diff --git a/lib/copy-sync/__tests__/copy-sync-file.test.js b/lib/copy-sync/__tests__/copy-sync-file.test.js
index 5044214e..1218fce8 100644
--- a/lib/copy-sync/__tests__/copy-sync-file.test.js
+++ b/lib/copy-sync/__tests__/copy-sync-file.test.js
@@ -57,7 +57,7 @@ describe('+ copySync() / file', () => {
       const fileDest = path.join(TEST_DIR, 'TEST_fs-extra_copy')
       fs.writeFileSync(fileSrc, crypto.randomBytes(SIZE))
 
-      fs.chmodSync(fileSrc, parseInt('750', 8))
+      fs.chmodSync(fileSrc, 0o750)
       fs.copySync(fileSrc, fileDest)
 
       const statSrc = fs.statSync(fileSrc)
@@ -187,7 +187,7 @@ describe('+ copySync() / file', () => {
         describe('> when overwrite is true and dest is readonly', () => {
           it('should copy the file and not throw an error', () => {
             try {
-              fs.chmodSync(dest, parseInt('444', 8))
+              fs.chmodSync(dest, 0o444)
               fs.copySync(src, dest, { overwrite: true })
               destData = fs.readFileSync(dest, 'utf8')
               assert.strictEqual(srcData, destData)
diff --git a/lib/copy/__tests__/copy-permissions.test.js b/lib/copy/__tests__/copy-permissions.test.js
index ccc89cd2..f14bf023 100644
--- a/lib/copy/__tests__/copy-permissions.test.js
+++ b/lib/copy/__tests__/copy-permissions.test.js
@@ -8,10 +8,6 @@ const assert = require('assert')
 
 /* global beforeEach, describe, it */
 
-const o777 = parseInt('777', 8)
-const o666 = parseInt('666', 8)
-const o444 = parseInt('444', 8)
-
 describe('copy', () => {
   let TEST_DIR
 
@@ -27,8 +23,8 @@ describe('copy', () => {
     // var userid = require('userid')
 
     // http://man7.org/linux/man-pages/man2/stat.2.html
-    const S_IFREG = parseInt('0100000', 8) // regular file
-    const S_IFDIR = parseInt('0040000', 8) // directory
+    const S_IFREG = 0o100000 // regular file
+    const S_IFDIR = 0o40000 // directory
 
     // these are Mac specific I think (at least staff), should find Linux equivalent
     let gidWheel
@@ -54,31 +50,31 @@ describe('copy', () => {
 
     const f1 = path.join(srcDir, 'f1.txt')
     fs.writeFileSync(f1, '')
-    fs.chmodSync(f1, o666)
+    fs.chmodSync(f1, 0o666)
     fs.chownSync(f1, process.getuid(), gidWheel)
     const f1stats = fs.lstatSync(f1)
-    assert.strictEqual(f1stats.mode - S_IFREG, o666)
+    assert.strictEqual(f1stats.mode - S_IFREG, 0o666)
 
     const d1 = path.join(srcDir, 'somedir')
     fs.mkdirSync(d1)
-    fs.chmodSync(d1, o777)
+    fs.chmodSync(d1, 0o777)
     fs.chownSync(d1, process.getuid(), gidStaff)
     const d1stats = fs.lstatSync(d1)
-    assert.strictEqual(d1stats.mode - S_IFDIR, o777)
+    assert.strictEqual(d1stats.mode - S_IFDIR, 0o777)
 
     const f2 = path.join(d1, 'f2.bin')
     fs.writeFileSync(f2, '')
-    fs.chmodSync(f2, o777)
+    fs.chmodSync(f2, 0o777)
     fs.chownSync(f2, process.getuid(), gidStaff)
     const f2stats = fs.lstatSync(f2)
-    assert.strictEqual(f2stats.mode - S_IFREG, o777)
+    assert.strictEqual(f2stats.mode - S_IFREG, 0o777)
 
     const d2 = path.join(srcDir, 'crazydir')
     fs.mkdirSync(d2)
-    fs.chmodSync(d2, o444)
+    fs.chmodSync(d2, 0o444)
     fs.chownSync(d2, process.getuid(), gidWheel)
     const d2stats = fs.lstatSync(d2)
-    assert.strictEqual(d2stats.mode - S_IFDIR, o444)
+    assert.strictEqual(d2stats.mode - S_IFDIR, 0o444)
 
