diff --git a/CHANGELOG.md b/CHANGELOG.md
index 2a7b895..03ade9a 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -17,6 +17,10 @@ See [Semver](http://semver.org/).
 - 🐞 Backwards-compatible bug fixes
 - 📦 Minor packaging changes
 
+## v5.2.1
+
+- 🐞 `.pass` and `.fail` regex now support multiple line outputs per task.
+
 ## v5.2.0
 
 - 🐞 [BatchProcessOptions](https://batch-cluster.js.org/classes/batchclusteroptions.html)`.pass`
diff --git a/src/BatchCluster.spec.ts b/src/BatchCluster.spec.ts
index b7079bd..128d4fc 100644
--- a/src/BatchCluster.spec.ts
+++ b/src/BatchCluster.spec.ts
@@ -273,6 +273,28 @@ describe("BatchCluster", function() {
               )
             })
 
+            it("accepts single and multi-line responses", async () => {
+              setFailrate(0)
+              const expected: string[] = []
+              const results = await Promise.all(
+                times(15, idx => {
+                  // Make a distribution of single, double, and triple line outputs:
+                  const worlds = times(idx % 3, ea => "world " + ea)
+                  expected.push(
+                    [idx + " HELLO", ...worlds]
+                      .join("\n")
+                      .toUpperCase()
+                  )
+                  const cmd = ["upcase " + idx + " hello", ...worlds].join(
+                    "<br>"
+                  )
+                  return bc.enqueueTask(new Task(cmd, parser))
+                })
+              )
+              expect(results).to.eql(expected)
+              return
+            })
+
             it("rejects a command that results in FAIL", async function() {
               const task = new Task("invalid command", parser)
               let error: Error | undefined
diff --git a/src/BatchClusterOptions.ts b/src/BatchClusterOptions.ts
index 51605b8..7c45420 100644
--- a/src/BatchClusterOptions.ts
+++ b/src/BatchClusterOptions.ts
@@ -1,7 +1,7 @@
-import { BatchProcessOptions } from "./BatchProcessOptions"
 import { ChildProcessFactory } from "./BatchCluster"
+import { BatchProcessOptions } from "./BatchProcessOptions"
 import { InternalBatchProcessOptions } from "./InternalBatchProcessOptions"
-import { toS, blank } from "./String"
+import { blank, toS } from "./String"
 
 /**
  * These parameter values have somewhat sensible defaults, but can be
@@ -113,7 +113,7 @@ export type AllOpts = BatchClusterOptions &
 function toRe(s: string | RegExp) {
   return s instanceof RegExp
     ? s
-    : new RegExp("^(?:(.*)(?:\\r?\\n))?" + s + "(?:\\r?\\n)?$")
+    : new RegExp("^(?:([\\s\\S]*?)(?:\\r?\\n))?" + s + "(?:\\r?\\n)?$")
 }
 
 export function verifyOptions(
diff --git a/src/test.ts b/src/test.ts
index 3a2546d..9a419de 100644
--- a/src/test.ts
+++ b/src/test.ts
@@ -35,7 +35,7 @@ const rng =
       Math.random
 
 async function onLine(line: string): Promise<void> {
-  // write(`# ${_p.pid} onLine(${line.trim()})`)
+  // write(`# ${_p.pid} onLine(${line.trim()}) (newline = ${_p.env.newline})`)
   const r = rng()
   if (r < failrate) {
     if (_p.env.unluckyfail === "1") {
@@ -58,6 +58,9 @@ async function onLine(line: string): Promise<void> {
   const tokens = line.split(/\s+/)
   const firstToken = tokens.shift()
 
+  // support multi-line outputs:
+  const postToken = tokens.join(" ").split("<br>").join(newline)
+
   try {
     switch (firstToken) {
       case "flaky":
@@ -81,12 +84,12 @@ async function onLine(line: string): Promise<void> {
         break
 
       case "upcase":
-        write(tokens.join(" ").toUpperCase())
+        write(postToken.toUpperCase())
         write("PASS")
         break
 
       case "downcase":
-        write(tokens.join(" ").toLowerCase())
+        write(postToken.toLowerCase())
         write("PASS")
         break
 
@@ -115,7 +118,7 @@ async function onLine(line: string): Promise<void> {
         // debouncing:
         write("PASS")
         await delay(1)
-        console.error("Error: " + tokens.join(" "))
+        console.error("Error: " + postToken)
         break
 
       default: