diff --git a/Makefile b/Makefile
index 63834a69..85075b3d 100644
--- a/Makefile
+++ b/Makefile
@@ -6,13 +6,14 @@ build:
 build-with-coverage:
 	go build -cover -ldflags "-s -w -X github.com/evilmartians/lefthook/internal/version.commit=$(COMMIT_HASH)" -o lefthook
 
+install: build
+	cp lefthook $(GOPATH)/bin/
+
 test:
 	go test -cpu 24 -race -count=1 -timeout=30s ./...
 
-test-integration: build-with-coverage
-	./lefthook dump
-	./lefthook dump --json
-	./lefthook dump --toml
+test-integrity: install
+	go test -cpu 24 -race -count=1 -timeout=30s -tags=integrity integrity_test.go
 
 bench:
 	go test -cpu 24 -race -run=Bench -bench=. ./...
diff --git a/internal/lefthook/runner/prepare_command.go b/internal/lefthook/runner/prepare_command.go
index aab1c231..67dbfe10 100644
--- a/internal/lefthook/runner/prepare_command.go
+++ b/internal/lefthook/runner/prepare_command.go
@@ -62,7 +62,7 @@ func (r *Runner) buildCommandArgs(command *config.Command) (*commandArgs, error,
 		},
 	}
 
-	filteredFiles := []string{}
+	filesFiltered := make([]string, 0)
 	runString := command.Run
 	for filesType, filesFn := range filesTypeToFn {
 		// Checking substitutions and skipping execution if it is empty.
@@ -79,28 +79,31 @@ func (r *Runner) buildCommandArgs(command *config.Command) (*commandArgs, error,
 				return nil, nil, errors.New("no files for inspection")
 			}
 
-			filesPrepared := prepareFiles(command, files)
-			if len(filesPrepared) == 0 {
+			filtered := filterFiles(command, files)
+			filesFiltered = append(filesFiltered, filtered...)
+
+			prepared := escapeFiles(filtered)
+			if len(prepared) == 0 {
 				return nil, nil, errors.New("no files for inspection")
 			}
-			filteredFiles = append(filteredFiles, filesPrepared...)
-			runString = replaceQuoted(runString, filesType, filesPrepared)
+
+			runString = replaceQuoted(runString, filesType, prepared)
 		}
 	}
 
-	if len(filteredFiles) == 0 && config.HookUsesStagedFiles(r.HookName) {
+	if len(filesFiltered) == 0 && config.HookUsesStagedFiles(r.HookName) {
 		files, err := r.Repo.StagedFiles()
 		if err == nil {
-			if len(prepareFiles(command, files)) == 0 {
+			if len(filterFiles(command, files)) == 0 {
 				return nil, nil, errors.New("no matching staged files")
 			}
 		}
 	}
 
-	if len(filteredFiles) == 0 && config.HookUsesPushFiles(r.HookName) {
+	if len(filesFiltered) == 0 && config.HookUsesPushFiles(r.HookName) {
 		files, err := r.Repo.PushFiles()
 		if err == nil {
-			if len(prepareFiles(command, files)) == 0 {
+			if len(filterFiles(command, files)) == 0 {
 				return nil, nil, errors.New("no matching push files")
 			}
 		}
@@ -111,7 +114,7 @@ func (r *Runner) buildCommandArgs(command *config.Command) (*commandArgs, error,
 	log.Debug("[lefthook] executing: ", runString)
 
 	return &commandArgs{
-		files: filteredFiles,
+		files: filesFiltered,
 		all:   strings.Split(runString, " "),
 	}, nil, nil
 }
@@ -124,7 +127,7 @@ func (r *Runner) replacePositionalArguments(runString string) string {
 	return runString
 }
 
-func prepareFiles(command *config.Command, files []string) []string {
+func filterFiles(command *config.Command, files []string) []string {
 	if files == nil {
 		return []string{}
 	}
@@ -137,7 +140,11 @@ func prepareFiles(command *config.Command, files []string) []string {
 
 	log.Debug("[lefthook] files after filters:\n", files)
 
-	// Escape file names to prevent unexpected bugs
+	return files
+}
+
+// Escape file names to prevent unexpected bugs.
+func escapeFiles(files []string) []string {
 	var filesEsc []string
 	for _, fileName := range files {
 		if len(fileName) > 0 {
diff --git a/internal/lefthook/runner/runner.go b/internal/lefthook/runner/runner.go
index 377c8c79..81d42388 100644
--- a/internal/lefthook/runner/runner.go
+++ b/internal/lefthook/runner/runner.go
@@ -372,13 +372,16 @@ func (r *Runner) runCommand(name string, command *config.Command) {
 
 	if finished && config.HookUsesStagedFiles(r.HookName) && command.StageFixed {
 		files := args.files
+
 		if len(files) == 0 {
-			stagedFiles, err := r.Repo.StagedFiles()
+			var err error
+			files, err = r.Repo.StagedFiles()
 			if err != nil {
 				log.Warn("Couldn't stage fixed files:", err)
 				return
 			}
-			files = prepareFiles(command, stagedFiles)
+
+			files = filterFiles(command, files)
 		}
 
 		if len(command.Root) > 0 {
diff --git a/testdata/stage_fixed.txt b/testdata/stage_fixed.txt
index 92257d70..fae06bf9 100644
--- a/testdata/stage_fixed.txt
+++ b/testdata/stage_fixed.txt
@@ -13,8 +13,13 @@ min_version: 1.1.1
 pre-commit:
   commands:
     edit_file:
-      run: echo newline >> file.txt
+      run: |
+        echo newline >> "[file].js"
+        echo newline >> file.txt
       stage_fixed: true
 
 -- file.txt --
-firstline
+sometext
+
+-- [file].js --
+somecode
diff --git a/testdata/stage_fixed_505.txt b/testdata/stage_fixed_505.txt
new file mode 100644
index 00000000..02c68926
--- /dev/null
+++ b/testdata/stage_fixed_505.txt
@@ -0,0 +1,19 @@
+exec git init
+exec lefthook install
+exec git config user.email "you@example.com"
+exec git config user.name "Your Name"
+exec git add -A
+exec git status --short
+exec git commit -m 'test stage_fixed'
+exec git status --short
+! stdout .
+
+-- lefthook.yml --
+pre-commit:
+  commands:
+    edit_file:
+      run: echo "{staged_files}" && echo newline >> "[file].js"
+      stage_fixed: true
+
+-- [file].js --
+somecode