     const destDir = path.join(permDir, 'dest')
     fse.copy(srcDir, destDir, err => {
diff --git a/lib/copy/__tests__/ncp/ncp-error-perm.test.js b/lib/copy/__tests__/ncp/ncp-error-perm.test.js
index a31a43dd..49bef1f9 100644
--- a/lib/copy/__tests__/ncp/ncp-error-perm.test.js
+++ b/lib/copy/__tests__/ncp/ncp-error-perm.test.js
@@ -37,7 +37,7 @@ describe('ncp / error / dest-permission', () => {
     fse.outputFileSync(someFile, 'hello')
 
     fse.mkdirsSync(dest)
-    fs.chmodSync(dest, parseInt('444', 8))
+    fs.chmodSync(dest, 0o444)
 
     const subdest = path.join(dest, 'another-dir')
 
diff --git a/lib/mkdirs/__tests__/chmod.test.js b/lib/mkdirs/__tests__/chmod.test.js
index 19cb4019..5496427e 100644
--- a/lib/mkdirs/__tests__/chmod.test.js
+++ b/lib/mkdirs/__tests__/chmod.test.js
@@ -8,11 +8,6 @@ const assert = require('assert')
 
 /* global afterEach, beforeEach, describe, it */
 
-const o755 = parseInt('755', 8)
-const o744 = parseInt('744', 8)
-const o777 = parseInt('777', 8)
-const o666 = parseInt('666', 8)
-
 describe('mkdirp / chmod', () => {
   let TEST_DIR
   let TEST_SUBDIR
@@ -35,7 +30,7 @@ describe('mkdirp / chmod', () => {
   afterEach(done => fse.remove(TEST_DIR, done))
 
   it('chmod-pre', done => {
-    const mode = o744
+    const mode = 0o744
     fse.mkdirp(TEST_SUBDIR, mode, err => {
       assert.ifError(err, 'should not error')
       fs.stat(TEST_SUBDIR, (err, stat) => {
@@ -43,9 +38,9 @@ describe('mkdirp / chmod', () => {
         assert.ok(stat && stat.isDirectory(), 'should be directory')
 
         if (os.platform().indexOf('win') === 0) {
-          assert.strictEqual(stat && stat.mode & o777, o666, 'windows shit')
+          assert.strictEqual(stat && stat.mode & 0o777, 0o666, 'windows shit')
         } else {
-          assert.strictEqual(stat && stat.mode & o777, mode, 'should be 0744')
+          assert.strictEqual(stat && stat.mode & 0o777, mode, 'should be 0744')
         }
 
         done()
@@ -54,7 +49,7 @@ describe('mkdirp / chmod', () => {
   })
 
   it('chmod', done => {
-    const mode = o755
+    const mode = 0o755
     fse.mkdirp(TEST_SUBDIR, mode, err => {
       assert.ifError(err, 'should not error')
       fs.stat(TEST_SUBDIR, (err, stat) => {
diff --git a/lib/mkdirs/__tests__/clobber.test.js b/lib/mkdirs/__tests__/clobber.test.js
index f359cebf..b932b040 100644
--- a/lib/mkdirs/__tests__/clobber.test.js
+++ b/lib/mkdirs/__tests__/clobber.test.js
@@ -8,8 +8,6 @@ const assert = require('assert')
 
 /* global before, describe, it */
 
-const o755 = parseInt('755', 8)
-
 describe('mkdirp / clobber', () => {
   let TEST_DIR
   let file
@@ -42,7 +40,7 @@ describe('mkdirp / clobber', () => {
   })
 
   it('should clobber', done => {
-    fse.mkdirp(file, o755, err => {
+    fse.mkdirp(file, 0o755, err => {
       assert.ok(err)
       if (os.platform().indexOf('win') === 0) {
         assert.strictEqual(err.code, 'EEXIST')
diff --git a/lib/mkdirs/__tests__/mkdirp.test.js b/lib/mkdirs/__tests__/mkdirp.test.js
index 4ec42609..2af572a3 100644
--- a/lib/mkdirs/__tests__/mkdirp.test.js
+++ b/lib/mkdirs/__tests__/mkdirp.test.js
@@ -8,10 +8,6 @@ const assert = require('assert')
 
 /* global afterEach, beforeEach, describe, it */
 
-const o755 = parseInt('755', 8)
-const o777 = parseInt('777', 8)
-const o666 = parseInt('666', 8)
-
 describe('mkdirp / mkdirp', () => {
   let TEST_DIR
 
@@ -29,7 +25,7 @@ describe('mkdirp / mkdirp', () => {
 
     const file = path.join(TEST_DIR, x, y, z)
 
-    fse.mkdirp(file, o755, err => {
+    fse.mkdirp(file, 0o755, err => {
       assert.ifError(err)
       fse.pathExists(file, (err, ex) => {
         assert.ifError(err)
@@ -38,9 +34,9 @@ describe('mkdirp / mkdirp', () => {
           assert.ifError(err)
 
           if (os.platform().indexOf('win') === 0) {
-            assert.strictEqual(stat.mode & o777, o666)
+            assert.strictEqual(stat.mode & 0o777, 0o666)
           } else {
-            assert.strictEqual(stat.mode & o777, o755)
+            assert.strictEqual(stat.mode & 0o777, 0o755)
           }
 
           assert.ok(stat.isDirectory(), 'target not a directory')
diff --git a/lib/mkdirs/__tests__/perm.test.js b/lib/mkdirs/__tests__/perm.test.js
index 8aa0743b..b883a652 100644
--- a/lib/mkdirs/__tests__/perm.test.js
+++ b/lib/mkdirs/__tests__/perm.test.js
@@ -8,10 +8,6 @@ const assert = require('assert')
 
 /* global afterEach, beforeEach, describe, it */
 
-const o755 = parseInt('755', 8)
-const o777 = parseInt('777', 8)
-const o666 = parseInt('666', 8)
-
 describe('mkdirp / perm', () => {
   let TEST_DIR
 
@@ -25,7 +21,7 @@ describe('mkdirp / perm', () => {
   it('async perm', done => {
     const file = path.join(TEST_DIR, (Math.random() * (1 << 30)).toString(16))
 
-    fse.mkdirp(file, o755, err => {
+    fse.mkdirp(file, 0o755, err => {
       assert.ifError(err)
       fse.pathExists(file, (err, ex) => {
         assert.ifError(err)
@@ -34,9 +30,9 @@ describe('mkdirp / perm', () => {
           assert.ifError(err)
 
           if (os.platform().indexOf('win') === 0) {
-            assert.strictEqual(stat.mode & o777, o666)
+            assert.strictEqual(stat.mode & 0o777, 0o666)
           } else {
-            assert.strictEqual(stat.mode & o777, o755)
+            assert.strictEqual(stat.mode & 0o777, 0o755)
           }
 
           assert.ok(stat.isDirectory(), 'target not a directory')
@@ -47,7 +43,7 @@ describe('mkdirp / perm', () => {
   })
 
   it('async root perm', done => {
-    fse.mkdirp(path.join(os.tmpdir(), 'tmp'), o755, err => {
+    fse.mkdirp(path.join(os.tmpdir(), 'tmp'), 0o755, err => {
       assert.ifError(err)
       done()
     })
diff --git a/lib/mkdirs/__tests__/perm_sync.test.js b/lib/mkdirs/__tests__/perm_sync.test.js
index 27b475e8..2c75967c 100644
--- a/lib/mkdirs/__tests__/perm_sync.test.js
+++ b/lib/mkdirs/__tests__/perm_sync.test.js
@@ -8,10 +8,6 @@ const assert = require('assert')
 
 /* global afterEach, beforeEach, describe, it */
 
-const o755 = parseInt('755', 8)
-const o777 = parseInt('777', 8)
-const o666 = parseInt('666', 8)
-
 describe('mkdirp / perm_sync', () => {
   let TEST_DIR
 
@@ -25,7 +21,7 @@ describe('mkdirp / perm_sync', () => {
   it('sync perm', done => {
     const file = path.join(TEST_DIR, (Math.random() * (1 << 30)).toString(16) + '.json')
 
-    fse.mkdirpSync(file, o755)
+    fse.mkdirpSync(file, 0o755)
     fse.pathExists(file, (err, ex) => {
       assert.ifError(err)
       assert.ok(ex, 'file created')
@@ -33,9 +29,9 @@ describe('mkdirp / perm_sync', () => {
         assert.ifError(err)
 
         if (os.platform().indexOf('win') === 0) {
-          assert.strictEqual(stat.mode & o777, o666)
+          assert.strictEqual(stat.mode & 0o777, 0o666)
         } else {
-          assert.strictEqual(stat.mode & o777, o755)
+          assert.strictEqual(stat.mode & 0o777, 0o755)
         }
 
         assert.ok(stat.isDirectory(), 'target not a directory')
@@ -46,7 +42,7 @@ describe('mkdirp / perm_sync', () => {
 
   it('sync root perm', done => {
     const file = TEST_DIR
-    fse.mkdirpSync(file, o755)
+    fse.mkdirpSync(file, 0o755)
     fse.pathExists(file, (err, ex) => {
       assert.ifError(err)
       assert.ok(ex, 'file created')
diff --git a/lib/mkdirs/__tests__/race.test.js b/lib/mkdirs/__tests__/race.test.js
index 611d10fc..1d075f46 100644
--- a/lib/mkdirs/__tests__/race.test.js
+++ b/lib/mkdirs/__tests__/race.test.js
@@ -8,10 +8,6 @@ const assert = require('assert')
 
 /* global afterEach, beforeEach, describe, it */
 
-const o755 = parseInt('755', 8)
-const o777 = parseInt('777', 8)
-const o666 = parseInt('666', 8)
-
 describe('mkdirp / race', () => {
   let TEST_DIR
   let file
@@ -42,7 +38,7 @@ describe('mkdirp / race', () => {
     mk(file, () => --res === 0 ? done() : undefined)
 
     function mk (file, callback) {
-      fse.mkdirp(file, o755, err => {
+      fse.mkdirp(file, 0o755, err => {
         assert.ifError(err)
         fse.pathExists(file, (err, ex) => {
           assert.ifError(err)
@@ -51,9 +47,9 @@ describe('mkdirp / race', () => {
             assert.ifError(err)
 
             if (os.platform().indexOf('win') === 0) {
-              assert.strictEqual(stat.mode & o777, o666)
+              assert.strictEqual(stat.mode & 0o777, 0o666)
             } else {
-              assert.strictEqual(stat.mode & o777, o755)
+              assert.strictEqual(stat.mode & 0o777, 0o755)
             }
 
             assert.ok(stat.isDirectory(), 'target not a directory')
diff --git a/lib/mkdirs/__tests__/rel.test.js b/lib/mkdirs/__tests__/rel.test.js
index 837e1e6b..bb00031e 100644
--- a/lib/mkdirs/__tests__/rel.test.js
+++ b/lib/mkdirs/__tests__/rel.test.js
@@ -10,10 +10,6 @@ const assert = require('assert')
 
 /* global afterEach, beforeEach, describe, it */
 
-const o755 = parseInt('755', 8)
-const o777 = parseInt('777', 8)
-const o666 = parseInt('666', 8)
-
 describe('mkdirp / relative', () => {
   let TEST_DIR
   let file
@@ -39,7 +35,7 @@ describe('mkdirp / relative', () => {
   it('should make the directory with relative path', done => {
     process.chdir(TEST_DIR)
 
-    fse.mkdirp(file, o755, err => {
+    fse.mkdirp(file, 0o755, err => {
       assert.ifError(err)
       fse.pathExists(file, (err, ex) => {
         assert.ifError(err)
@@ -50,9 +46,9 @@ describe('mkdirp / relative', () => {
           process.chdir(CWD)
 
           if (os.platform().indexOf('win') === 0) {
-            assert.strictEqual(stat.mode & o777, o666)
+            assert.strictEqual(stat.mode & 0o777, 0o666)
           } else {
-            assert.strictEqual(stat.mode & o777, o755)
+            assert.strictEqual(stat.mode & 0o777, 0o755)
           }
 
           assert.ok(stat.isDirectory(), 'target not a directory')
diff --git a/lib/mkdirs/__tests__/root.test.js b/lib/mkdirs/__tests__/root.test.js
index ee49c39d..2d0974de 100644
--- a/lib/mkdirs/__tests__/root.test.js
+++ b/lib/mkdirs/__tests__/root.test.js
@@ -7,8 +7,6 @@ const assert = require('assert')
 
 /* global describe, it */
 
-const o755 = parseInt('755', 8)
-
 describe('mkdirp / root', () => {
   // '/' on unix, 'c:/' on windows.
   const dir = path.normalize(path.resolve(path.sep)).toLowerCase()
@@ -17,7 +15,7 @@ describe('mkdirp / root', () => {
   if (process.platform === 'win32' && (dir.indexOf('c:\\') === -1) && (dir.indexOf('d:\\') === -1)) return
 
   it('should', done => {
-    fse.mkdirp(dir, o755, err => {
+    fse.mkdirp(dir, 0o755, err => {
       if (err) throw err
       fs.stat(dir, (er, stat) => {
         if (er) throw er
diff --git a/lib/mkdirs/__tests__/sync.test.js b/lib/mkdirs/__tests__/sync.test.js
index 0652333a..1b7fe092 100644
--- a/lib/mkdirs/__tests__/sync.test.js
+++ b/lib/mkdirs/__tests__/sync.test.js
@@ -8,10 +8,6 @@ const assert = require('assert')
 
