Michael Opdenacker contributed a readahead applet.

miscutils/readahead.c

@@ -0,0 +1,36 @@
+/* vi: set sw=4 ts=4: */
+/*
+ * readahead implementation for busybox
+ *
+ * Preloads the given files in RAM, to reduce access time.
+ * Does this by calling the readahead(2) system call.
+ *
+ * Copyright (C) 2006  Michael Opdenacker <michael@free-electrons.com>
+ *
+ * Licensed under GPLv2 or later, see file License in this tarball for details.
+ */
+
+#include "busybox.h"
+
+int readahead_main(int argc, char **argv)
+{
+	FILE *f;
+	struct stat stat_buf;
+	int retval = EXIT_SUCCESS;
+
+	if (argc == 1) bb_show_usage();
+
+	while (*++argv) {
+		if ((f = bb_wfopen(*argv, "r")) != NULL) {
+			int r, fd=fileno(f);
+			
+			xstat(*argv, &stat_buf);
+			r = readahead(fd, 0, fdlength(fd));
+			fclose(f);
+			if (r >= 0) continue;
+		}
+		retval = EXIT_FAILURE;
+	}
+
+	return retval;
+}