def _python_cmd(env):
    anaconda_py = os.path.join(env.system_install, "anaconda", "bin", "python")
    if env.safe_exists(anaconda_py):
        return anaconda_py
    if "python_version_ext" in env and env.python_version_ext:
        major, minor = env.safe_run("python --version").split()[-1].split(".")[:2]
        check_major, check_minor = env.python_version_ext.split(".")[:2]
        if major != check_major or int(check_minor) > int(minor):
            return "python%s" % env.python_version_ext
        else:
            return "python"
    else:
        return "python"
Retrieve python command, handling tricky situations on CentOS.
dataset/ETHPy150Open chapmanb/cloudbiolinux/cloudbio/custom/shared.py/_python_cmd