diff --git a/options/auto-upgrade.nix b/options/auto-upgrade.nix
index a57b468..f365c9e 100644
--- a/options/auto-upgrade.nix
+++ b/options/auto-upgrade.nix
@@ -44,9 +44,6 @@ in
             let
                 nixos-rebuild = "${config.system.build.nixos-rebuild}/bin/nixos-rebuild";
                 nix-store = "${pkgs.nix}/bin/nix-store";
-                date = "${pkgs.coreutils}/bin/date";
-                readlink = "${pkgs.coreutils}/bin/readlink";
-                grep = "${pkgs.gnugrep}/bin/grep";
                 diff = "${pkgs.diffutils}/bin/diff";
                 git = "${pkgs.git}/bin/git";
                 ssh = "${pkgs.openssh}/bin/ssh";
@@ -64,7 +61,7 @@ in
                     done <<< "$1"
                 }
 
-                start_time="$(${date})"
+                start_time="$(date)"
                 reboot_allowed="no"
                 activate_configuration="yes"
                 do_reboot="no"
@@ -135,8 +132,8 @@ in
                     <(printf "New generation\n--------------\n%s" "$built_packages") \
                     | tee -a "$output_file" || true
 
-                booted_version="$(${readlink} /run/booted-system/{initrd,kernel,kernel-modules})"
-                built_version="$(${readlink} /nix/var/nix/profiles/system/{initrd,kernel,kernel-modules})"
+                booted_version="$(readlink /run/booted-system/{initrd,kernel,kernel-modules})"
+                built_version="$(readlink /nix/var/nix/profiles/system/{initrd,kernel,kernel-modules})"
 
                 echo "→ Checking if a reboot is needed." | tee -a "$output_file"
                 if [ "$booted_version" != "$built_version" ] ; then
@@ -181,7 +178,7 @@ in
                 upgrade_output="$(cat "$output_file")"
                 rm -f "$output_file"
 
-                possible_warnings="$(${grep} -e "^\(warning\|trace\):" <<<"$upgrade_output" || true)"
+                possible_warnings="$(grep -e "^\(warning\|trace\):" <<<"$upgrade_output" || true)"
                 if [ "$possible_warnings" != "" ] ; then
                     send_email=yes
                     email_subject_additions="$email_subject_additions with warnings"