diff --git a/zip/cmd/main.go b/zip/cmd/main.go
index a2ccc20..5231fae 100644
--- a/zip/cmd/main.go
+++ b/zip/cmd/main.go
@@ -173,6 +173,7 @@
 	cpuProfile := flags.String("cpuprofile", "", "write cpu profile to file")
 	traceFile := flags.String("trace", "", "write trace to file")
 	sha256Checksum := flags.Bool("sha256", false, "add a zip header to each file containing its SHA256 digest")
+	doNotWrite := flags.Bool("n", false, "Nothing is written to disk -- all other work happens")
 
 	flags.Var(&rootPrefix{}, "P", "path prefix within the zip at which to place files")
 	flags.Var(&listFiles{}, "l", "file containing list of files to zip")
@@ -236,6 +237,7 @@
 		StoreSymlinks:            *symlinks,
 		IgnoreMissingFiles:       *ignoreMissingFiles,
 		Sha256Checksum:           *sha256Checksum,
+		DoNotWrite:               *doNotWrite,
 	})
 	if err != nil {
 		fmt.Fprintln(os.Stderr, "error:", err.Error())
diff --git a/zip/zip.go b/zip/zip.go
index 5e1a104..30a2ee7 100644
--- a/zip/zip.go
+++ b/zip/zip.go
@@ -282,6 +282,7 @@
 	StoreSymlinks            bool
 	IgnoreMissingFiles       bool
 	Sha256Checksum           bool
+	DoNotWrite               bool
 
 	Stderr     io.Writer
 	Filesystem pathtools.FileSystem
@@ -400,7 +401,9 @@
 
 	var zipErr error
 
-	if !args.WriteIfChanged {
+	if args.DoNotWrite {
+		out = io.Discard
+	} else if !args.WriteIfChanged {
 		f, err := os.Create(args.OutputFilePath)
 		if err != nil {
 			return err
@@ -421,7 +424,7 @@
 		return zipErr
 	}
 
-	if args.WriteIfChanged {
+	if args.WriteIfChanged && !args.DoNotWrite {
 		err := pathtools.WriteFileIfChanged(args.OutputFilePath, buf.Bytes(), 0666)
 		if err != nil {
 			return err