diff --git a/Library/Homebrew/commands.rb b/Library/Homebrew/commands.rb
index cf91bafa60..02fc3d5e05 100644
--- a/Library/Homebrew/commands.rb
+++ b/Library/Homebrew/commands.rb
@@ -148,8 +148,7 @@ module Commands
     cmds = internal_commands + internal_developer_commands + internal_commands_aliases
 
     file = HOMEBREW_REPOSITORY/"completions/internal_commands_list.txt"
-    file.delete if file.exist?
-    file.write(cmds.sort.join("\n") + "\n")
+    file.atomic_write(cmds.sort.join("\n") + "\n")
   end
 
   def rebuild_commands_completion_list
@@ -157,7 +156,6 @@ module Commands
     HOMEBREW_CACHE.mkpath
 
     file = HOMEBREW_CACHE/"all_commands_list.txt"
-    file.delete if file.exist?
-    file.write(commands(aliases: true).sort.join("\n") + "\n")
+    file.atomic_write(commands(aliases: true).sort.join("\n") + "\n")
   end
 end