diff --git a/pkgs/servers/apcupsd/default.nix b/pkgs/servers/apcupsd/default.nix
index 58b3df1b436..b8a8cbbfa1c 100644
--- a/pkgs/servers/apcupsd/default.nix
+++ b/pkgs/servers/apcupsd/default.nix
@@ -39,7 +39,7 @@ stdenv.mkDerivation rec {
   postInstall = ''
     for file in "$out"/etc/apcupsd/*; do
         sed -i -e 's|^WALL=.*|WALL="${utillinux}/bin/wall"|g' \
-               -e 's|^HOSTNAME=.*|HOSTNAME="${nettools}/bin/hostname"|g' \
+               -e 's|^HOSTNAME=.*|HOSTNAME=`${nettools}/bin/hostname`|g' \
                "$file"
     done
   '';