need this script to auto-edit the xv6 Makefile for testing

tester/xv6-edit-makefile.sh

@@ -0,0 +1,16 @@
+#! /bin/bash
+
+infile=$1
+testnames=$2
+
+gawk -vtestnames=$testnames '
+($1 == "_mkdir\\") {
+  n = split(testnames, x, ",");
+  for (i = 1; i <= n; i++) {
+    printf("\t_%s\\\n", x[i]);
+  }
+} 
+
+{
+  print $0;
+}' $infile