name: eval-system internalName: currentSystem type: std::string default: ''

This option defines builtins.currentSystem in the Nix language if it is set as a non-empty string. Otherwise, if it is defined as the empty string (the default), the value of the system configuration setting is used instead.

Unlike system, this setting does not change what kind of derivations can be built locally. This is useful for evaluating Nix code on one system to produce derivations to be built on another type of system.