconda.sh -b -u -p ~/miniconda3
rm -rf ~/miniconda3/miniconda.sh
~/miniconda3/bin/conda init bash
. ~/.bashrc
and from then on we can do conda commands normally.
At that time, the exact installer under latest appears to have been: repo.anaconda.com/miniconda/Miniconda3-py311_23.11.0-2-Linux-x86_64.sh