diff --git a/main_test.go b/main_test.go
index c54f8cc..8e33e4c 100644
--- a/main_test.go
+++ b/main_test.go
@@ -9,8 +9,8 @@ import (
 	"os"
 	"os/exec"
 	"path/filepath"
-	"regexp"
 	"runtime"
+	"strings"
 	"testing"
 
 	"github.com/rogpeppe/go-internal/gotooltest"
@@ -47,8 +47,8 @@ func TestScripts(t *testing.T) {
 			return nil
 		},
 		Cmds: map[string]func(ts *testscript.TestScript, neg bool, args []string){
-			"bingrep": bingrep,
-			"bincmp":  bincmp,
+			"binsubstr": binsubstr,
+			"bincmp":    bincmp,
 		},
 		UpdateScripts: *update,
 	}
@@ -58,19 +58,17 @@ func TestScripts(t *testing.T) {
 	testscript.Run(t, p)
 }
 
-func bingrep(ts *testscript.TestScript, neg bool, args []string) {
+func binsubstr(ts *testscript.TestScript, neg bool, args []string) {
 	if len(args) < 2 {
-		ts.Fatalf("usage: bingrep file pattern...")
+		ts.Fatalf("usage: binsubstr file substr...")
 	}
 	data := ts.ReadFile(args[0])
-	for _, pattern := range args[1:] {
-		rx, err := regexp.Compile(pattern)
-		ts.Check(err)
-		match := rx.MatchString(data)
+	for _, substr := range args[1:] {
+		match := strings.Contains(data, substr)
 		if match && neg {
-			ts.Fatalf("unexpected match for %q in %s", pattern, args[0])
+			ts.Fatalf("unexpected match for %q in %s", substr, args[0])
 		} else if !match && !neg {
-			ts.Fatalf("expected match for %q in %s", pattern, args[0])
+			ts.Fatalf("expected match for %q in %s", substr, args[0])
 		}
 	}
 }
diff --git a/testdata/scripts/basic.txt b/testdata/scripts/basic.txt
index d9fd2be..33aea0a 100644
--- a/testdata/scripts/basic.txt
+++ b/testdata/scripts/basic.txt
@@ -10,8 +10,8 @@ cmp stderr main.stderr
 
 # The default build includes full non-trimmed paths, as well as our names.
 # Only check $WORK on non-windows, because it's difficult to do it there.
-bingrep main$exe 'globalVar' 'globalFunc'
-[!windows] bingrep main$exe ${WORK@R}
+binsubstr main$exe 'globalVar' 'globalFunc'
+[!windows] binsubstr main$exe ${WORK@R}
 
 # Check that we fail if the user forgot -trimpath.
 ! exec go build -a -toolexec=garble main.go
@@ -26,7 +26,7 @@ cmp stderr main.stderr
 [!windows] [exec:readelf] ! stdout 'debug_info'
 [!windows] [exec:readelf] ! stdout '\.symtab'
 
-! bingrep main$exe ${WORK@R} 'globalVar' 'globalFunc'
+! binsubstr main$exe ${WORK@R} 'globalVar' 'globalFunc'
 
 [short] stop # checking that the build is reproducible is slow
 
@@ -35,7 +35,7 @@ cmp stderr main.stderr
 cp main$exe main_old$exe
 rm main$exe
 garble build main.go
-! bingrep main$exe 'globalVar'
+! binsubstr main$exe 'globalVar'
 bincmp main$exe main_old$exe
 
 -- main.go --
diff --git a/testdata/scripts/implement.txt b/testdata/scripts/implement.txt
index 7a605a8..a1eaedf 100644
--- a/testdata/scripts/implement.txt
+++ b/testdata/scripts/implement.txt
@@ -2,7 +2,7 @@ garble build main.go
 exec ./main
 cmp stdout main.stdout
 
-! bingrep main$exe 'unexportedMethod'
+! binsubstr main$exe 'unexportedMethod'
 
 -- main.go --
 package main
diff --git a/testdata/scripts/imports.txt b/testdata/scripts/imports.txt
index fbfb0db..5f9e395 100644
--- a/testdata/scripts/imports.txt
+++ b/testdata/scripts/imports.txt
@@ -2,7 +2,7 @@ garble build
 exec ./main
 cmp stdout main.stdout
 
-! bingrep main$exe 'ImportedVar' 'ImportedConst' 'ImportedFunc' 'ImportedType'
+! binsubstr main$exe 'ImportedVar' 'ImportedConst' 'ImportedFunc' 'ImportedType'
 
 [short] stop # checking that the build is reproducible is slow
 
diff --git a/testdata/scripts/modinfo.txt b/testdata/scripts/modinfo.txt
index eab1305..84071fd 100644
--- a/testdata/scripts/modinfo.txt
+++ b/testdata/scripts/modinfo.txt
@@ -1,12 +1,12 @@
 exec go build
 exec ./main
 cmp stdout main.stdout-orig
-bingrep main$exe '\(devel\)'
+binsubstr main$exe '(devel)'
 
 garble build
 exec ./main
 cmp stdout main.stdout
-! bingrep main$exe '\(devel\)'
+! binsubstr main$exe '(devel)'
 
 -- go.mod --
 module foo.com/main
diff --git a/testdata/scripts/test.txt b/testdata/scripts/test.txt
index 398cd89..e47f459 100644
--- a/testdata/scripts/test.txt
+++ b/testdata/scripts/test.txt
@@ -2,8 +2,8 @@ exec go test -v
 stdout 'PASS.*TestFoo'
 
 garble test -c
-bingrep bar.test$exe 'TestFoo' 'TestSeparateFoo'
-! bingrep bar.test$exe 'ImportedVar'
+binsubstr bar.test$exe 'TestFoo' 'TestSeparateFoo'
+! binsubstr bar.test$exe 'ImportedVar'
 
 exec ./bar.test -test.v
 stdout 'PASS.*TestFoo'