diff --git a/internal/stage_multiple_matches_multiple_lines.go b/internal/stage_multiple_matches_multiple_lines.go
index bd75788..873ffbc 100644
--- a/internal/stage_multiple_matches_multiple_lines.go
+++ b/internal/stage_multiple_matches_multiple_lines.go
@@ -60,7 +60,7 @@ func testMultipleMatchesMultipleLines(stageHarness *test_case_harness.TestCaseHa
 		{
 			Pattern: fmt.Sprintf(`I saw \d+ (%s|%s)s?`, animal1, animal2),
 			InputLines: []string{
-				fmt.Sprintf("Yesterday I saw 3 %ss.", animal1),
+				fmt.Sprintf("Yesterday I saw 3 %s and I saw 45 %s.", animal1, animal2),
 				"Nothing interesting today.",
 				fmt.Sprintf("Last week I saw 12 %ss.", animal2),
 			},
diff --git a/internal/stages_test.go b/internal/stages_test.go
index 75054b6..b968cc9 100644
--- a/internal/stages_test.go
+++ b/internal/stages_test.go
@@ -134,6 +134,13 @@ func TestStages(t *testing.T) {
 			StdoutFixturePath:   "./test_helpers/fixtures/printing_matches/extra_empty_line",
 			NormalizeOutputFunc: normalizeTesterOutput,
 		},
+		"multiple_matches_pass": {
+			StageSlugs:          []string{"cj0", "ss2", "bo4"},
+			CodePath:            "./test_helpers/pass_all",
+			ExpectedExitCode:    0,
+			StdoutFixturePath:   "./test_helpers/fixtures/multiple_matches/success",
+			NormalizeOutputFunc: normalizeTesterOutput,
+		},
 	}
 
 	tester_utils_testing.TestTesterOutput(t, testerDefinition, testCases)
diff --git a/internal/test_helpers/fixtures/multiple_matches/success b/internal/test_helpers/fixtures/multiple_matches/success
new file mode 100644
index 0000000..b816508
--- /dev/null
+++ b/internal/test_helpers/fixtures/multiple_matches/success
@@ -0,0 +1,114 @@
+[tester::#CJ0] Running tests for Stage #CJ0 (cj0)
+[tester::#CJ0] $ echo -ne "only1digit" | ./your_grep.sh -o -E '\d'
+[your_program] 1
+[tester::#CJ0] ✓ Received exit code 0.
+[tester::#CJ0] ✓ Found line "1"
+[tester::#CJ0] ✓ Stdout contains 1 expected line in order
+[tester::#CJ0] $ echo -ne "cherry" | ./your_grep.sh -o -E '\d'
+[tester::#CJ0] ✓ Received exit code 1.
+[tester::#CJ0] ✓ No output found
+[tester::#CJ0] $ echo -ne "apple_suffix" | ./your_grep.sh -o -E '^apple'
+[your_program] apple
+[tester::#CJ0] ✓ Received exit code 0.
+[tester::#CJ0] ✓ Found line "apple"
+[tester::#CJ0] ✓ Stdout contains 1 expected line in order
+[tester::#CJ0] $ echo -ne "prefix_apple" | ./your_grep.sh -o -E '^apple'
+[tester::#CJ0] ✓ Received exit code 1.
+[tester::#CJ0] ✓ No output found
+[tester::#CJ0] $ echo -ne "cat" | ./your_grep.sh -o -E 'ca?t'
+[your_program] cat
+[tester::#CJ0] ✓ Received exit code 0.
+[tester::#CJ0] ✓ Found line "cat"
+[tester::#CJ0] ✓ Stdout contains 1 expected line in order
+[tester::#CJ0] $ echo -ne "I see 42 dogs" | ./your_grep.sh -o -E '^I see \d+ (cat|dog)s?$'
+[your_program] I see 42 dogs
+[tester::#CJ0] ✓ Received exit code 0.
+[tester::#CJ0] ✓ Found line "I see 42 dogs"
+[tester::#CJ0] ✓ Stdout contains 1 expected line in order
+[tester::#CJ0] Test passed.
+
+[tester::#SS2] Running tests for Stage #SS2 (ss2)
+[tester::#SS2] $ echo -ne "a1b2c3" | ./your_grep.sh -o -E '\d'
+[your_program] 1
+[your_program] 2
+[your_program] 3
+[tester::#SS2] ✓ Received exit code 0.
+[tester::#SS2] ✓ Found line "1"
+[tester::#SS2] ✓ Found line "2"
+[tester::#SS2] ✓ Found line "3"
+[tester::#SS2] ✓ Stdout contains 3 expected lines in order
+[tester::#SS2] $ echo -ne "pear_pineapple_watermelon" | ./your_grep.sh -o -E '(watermelon|pineapple|pear)'
+[your_program] pear
+[your_program] pineapple
+[your_program] watermelon
+[tester::#SS2] ✓ Received exit code 0.
+[tester::#SS2] ✓ Found line "pear"
+[tester::#SS2] ✓ Found line "pineapple"
+[tester::#SS2] ✓ Found line "watermelon"
+[tester::#SS2] ✓ Stdout contains 3 expected lines in order
+[tester::#SS2] $ echo -ne "cherry" | ./your_grep.sh -o -E '\d'
+[tester::#SS2] ✓ Received exit code 1.
