diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index dc4ee7e0..e39f0e9e 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -13,10 +13,11 @@ jobs:
     runs-on: ${{ matrix.os }}
     strategy:
       matrix:
-        os: [macos-latest, macos-11.0, ubuntu-latest]
+        os: [macos-latest, ubuntu-latest]
         go-version: [1.17.6]
+        shell: [/bin/bash, /bin/zsh]
 
-    name: ${{ matrix.os }} / go-${{ matrix.go-version }}
+    name: ${{ matrix.os }} / go-${{ matrix.go-version }} / ${{ matrix.shell }}
     steps:
       - uses: actions/setup-go@v1
         with:
@@ -30,6 +31,9 @@ jobs:
 
       - uses: actions/checkout@v2
 
+      - if: contains(matrix.os, 'ubuntu')
+        run: sudo apt install zsh
+
       - if: contains(matrix.os, 'macos')
         run: |
           sw_vers
@@ -40,6 +44,8 @@ jobs:
       - run: go mod download
 
       - run: go test -v -race -coverprofile=coverage.out -covermode=atomic -timeout=300s ./...
+        env:
+          SHELL: ${{ matrix.shell }}
 
   devel-release:
     runs-on: macos-latest
diff --git a/dev/app.go b/dev/app.go
index 955ddc68..2c799ee3 100644
--- a/dev/app.go
+++ b/dev/app.go
@@ -24,8 +24,6 @@ import (
 	"gopkg.in/tomb.v2"
 )
 
-const DefaultThreads = 5
-
 var ErrUnexpectedExit = errors.New("unexpected exit")
 
 type App struct {
@@ -49,10 +47,6 @@ type App struct {
 	pool    *AppPool
 	lastUse time.Time
 
-	lock sync.Mutex
-
-	booting bool
-
 	readyChan chan struct{}
 }
 
@@ -133,7 +127,7 @@ func (a *App) watch() error {
 	reason := "detected interval shutdown"
 
 	select {
-	case err = <-c:
+	case <-c:
 		reason = "stdout/stderr closed"
 		err = fmt.Errorf("%s:\n\t%s", ErrUnexpectedExit, a.lastLogLine)
 	case <-a.t.Dying():
@@ -237,64 +231,24 @@ func (a *App) Log() string {
 	return buf.String()
 }
 
-const executionShell = `exec bash -c '
-cd %s
-
-if test -e ~/.powconfig && [ "$PUMADEV_SOURCE_POWCONFIG" != "0" ]; then
-	source ~/.powconfig
-fi
-
-if test -e .env && [ "$PUMADEV_SOURCE_ENV" != "0" ]; then
-	source .env
-fi
-
-if test -e .powrc && [ "$PUMADEV_SOURCE_POWRC" != "0" ]; then
-	source .powrc
-fi
-
-if test -e .powenv && [ "$PUMADEV_SOURCE_POWENV" != "0" ]; then
-	source .powenv
-fi
-
-if test -e .pumaenv && [ "$PUMADEV_SOURCE_PUMAENV" != "0" ]; then
-	source .pumaenv
-fi
-
-if test -e Gemfile && bundle exec puma -V &>/dev/null; then
-	exec bundle exec puma -C $CONFIG --tag puma-dev:%s -w $WORKERS -t 0:$THREADS -b unix:%s
-fi
-
-exec puma -C $CONFIG --tag puma-dev:%s -w $WORKERS -t 0:$THREADS -b unix:%s'
-`
-
 func (pool *AppPool) LaunchApp(name, dir string) (*App, error) {
-	tmpDir := filepath.Join(dir, "tmp")
-	err := os.MkdirAll(tmpDir, 0755)
-	if err != nil {
+	appDir, dirErr := filepath.EvalSymlinks(dir)
+	if dirErr != nil {
+		return nil, dirErr
+	}
+
+	tmpDir := filepath.Join(appDir, "tmp")
+	if err := os.MkdirAll(tmpDir, 0755); err != nil {
 		return nil, err
 	}
 
 	socket := filepath.Join(tmpDir, fmt.Sprintf("puma-dev-%d.sock", os.Getpid()))
 
-	shell := os.Getenv("SHELL")
-
-	if shell == "" {
-		fmt.Printf("! SHELL env var not set, using /bin/bash by default")
-		shell = "/bin/bash"
+	cmd, err := BuildPumaCommand(name, socket, appDir)
+	if err != nil {
+		return nil, err
 	}
 
