further shell updates

kernel/bin/test

@@ -215,5 +215,20 @@ async function evalTest(ctx, args) {
 }
 
 async function run(ctx, argv) {
-  ctx.exitCode = (await evalTest(ctx, argv.slice(1))) ? 0 : 1
+  const prog0 = argv[0] != null ? String(argv[0]) : ''
+  let testArgs = argv.slice(1)
+  if (prog0 === '[' || prog0.endsWith('/[')) {
+    if (!testArgs.length) {
+      ctx.console.error('[: missing ]')
+      ctx.exitCode = 2
+      return
+    }
+    if (testArgs[testArgs.length - 1] !== ']') {
+      ctx.console.error('[: expected ]')
+      ctx.exitCode = 2
+      return
+    }
+    testArgs = testArgs.slice(0, -1)
+  }
+  ctx.exitCode = (await evalTest(ctx, testArgs)) ? 0 : 1
 }