diff --git a/__tests__/services/state.test.ts b/__tests__/services/state.test.ts
index a10fa6f..dafa2cf 100644
--- a/__tests__/services/state.test.ts
+++ b/__tests__/services/state.test.ts
@@ -1,6 +1,25 @@
 import { getMatchingFilePaths } from '../../src/services';
 import { Comment, Change, ChangeType } from '../../src/models';
 
+test('* matches everything', () => {
+  const comment: Comment = {
+    pathFilter: ['*'],
+    markdown: 'Woohoo!',
+    blocking: false
+  };
+
+  const changes: Change[] = [
+    {
+      file: 'app/models/foo.rb',
+      changeType: ChangeType.edit
+    }
+  ];
+
+  const result = getMatchingFilePaths(comment, changes);
+
+  expect(result).toEqual(changes.map(c => c.file));
+});
+
 test('match recursively', () => {
   const comment: Comment = {
     pathFilter: ['app/**'],
@@ -20,6 +39,25 @@ test('match recursively', () => {
   expect(result).toEqual(changes.map(c => c.file));
 });
 
+test('ignore case', () => {
+  const comment: Comment = {
+    pathFilter: ['app/**'],
+    markdown: 'Woohoo!',
+    blocking: false
+  };
+
+  const changes: Change[] = [
+    {
+      file: 'APP/MODELS/FOO.rb',
+      changeType: ChangeType.edit
+    }
+  ];
+
+  const result = getMatchingFilePaths(comment, changes);
+
+  expect(result).toEqual(changes.map(c => c.file));
+});
+
 test('remove exclusion patterns', () => {
   const comment: Comment = {
     pathFilter: ['app/**', '!app/models/*.h'],
@@ -107,3 +145,22 @@ test('match edited files only', () => {
 
   expect(result).toEqual(['app/models/old.rb']);
 });
+
+test('disallow multiple modifiers', () => {
+  const comment: Comment = {
+    pathFilter: ['!~app/**'],
+    markdown: 'Not edited files',
+    blocking: false
+  };
+
+  const changes: Change[] = [
+    {
+      file: 'app/models/old.rb',
+      changeType: ChangeType.edit
+    }
+  ];
+
+  expect(() => getMatchingFilePaths(comment, changes)).toThrow(
+    'Multiple path modifiers are not supported'
+  );
+});
diff --git a/package-lock.json b/package-lock.json
index 4421dd8..736e7d2 100644
--- a/package-lock.json
+++ b/package-lock.json
@@ -1,5 +1,5 @@
 {
-  "name": "typescript-action",
+  "name": "nitpicker",
   "version": "0.0.0",
   "lockfileVersion": 1,
   "requires": true,
diff --git a/src/services/state.ts b/src/services/state.ts
index 3d59ec5..1fddc95 100644
--- a/src/services/state.ts
+++ b/src/services/state.ts
@@ -12,6 +12,8 @@ import { getExistingComments } from '.';
 import { IOptions, Minimatch } from 'minimatch';
 import { Constants } from '../constants';
 
+const pathModifiers = ['!', '+', '-', '~'];
+
 export async function getTargetState(
   octokit: github.GitHub,
   allComments: Comment[],
@@ -91,6 +93,10 @@ export function getMatchingFilePaths(
     } else {
       inclusions.push(pathFilter);
     }
+
+    if (pathModifiers.includes(pathFilter[1])) {
+      throw new Error('Multiple path modifiers are not supported');
+    }
   }
 
   for (const change of changes) {