compressLogs = pkgs.writeScript "compress-logs" ''
           #! ${pkgs.stdenv.shell} -e
           find /nix/var/log/nix/drvs \
                -type f -a ! -newermt 'last month' \
                -name '*.drv' -exec bzip2 -v {} +
         '';

          "15 5 * * * root  ${compressLogs} &> ${baseDir}/data/compress.log"