gistfile1.txt

#!/bin/sh

set -eu
set -o pipefail

buildHost=root@yourremotebuilder

tmpDir=$(mktemp -t -d nixos-rebuild.XXXXXX)
SSHOPTS="${NIX_SSHOPTS:-} -o ControlMaster=auto -o ControlPath=$tmpDir/ssh-%n -o ControlPersist=60"

cleanup() {
    for ctrl in "$tmpDir"/ssh-*; do
        ssh -o ControlPath="$ctrl" -O exit dummyhost 2>/dev/null || true
    done
    rm -rf "$tmpDir"
}
trap cleanup EXIT

set -eux

drv=$(nix-instantiate ./your-thing-to-build.nix -A foobar)
NIX_SSHOPTS=$SSHOPTS nix-copy-closure --to "$buildHost" "$drv"
out=$(ssh $SSHOPTS "$buildHost" "NIX_REMOTE=daemon nix-store -r '$drv' -j 5")

nix-copy-closure --from "$buildHost" "$out"