cache-directory-use-xdg-cache-home

Cache directory: use $XDG_CACHE_HOME

We prefer to have a user's cache directory in a standard place:

• Use XDG_CACHE_HOME environment variable if it's set.
• Otherwise use $HOME/.cache.
• Append the program command, so the program uses its own subdirectory.

Code:

cache_home() { out "${XDG_CACHE_HOME:-$HOME/.cache}" ; }; export -f cache_home;
cache_dir() { out $(cache_home)"/$program_command" ; };

References:

• https://wiki.archlinux.org/index.php/XDG_Base_Directory_support

Purpose:

• Where user-specific non-essential (cached) data should be written (analogous to /var/cache).
• Should default to $HOME/.cache.