Anaconda Python 3

One of the easiest ways to install a Python 3 distribution for iSpec on Linux without root permissions is by using Anaconda.

• Go to the Anaconda Python 3 Distribution site (you can Skip registration), pick Distribution Installer for Linux, download the 64-Bit Installer and run it from a terminal (adapt the file name to the downloaded version):

bash Anaconda3-2025.06-0-Linux-x86_64.sh

Follow the instructions, anaconda will be installed in /home/your_user/anaconda3/ by default. The installer will ask if you want to initialize/modify .bashrc or .bash_profile, select 'yes'. The installer should have added to your .bashrc or .bash_profile files (in your home directory) something like this:

# >>> conda initialize >>>
# !! Contents within this block are managed by 'conda init' !!
__conda_setup="$('/home/your_user/anaconda3/bin/conda' 'shell.bash' 'hook' 2> /dev/null)"
if [ $? -eq 0 ]; then
    eval "$__conda_setup"
else
    if [ -f "/home/your_user/anaconda3/etc/profile.d/conda.sh" ]; then
        . "/home/your_user/anaconda3/etc/profile.d/conda.sh"
    else
        export PATH="/home/your_user/anaconda3/bin:$PATH"
    fi
fi
unset __conda_setup
# <<< conda initialize <<<

This will activate anaconda automatically every time you open a terminal.

• Close all the terminals and open a new one in order to re-load this new setup.

• Install a library that does not come by default and that it is needed by iSpec:

conda update conda
conda update --all
conda install lockfile cython
conda install -c conda-forge libgfortran=3 # required library by SME, which is obsolete in modern Linux distributions

• On Debian based GNU/Linux distributions such as Ubuntu or Linux Mint, the following packages should be installed by using the package manager (e.g. sudo apt install package_name) and its the only step that requires root permissions (fortunately, many servers already include these tools):

sudo apt install build-essential gfortran

• Finally, download iSpec source code, decompress it and move to $HOME/iSpec/. Open a terminal in the iSpec directory and run:

make clean
make spectrum
make turbospectrum
make moog