diff --git a/pkgs/os-specific/linux/procps-ng/default.nix b/pkgs/os-specific/linux/procps-ng/default.nix
index 9f12ab695397..1d19d9151175 100644
--- a/pkgs/os-specific/linux/procps-ng/default.nix
+++ b/pkgs/os-specific/linux/procps-ng/default.nix
@@ -1,14 +1,19 @@
-{ lib, stdenv, fetchurl, fetchpatch, ncurses, pkg-config
+{ lib
+, stdenv
+, fetchurl
+, fetchpatch
+, ncurses
+, pkg-config
 
-# `ps` with systemd support is able to properly report different
-# attributes like unit name, so we want to have it on linux.
+  # `ps` with systemd support is able to properly report different
+  # attributes like unit name, so we want to have it on linux.
 , withSystemd ? stdenv.isLinux
-, systemd ? null
+, systemd
 
-# procps is mostly Linux-only. Most commands require a running Linux
-# system (or very similar like that found in Cygwin). The one
-# exception is ‘watch’ which is portable enough to run on pretty much
-# any UNIX-compatible system.
+  # procps is mostly Linux-only. Most commands require a running Linux
+  # system (or very similar like that found in Cygwin). The one
+  # exception is ‘watch’ which is portable enough to run on pretty much
+  # any UNIX-compatible system.
 , watchOnly ? !(stdenv.isLinux || stdenv.isCygwin)
 }:
 
@@ -35,28 +40,29 @@ stdenv.mkDerivation rec {
   nativeBuildInputs = [ pkg-config ];
 
   makeFlags = [ "usrbin_execdir=$(out)/bin" ]
-    ++ lib.optionals watchOnly [ "watch" "PKG_LDFLAGS="];
+    ++ lib.optionals watchOnly [ "watch" "PKG_LDFLAGS=" ];
 
   enableParallelBuilding = true;
 
   # Too red
   configureFlags = [ "--disable-modern-top" ]
     ++ lib.optional withSystemd "--with-systemd"
-    ++ lib.optionals (stdenv.hostPlatform != stdenv.buildPlatform)
-    [ "ac_cv_func_malloc_0_nonnull=yes"
-      "ac_cv_func_realloc_0_nonnull=yes" ];
+    ++ lib.optionals (stdenv.hostPlatform != stdenv.buildPlatform) [
+    "ac_cv_func_malloc_0_nonnull=yes"
+    "ac_cv_func_realloc_0_nonnull=yes"
+  ];
 
-  installPhase = if watchOnly then ''
+  installPhase = lib.optionalString watchOnly ''
     install -m 0755 -D watch $out/bin/watch
     install -m 0644 -D watch.1 $out/share/man/man1/watch.1
-  '' else null;
+  '';
 
-  meta = {
+  meta = with lib; {
     homepage = "https://gitlab.com/procps-ng/procps";
     description = "Utilities that give information about processes using the /proc filesystem";
     priority = 11; # less than coreutils, which also provides "kill" and "uptime"
-    license = lib.licenses.gpl2;
-    platforms = lib.platforms.unix;
-    maintainers = [ lib.maintainers.typetetris ];
+    license = licenses.gpl2;
+    platforms = platforms.unix;
+    maintainers = [ maintainers.typetetris ];
   };
 }