As @bsipocz asked in #5828 (comment), "I run into this again today, and it seems we can change the config dir, but not the cache dir? If I misunderstand the situation, then we probably need to add more examples to the config dir, one especially for the case of the custom cache dir."

There is an option to change cache directory but has to be via XDG_CACHE_HOME. However, on Linux, changing it affects system-wide setting.

Maybe @bsipocz can clarify if this is a matter of documentation of improving https://docs.astropy.org/en/latest/config/index.html#astropy-config and/or https://docs.astropy.org/en/latest/utils/data.html . Or XDG_CACHE_HOME is simply insufficient.

Might also be relevant:

• Why doesn't astropy use ~/.config/astropy by default (on Unix-like systems)? #6803
• Cache for test files #8748
• Persist astropy cache #9557
• Config woes meta-ticket - add ASTROPY_CONFIG_DIR and ASTROPY_CACHE_DIR #10738
• Let user define cache location #17507

Previous unmerged attempts:

• Allow custom root directory for config/cache #5828
• Allow custom root directory for config #6985