fix commands

Author: BNH440

modules/printhost/cups.nix

@@ -24,19 +24,16 @@ let
   # of the backend, which inherits CUPS's restricted PATH.
   enforcerPc = pkgs.writeShellScript "enforcer-pc" ''
     set -euo pipefail
-    (${pkgs.coreutils}/bin/head -n20; ${pkgs.coreutils}/bin/tail -n20) < "$1" \
-      | ${pkgs.gawk}/bin/awk '/^%%Pages: [0-9]+$/ {print $2}'
+    ${pkgs.gawk}/bin/awk '/^%%Pages: [0-9]+$/ {print $2; exit}' "$1"
   '';
 
   # enforcer-size: reads %%DocumentMedia:/%%PageMedia: from PostScript spool file.
   enforcerSize = pkgs.writeShellScript "enforcer-size" ''
     set -euo pipefail
-    (${pkgs.coreutils}/bin/head -n20; ${pkgs.coreutils}/bin/tail -n20) < "$1" \
-      | ${pkgs.gawk}/bin/awk '
-          /^%%PageMedia:/    {print $2}
-          /^%%DocumentMedia:/ {print $2}
-        ' \
-      | ${pkgs.coreutils}/bin/head -n1
+    ${pkgs.gawk}/bin/awk '
+        /^%%PageMedia:/    {print $2; exit}
+        /^%%DocumentMedia:/ {print $2; exit}
+      ' "$1"
   '';
 
   # enforcer.py with @enforcer_pc@ and @enforcer_size@ paths substituted