nixos-option:tldr:62676
This command is using the "nixos-option" tool to retrieve the value of the option "users.users.${user}" in the NixOS configuration.
In NixOS, the system configuration is described by a set of options. These options are organized in a tree-like structure, where each node represents a group of related options. The "users" option represents the user accounts configured on the system.
The command uses the variable "${user}" as a placeholder for the specific username you want to query. By using the "-r" option, the command specifies that the value should be read from the active NixOS configuration (usually located at "/etc/nixos/configuration.nix").
The result of the command will be the value stored in "users.users.${user}". This value could be a set of options containing properties like the user's name, home directory, group, etc.