diff --git a/app/controllers/admin/backups_controller.rb b/app/controllers/admin/backups_controller.rb
index 3eb3f62772..c49b6aeeb8 100644
--- a/app/controllers/admin/backups_controller.rb
+++ b/app/controllers/admin/backups_controller.rb
@@ -215,7 +215,7 @@ class Admin::BackupsController < Admin::AdminController
   private
 
   def has_enough_space_on_disk?(size)
-    `df -Pk #{Rails.root}/public/backups | awk 'NR==2 {printf "%.0f", $4 * 1024;}'`.to_i > size
+    DiskSpace.free("#{Rails.root}/public/backups") > size
   end
 
   def ensure_backups_enabled
diff --git a/lib/cooked_post_processor.rb b/lib/cooked_post_processor.rb
index 9846c9e0bb..3d85718fb5 100644
--- a/lib/cooked_post_processor.rb
+++ b/lib/cooked_post_processor.rb
@@ -685,7 +685,7 @@ class CookedPostProcessor
   end
 
   def available_disk_space
-    100 - `df -P #{Rails.root}/public/uploads | tail -1 | tr -s ' ' | cut -d ' ' -f 5`.to_i
+    100 - DiskSpace.percent_free("#{Rails.root}/public/uploads")
   end
 
   def dirty?
diff --git a/lib/disk_space.rb b/lib/disk_space.rb
index 96121b0cc7..f3cfd25612 100644
--- a/lib/disk_space.rb
+++ b/lib/disk_space.rb
@@ -12,11 +12,19 @@ class DiskSpace
   end
 
   def self.free(path)
-    `df -Pk #{path} | awk 'NR==2 {print $4;}'`.to_i * 1024
+    output = Discourse::Utils.execute_command('df', '-Pk', path)
+    size_line = output.split("\n")[1]
+    size_line.split(/\s+/)[3].to_i * 1024
+  end
+
+  def self.percent_free(path)
+    output = Discourse::Utils.execute_command('df', '-P', path)
+    size_line = output.split("\n")[1]
+    size_line.split(/\s+/)[4].to_i
   end
 
   def self.used(path)
-    `du -s #{path}`.to_i * 1024
+    Discourse::Utils.execute_command("du", "-s", path).to_i * 1024
   end
 
   def self.uploads_path