Here's how to create a Nix binary cache from a derivation's closure within a Nix derivation. Since you can't run nix commands within derivations, this can be useful for including a build closure within an installation medium, such as when performing a NixOS offline installation.
I'm currently renewing my visa (residence permit, 在留許可) in Japan. While I've submitted my application 3 months ahead of its expiry, the Immigration Services Agency (出入国在留管理庁) appears to be overwhelmed with applications.
Do you loathe online banking as much as I do? Does your bank make online banking more cumbersome each week in the name of "combating fraud" and "staying compliant" with anti-money laundering and counter terrorist financing laws? Have you ever looked under online banking's hood? Here's an example from a bank that I use in Japan to pay for life necessities and to keep a roof over my head.