nix-instantiate instantiate store derivations from Nix expressions nix-instantiate --arg name value --attr -A attrPath --add-root path --indirect --parse-only --eval-only files The command nix-instantiate generates store derivations from (high-level) Nix expressions. It loads and evaluates the Nix expressions in each of files. Each top-level expression should evaluate to a derivation, a list of derivations, or a set of derivations. The paths of the resulting store derivations are printed on standard output. If files is the character -, then a Nix expression will be read from standard input. Most users and developers don’t need to use this command (nix-env and nix-build perform store derivation instantiation from Nix expressions automatically). It is most commonly used for implementing new deployment policies. See also for a list of common options. --add-root path --indirect See the corresponding options in nix-store. --parse-only Just parse the input files, and print their abstract syntax trees on standard output in ATerm format. --eval-only Just parse and evaluate the input files, and print the resulting values on standard output. No instantiation of store derivations takes place. $ nix-instantiate test.nix (instantiate) /nix/store/cigxbmvy6dzix98dxxh9b6shg7ar5bvs-perl-BerkeleyDB-0.26.drv $ nix-store -r $(nix-instantiate test.nix) (build) ... /nix/store/qhqk4n8ci095g3sdp93x7rgwyh9rdvgk-perl-BerkeleyDB-0.26 (output path) $ ls -l /nix/store/qhqk4n8ci095g3sdp93x7rgwyh9rdvgk-perl-BerkeleyDB-0.26 dr-xr-xr-x 2 eelco users 4096 1970-01-01 01:00 lib ...