[root@nixos:/etc/nixos]# nixos-rebuild switch --show-trace
building Nix...
building the system configuration...
these derivations will be built:
  /nix/store/jw4cjhgcjsv7hp91vmyshl51pvqd35d5-postgresql-and-plugins-10.1.drv
  /nix/store/fga357a4z2b5h4flcfkxjzijrn5w6bwi-system-path.drv
  /nix/store/8698sa0sg6x86l9zkvmdxnx917hh3h9r-dbus-1.drv
  /nix/store/1hyxzsizif0zc0xk0jh8vm4mydaq4j3m-unit-dbus.service.drv
  /nix/store/5bpdxnf5l5l3r03fmixpzr8yngbd7acy-usermod.pam.drv
  /nix/store/8nwjjwjgjbs6bg637qnbxv4lq7p5cykx-systemd-user.pam.drv
  /nix/store/8p06x4zplddsvcq32bbfjwn282s1i58j-xscreensaver.pam.drv
  /nix/store/8zpiqijgyhnxbkb42hhay44vnvx1232m-runuser-l.pam.drv
  /nix/store/922s0vjzdqwkp0cmp2sv2p1bjjrsb4j0-vlock.pam.drv
  /nix/store/agx2pvkrcyk6nxswqw42mqn2mz7bxg3i-slim.pam.drv
  /nix/store/b8p8sw5mw8562frz2ljjydjfcafzg4im-userdel.pam.drv
  /nix/store/blhh09hc0wsxds59bkh99yj415ayarbc-sshd.pam.drv
  /nix/store/clgcyjbamkwpvyfba7ic9xx79cnn0g3y-screen.pam.drv
  /nix/store/dpv5c5xscz0hrbnn59gzjs8a3b3hvfqg-unit-postgresql.service.drv
  /nix/store/k4rc7mnsvq90bflpa37qjng9bcrhl3y1-unit-nixos-upgrade.service.drv
  /nix/store/mvbpflp5rx9k4479058q04dkdpsvmrzm-unit-polkit.service.drv
  /nix/store/w066vb892ddqz6907calygz7cbiih2yg-unit-systemd-fsck-.service.drv
  /nix/store/cyajlx1dp5asizql7i33x7y7m0q9wgxh-system-units.drv
  /nix/store/gmgw4ynig0p2kl8f427wj2gg7d3jq5w8-sddm.pam.drv
  /nix/store/hbx751g7l6nwdzn6s1s02yyac051zy88-sddm-greeter.pam.drv
  /nix/store/hwjsx04g7y5dja32hmq6c2d2ma417jw6-user-units.drv
  /nix/store/iaqf3himr0g69xdfivig1p8x0h9q5hw9-xlock.pam.drv
  /nix/store/mbyrb2aprijiggwigjwqhpln3rbp6sp3-useradd.pam.drv
  /nix/store/pd0qvb20rgbnp6rwlw0hki3ds8adn3sc-sudo.pam.drv
  /nix/store/rwyp2jpms0lg58blw1pp6rn6kn062vjx-su.pam.drv
  /nix/store/l98pcqlv8a725d873l4pl1cjylb5szzx-etc.drv
  /nix/store/7cs7398zd6gpyk8p3qg59vpsmzfc6pa6-nixos-system-nixos-18.03.132083.06c576b0525.drv
building '/nix/store/8zpiqijgyhnxbkb42hhay44vnvx1232m-runuser-l.pam.drv'...
building '/nix/store/jw4cjhgcjsv7hp91vmyshl51pvqd35d5-postgresql-and-plugins-10.1.drv'...
created 324 symlinks in user environment
rm: cannot remove '/nix/store/9sj6qp97pi3gfdawg92xs94w4lpqmp4k-postgresql-and-plugins-10.1/bin/pg_config': Permission denied
rm: cannot remove '/nix/store/9sj6qp97pi3gfdawg92xs94w4lpqmp4k-postgresql-and-plugins-10.1/bin/postgres': Permission denied
rm: cannot remove '/nix/store/9sj6qp97pi3gfdawg92xs94w4lpqmp4k-postgresql-and-plugins-10.1/bin/pg_ctl': Permission denied
builder for '/nix/store/jw4cjhgcjsv7hp91vmyshl51pvqd35d5-postgresql-and-plugins-10.1.drv' failed with exit code 1
building '/nix/store/clgcyjbamkwpvyfba7ic9xx79cnn0g3y-screen.pam.drv'...
cannot build derivation '/nix/store/fga357a4z2b5h4flcfkxjzijrn5w6bwi-system-path.drv': 1 dependencies couldn't be built
cannot build derivation '/nix/store/dpv5c5xscz0hrbnn59gzjs8a3b3hvfqg-unit-postgresql.service.drv': 1 dependencies couldn't be built
cannot build derivation '/nix/store/7cs7398zd6gpyk8p3qg59vpsmzfc6pa6-nixos-system-nixos-18.03.132083.06c576b0525.drv': 1 dependencies couldn't be built
error: build of '/nix/store/7cs7398zd6gpyk8p3qg59vpsmzfc6pa6-nixos-system-nixos-18.03.132083.06c576b0525.drv' failed