Nix install without root access

install-nix-no-root.sh

function install_nix() {
  set -x
  local -r bindir="${HOME}/bin"
  local -r proot_url="https://github.com/proot-me/proot/releases/download/v5.3.0/proot-v5.3.0-x86_64-static"
  local -r nixdir="${HOME}/mnt/nix"
  local -r nixver="2.5.1"
  local -r arch="x86_64"
  local -r os="linux"
  local -r nix_url="https://releases.nixos.org/nix/nix-${nixver}/nix-${nixver}-${arch}-${os}.tar.xz"
  local -r nix_cli_dir=nix-${nixver}-${arch}-${os}

  mkdir -p "${bindir}"
  test \! -f "${bindir}/proot" && curl -L "${proot_url}" > "${bindir}/proot"
  chmod u+x "${bindir}/proot"

  mkdir -p "${nixdir}"
  pushd "${nixdir}"
  test \! -f nix.tar.xz && curl -L "${nix_url}" > nix.tar.xz
  test \! -d $nix_cli_dir && tar -xJf "nix.tar.xz"
  local -r nixbin="$(dirname "$(find "${nixdir}/${nix_cli_dir}" -name "nix-shell" | head -1)")"
  local -r nix_profile="$(dirname $nixbin)/etc/profile.d/nix.sh"
  {
    echo "#!/usr/bin/env bash"
    echo
    echo export PATH="${bindir}:${nixbin}:${PATH}"
    echo source "${nix_profile}"
    echo export PROOT_NO_SECCOMP=1
    echo export NIX_PATH=\${NIX_PATH:+\$NIX_PATH:}\$HOME/.nix-defexpr/channels
    echo
    echo "${bindir}/proot -b \"${nixdir}/nix-${nixver}-${arch}-${os}/:/nix\" \$@"
  } > "${bindir}/nixrun"
  chmod u+x "${bindir}/nixrun"
}

set -eu
set -o pipefail

install_nix

mkdir -p ${HOME}/.config/nix
echo "sandbox = false" > ${HOME}/.config/nix/nix.conf
nixrun /nix/install --no-daemon --no-channel-add
grep -qF 'nixrun' ~/.bashrc || echo 'test \! -e $HOME/.nix-profile && nixrun bash -l' >> ${HOME}/.bashrc
cat >> $HOME/.nix-channels << EOF
https://github.com/rycee/home-manager/archive/release-21.11.tar.gz home-manager
https://github.com/NixOS/nixpkgs/archive/release-21.11.tar.gz nixpkgs
EOF
nixrun nix-channel --update
nixrun nix-shell '<home-manager>' -A install