diff --git a/dev/sg/internal/run/command.go b/dev/sg/internal/run/command.go
index 744f282a6b2..b198de7bccc 100644
--- a/dev/sg/internal/run/command.go
+++ b/dev/sg/internal/run/command.go
@@ -135,7 +135,7 @@ func startCmd(ctx context.Context, dir string, cmd Command, globalEnv map[string
 		stderrWriter = io.MultiWriter(logger, sc.stderrBuf)
 	}
 
-	wg, err := process.PipeOutput(ctx, sc.Cmd, stdoutWriter, stderrWriter)
+	wg, err := process.PipeOutputUnbuffered(ctx, sc.Cmd, stdoutWriter, stderrWriter)
 	if err != nil {
 		return nil, err
 	}
diff --git a/lib/process/pipe.go b/lib/process/pipe.go
index 8347ed521ec..2a5e1e1c857 100644
--- a/lib/process/pipe.go
+++ b/lib/process/pipe.go
@@ -17,6 +17,24 @@ import (
 //
 // See this issue for more details: https://github.com/golang/go/issues/21922
 func PipeOutput(ctx context.Context, c *exec.Cmd, stdoutWriter, stderrWriter io.Writer) (*sync.WaitGroup, error) {
+	return pipeOutputWithCopy(ctx, c, stdoutWriter, stderrWriter, func(w io.Writer, r io.Reader) {
+		scanner := bufio.NewScanner(r)
+		for scanner.Scan() {
+			fmt.Fprintln(w, scanner.Text())
+		}
+	})
+}
+
+func PipeOutputUnbuffered(ctx context.Context, c *exec.Cmd, stdoutWriter, stderrWriter io.Writer) (*sync.WaitGroup, error) {
+	return pipeOutputWithCopy(ctx, c, stdoutWriter, stderrWriter, func(w io.Writer, r io.Reader) {
+		_, err := io.Copy(w, r)
+		if err != nil {
+			panic(fmt.Sprintf("failed to pipe output: %s", err))
+		}
+	})
+}
+
+func pipeOutputWithCopy(ctx context.Context, c *exec.Cmd, stdoutWriter, stderrWriter io.Writer, fn copyFunc) (*sync.WaitGroup, error) {
 	stdoutPipe, err := c.StdoutPipe()
 	if err != nil {
 		return nil, err
@@ -42,10 +60,7 @@ func PipeOutput(ctx context.Context, c *exec.Cmd, stdoutWriter, stderrWriter io.
 	readIntoBuf := func(w io.Writer, r io.Reader) {
 		defer wg.Done()
 
-		scanner := bufio.NewScanner(r)
-		for scanner.Scan() {
-			fmt.Fprintln(w, scanner.Text())
-		}
+		fn(w, r)
 	}
 
 	wg.Add(2)
@@ -54,3 +69,5 @@ func PipeOutput(ctx context.Context, c *exec.Cmd, stdoutWriter, stderrWriter io.
 
 	return wg, nil
 }
+
+type copyFunc func(w io.Writer, r io.Reader)