add ,xz parallel compressor

pkgs/tb-scripts/default.nix

@@ -12,23 +12,33 @@ pkgs.symlinkJoin {
       runtimeInputs = [ pkgs.jq ];
       text = builtins.readFile ./jq_reformat.sh;
     })
+
     (pkgs.writers.writePython3Bin ",rename_lower" {
       libraries = [ ];
     } (builtins.readFile ./rename_lower.py))
+
     (pkgs.writeShellApplication {
       name = ",zipdir";
       runtimeInputs = [ pkgs.zip ];
       text = builtins.readFile ./zipdir;
     })
+
     (pkgs.writeShellApplication {
       name = ",split-1G";
       runtimeInputs = [ pkgs.coreutils ];
       text = builtins.readFile ./split-1G;
     })
+
     (pkgs.writeShellApplication {
       name = ",pushover-send";
       runtimeInputs = [ pkgs.curl ];
       text = builtins.readFile ./pushover-send;
     })
+
+    (pkgs.writeShellApplication {
+      name = ",xz";
+      runtimeInputs = [ pkgs.xz ];
+      text = builtins.readFile ./xz;
+    })
   ];
 }

pkgs/tb-scripts/xz

@@ -0,0 +1,13 @@
+#!/bin/sh -x
+
+PROCS=$(grep -c ^processor /proc/cpuinfo)
+
+if [ $# -eq 0 ]; then
+    (for f in *; do
+         echo "$f";
+     done) | xargs -P"$PROCS" -d'\n' -n1 xz -9ve
+else
+    (for f in "$@"; do
+         echo "$f";
+     done) | xargs -P"$PROCS" -d'\n' -n1 xz -9ve
+fi