nix/os/containers/backup: add common safety options to shell script

nix/os/containers/backup.nix

@@ -126,6 +126,8 @@ in args // {
       '';
       script = ''
         #! ${pkgs.bash}/bin/bash
+        set -Eeuxo pipefail
+
         export RUST_BACKTRACE=1
         export TIMESTAMP=$(date +"%Y%m%d.%H%M%S")
 
@@ -133,9 +135,7 @@ in args // {
         for d in `ls -1 ${bkpSource}`; do
           echo Determining backup source size ${bkpSource}/$d...
           du -hs ${bkpSource}/$d
-          set -x
           rdup -x /dev/null ${bkpSource}/$d | rdedup -v -ttt --dir=${bkpDestination}/rdedup store $d-''${TIMESTAMP}
-          set +x
         done
         sync
         echo Finished rdup/rdedup backup...