+[tester::#SS2] ✓ No output found
+[tester::#SS2] $ echo -ne "xx, yy, zz" | ./your_grep.sh -o -E '\w\w'
+[your_program] xx
+[your_program] yy
+[your_program] zz
+[tester::#SS2] ✓ Received exit code 0.
+[tester::#SS2] ✓ Found line "xx"
+[tester::#SS2] ✓ Found line "yy"
+[tester::#SS2] ✓ Found line "zz"
+[tester::#SS2] ✓ Stdout contains 3 expected lines in order
+[tester::#SS2] $ echo -ne "##$$%" | ./your_grep.sh -o -E '\w'
+[tester::#SS2] ✓ Received exit code 1.
+[tester::#SS2] ✓ No output found
+[tester::#SS2] $ echo -ne "I see 3 tigers. Also, I see 4 pandas." | ./your_grep.sh -o -E 'I see \d+ (tiger|panda)s?'
+[your_program] I see 3 tigers
+[your_program] I see 4 pandas
+[tester::#SS2] ✓ Received exit code 0.
+[tester::#SS2] ✓ Found line "I see 3 tigers"
+[tester::#SS2] ✓ Found line "I see 4 pandas"
+[tester::#SS2] ✓ Stdout contains 2 expected lines in order
+[tester::#SS2] Test passed.
+
+[tester::#BO4] Running tests for Stage #BO4 (bo4)
+[tester::#BO4] $ echo -ne "a1b\nno digits here\n2c3d" | ./your_grep.sh -o -E '\d'
+[your_program] 1
+[your_program] 2
+[your_program] 3
+[tester::#BO4] ✓ Received exit code 0.
+[tester::#BO4] ✓ Found line "1"
+[tester::#BO4] ✓ Found line "2"
+[tester::#BO4] ✓ Found line "3"
+[tester::#BO4] ✓ Stdout contains 3 expected lines in order
+[tester::#BO4] $ echo -ne "I like plum\nnothing here\nwatermelon and plum are tasty" | ./your_grep.sh -o -E '(plum|watermelon)'
+[your_program] plum
+[your_program] watermelon
+[your_program] plum
+[tester::#BO4] ✓ Received exit code 0.
+[tester::#BO4] ✓ Found line "plum"
+[tester::#BO4] ✓ Found line "watermelon"
+[tester::#BO4] ✓ Found line "plum"
+[tester::#BO4] ✓ Stdout contains 3 expected lines in order
+[tester::#BO4] $ echo -ne "abc\ndef\nghi" | ./your_grep.sh -o -E 'XYZ123'
+[tester::#BO4] ✓ Received exit code 1.
+[tester::#BO4] ✓ No output found
+[tester::#BO4] $ echo -ne "dogdogdog\nelephant\ncat-cat-dog" | ./your_grep.sh -o -E 'cat'
+[your_program] cat
+[your_program] cat
+[tester::#BO4] ✓ Received exit code 0.
+[tester::#BO4] ✓ Found line "cat"
+[tester::#BO4] ✓ Found line "cat"
+[tester::#BO4] ✓ Stdout contains 2 expected lines in order
+[tester::#BO4] $ echo -ne "Yesterday I saw 3 panda and I saw 45 tiger.\nNothing interesting today.\nLast week I saw 12 tigers." | ./your_grep.sh -o -E 'I saw \d+ (panda|tiger)s?'
+[your_program] I saw 3 panda
+[your_program] I saw 45 tiger
+[your_program] I saw 12 tigers
+[tester::#BO4] ✓ Received exit code 0.
+[tester::#BO4] ✓ Found line "I saw 3 panda"
+[tester::#BO4] ✓ Found line "I saw 45 tiger"
+[tester::#BO4] ✓ Found line "I saw 12 tigers"
+[tester::#BO4] ✓ Stdout contains 3 expected lines in order
+[tester::#BO4] $ echo -ne "today is sunny\nno rains here\ntomorrow maybe rainy" | ./your_grep.sh -o -E 'cats and dogs'
+[tester::#BO4] ✓ Received exit code 1.
+[tester::#BO4] ✓ No output found
+[tester::#BO4] Test passed.
diff --git a/internal/test_helpers/pass_all/your_grep.sh b/internal/test_helpers/pass_all/your_grep.sh
index 3c569b6..c090026 100755
--- a/internal/test_helpers/pass_all/your_grep.sh
+++ b/internal/test_helpers/pass_all/your_grep.sh
@@ -1,13 +1,17 @@
-#!/bin/sh
-# GNU Grep:
-# From -E extended-regexp to -P perl-regexp
-if [ "$1" = "-E" ]; then
-    shift
-    set -- -P "$@"
-fi
+#!/bin/bash
+
+# Build new arguments, replacing -E with -P in place
+new_args=()
+for arg in "$@"; do
+    if [ "$arg" = "-E" ]; then
+        new_args+=("-P")
+    else
+        new_args+=("$arg")
+    fi
+done
 
 if [ "$(uname)" = "Darwin" ]; then
-    exec ggrep "$@"  # GNU grep from brew on macOS
+    exec ggrep "${new_args[@]}"  # GNU grep from brew on macOS
 else
-    exec "$(dirname "$0")/find_grep_linux.sh" "$@"
-fi
+    exec "$(dirname "$0")/find_grep_linux.sh" "${new_args[@]}"
+fi
\ No newline at end of file