 /* global afterEach, beforeEach, describe, it */
 
-const o755 = parseInt('755', 8)
-const o777 = parseInt('777', 8)
-const o666 = parseInt('666', 8)
-
 describe('mkdirp / sync', () => {
   let TEST_DIR
   let file
@@ -35,7 +31,7 @@ describe('mkdirp / sync', () => {
 
   it('should', done => {
     try {
-      fse.mkdirpSync(file, o755)
+      fse.mkdirpSync(file, 0o755)
     } catch (err) {
       assert.fail(err)
     }
@@ -47,9 +43,9 @@ describe('mkdirp / sync', () => {
         assert.ifError(err)
         // http://stackoverflow.com/questions/592448/c-how-to-set-file-permissions-cross-platform
         if (os.platform().indexOf('win') === 0) {
-          assert.strictEqual(stat.mode & o777, o666)
+          assert.strictEqual(stat.mode & 0o777, 0o666)
         } else {
-          assert.strictEqual(stat.mode & o777, o755)
+          assert.strictEqual(stat.mode & 0o777, 0o755)
         }
 
         assert.ok(stat.isDirectory(), 'target not a directory')
diff --git a/lib/mkdirs/__tests__/umask.test.js b/lib/mkdirs/__tests__/umask.test.js
index 6049dccc..e911dbc5 100644
--- a/lib/mkdirs/__tests__/umask.test.js
+++ b/lib/mkdirs/__tests__/umask.test.js
@@ -8,8 +8,6 @@ const fse = require('../../')
 
 /* global afterEach, beforeEach, describe, it */
 
-const o777 = parseInt('777', 8)
-
 describe('mkdirp', () => {
   let TEST_DIR
   let _rndDir
@@ -47,7 +45,7 @@ describe('mkdirp', () => {
             assert.ok(ex, 'file created')
             fs.stat(_rndDir, (err, stat) => {
               assert.ifError(err)
-              assert.strictEqual(stat.mode & o777, o777 & (~process.umask()))
+              assert.strictEqual(stat.mode & 0o777, 0o777 & (~process.umask()))
               assert.ok(stat.isDirectory(), 'target not a directory')
               done()
             })
@@ -71,7 +69,7 @@ describe('mkdirp', () => {
           assert.ok(ex, 'file created')
           fs.stat(_rndDir, (err, stat) => {
             assert.ifError(err)
-            assert.strictEqual(stat.mode & o777, (o777 & (~process.umask())))
+            assert.strictEqual(stat.mode & 0o777, (0o777 & (~process.umask())))
             assert.ok(stat.isDirectory(), 'target not a directory')
             done()
           })
diff --git a/lib/mkdirs/mkdirs-sync.js b/lib/mkdirs/mkdirs-sync.js
index a34acb99..25d794e2 100644
--- a/lib/mkdirs/mkdirs-sync.js
+++ b/lib/mkdirs/mkdirs-sync.js
@@ -4,8 +4,6 @@ const fs = require('graceful-fs')
 const path = require('path')
 const invalidWin32Path = require('./win32').invalidWin32Path
 
-const o777 = parseInt('0777', 8)
-
 function mkdirsSync (p, opts, made) {
   if (!opts || typeof opts !== 'object') {
     opts = { mode: opts }
@@ -21,7 +19,7 @@ function mkdirsSync (p, opts, made) {
   }
 
   if (mode === undefined) {
-    mode = o777 & (~process.umask())
+    mode = 0o777 & (~process.umask())
   }
   if (!made) made = null
 
diff --git a/lib/mkdirs/mkdirs.js b/lib/mkdirs/mkdirs.js
index 18975337..9c72dc91 100644
--- a/lib/mkdirs/mkdirs.js
+++ b/lib/mkdirs/mkdirs.js
@@ -4,8 +4,6 @@ const fs = require('graceful-fs')
 const path = require('path')
 const invalidWin32Path = require('./win32').invalidWin32Path
 
-const o777 = parseInt('0777', 8)
-
 function mkdirs (p, opts, callback, made) {
   if (typeof opts === 'function') {
     callback = opts
@@ -24,7 +22,7 @@ function mkdirs (p, opts, callback, made) {
   const xfs = opts.fs || fs
 
   if (mode === undefined) {
-    mode = o777 & (~process.umask())
+    mode = 0o777 & (~process.umask())
   }
   if (!made) made = null