$ poetry cache clear --all       

Not enough arguments (missing: "cache")

$ poetry cache clear _default_cache

Add the --all option if you want to clear all _default_cache caches

cache-dir = "/home/paul/.cache/pypoetry"
experimental.system-git-client = false
installer.max-workers = null
installer.modern-installation = true
installer.no-binary = null
installer.parallel = true
keyring.enabled = true
solver.lazy-wheel = true
virtualenvs.create = true
virtualenvs.in-project = true
virtualenvs.options.always-copy = false
virtualenvs.options.no-pip = false
virtualenvs.options.no-setuptools = false
virtualenvs.options.system-site-packages = false
virtualenvs.path = "{cache-dir}/virtualenvs"  # /home/paul/.cache/pypoetry/virtualenvs
virtualenvs.prefer-active-python = false
virtualenvs.prompt = "{project_name}-py{python_version}"
warnings.export = true

$ poetry -vvv cache clear --all

Not enough arguments (missing: "cache")