first commit

cli/internal/update/replace.go

@@ -0,0 +1,11 @@
+//go:build !windows
+
+package update
+
+import "os"
+
+// atomicReplace replaces oldPath with newPath using os.Rename.
+// On Unix systems, this is atomic if both paths are on the same filesystem.
+func atomicReplace(oldPath, newPath string) error {
+	return os.Rename(newPath, oldPath)
+}