-	cmd := exec.Command(shell, "-l", "-i", "-c",
-		fmt.Sprintf(executionShell, dir, name, socket, name, socket))
-
-	cmd.Dir = dir
-
-	cmd.Env = os.Environ()
-	cmd.Env = append(cmd.Env,
-		fmt.Sprintf("THREADS=%d", DefaultThreads),
-		"WORKERS=0",
-		"CONFIG=-",
-	)
-
 	stdout, err := cmd.StdoutPipe()
 	if err != nil {
 		return nil, err
@@ -314,7 +268,7 @@ func (pool *AppPool) LaunchApp(name, dir string) (*App, error) {
 		Command:   cmd,
 		Events:    pool.Events,
 		stdout:    stdout,
-		dir:       dir,
+		dir:       appDir,
 		pool:      pool,
 		readyChan: make(chan struct{}),
 		lastUse:   time.Now(),
@@ -322,7 +276,7 @@ func (pool *AppPool) LaunchApp(name, dir string) (*App, error) {
 
 	app.eventAdd("booting_app", "socket", socket)
 
-	stat, err := os.Stat(filepath.Join(dir, "public"))
+	stat, err := os.Stat(filepath.Join(appDir, "public"))
 	if err == nil {
 		app.Public = stat.IsDir()
 	}
@@ -639,3 +593,81 @@ func (a *AppPool) Purge() {
 
 	a.Events.Add("apps_purged")
 }
+
+const pumaShellScriptTemplate = `exec %s -c '
+cd %s
+
+if test -e ~/.powconfig && [ "$PUMADEV_SOURCE_POWCONFIG" != "0" ]; then
+  source ~/.powconfig
+fi
+
+if test -e ~/.pumaenv && [ "$PUMADEV_SOURCE_HOME_PUMAENV" != "0" ]; then
+  source ~/.pumaenv
+fi
+
+if test -e .env && [ "$PUMADEV_SOURCE_ENV" != "0" ]; then
+  source .env
+fi
+
+if test -e .powrc && [ "$PUMADEV_SOURCE_POWRC" != "0" ]; then
+  source .powrc
+fi
+
+if test -e .powenv && [ "$PUMADEV_SOURCE_POWENV" != "0" ]; then
+  source .powenv
+fi
+
+if test -e .pumaenv && [ "$PUMADEV_SOURCE_PUMAENV" != "0" ]; then
+  source .pumaenv
+fi
+
+if test -e Gemfile && bundle exec puma -V &>/dev/null; then
+  exec bundle exec puma %s
+fi
+
+exec puma %s
+'` // <-- don't forget this closing quote
+
+func BuildPumaCommand(appName string, socketPath string, appDir string) (*exec.Cmd, error) {
+
+	osMapEnv := GetMapEnviron()
+
+	// This environment will be fed into the puma exec shell.
+	// However, we _also_ source each supported env file inside the shell to allow for
+	// custom environment grooming.
+	var mapEnv map[string]string
+	mapEnv, err := LoadEnv(osMapEnv, appDir)
+	if err != nil {
+		fmt.Printf("! Falling back to default environment. %v\n", err.Error())
+		mapEnv = osMapEnv
+	}
+
+	pumaArgs := fmt.Sprintf("--tag puma-dev:%s -b unix:%s", appName, socketPath)
+
+	if workers, exist := mapEnv["WORKERS"]; exist {
+		pumaArgs = fmt.Sprintf("-w%s %s", workers, pumaArgs)
+	}
+
+	if threads, exist := mapEnv["THREADS"]; exist {
+		pumaArgs = fmt.Sprintf("-t0:%s %s", threads, pumaArgs)
+	}
+
+	if config, exist := mapEnv["CONFIG"]; exist {
+		pumaArgs = fmt.Sprintf("-C%s %s", config, pumaArgs)
+	}
+
+	// use SHELL from OS env or app env
+	execShell := mapEnv["SHELL"]
+	if execShell == "" {
+		fmt.Printf("! SHELL env var not set, using /bin/bash by default\n")
+		execShell = "/bin/bash"
+	}
+
+	script := fmt.Sprintf(pumaShellScriptTemplate, execShell, appDir, pumaArgs, pumaArgs)
+
+	cmd := exec.Command(execShell, "-l", "-i", "-c", script)
+	cmd.Dir = appDir
+	cmd.Env = ToCmdEnv(mapEnv)
+
+	return cmd, nil
+}
diff --git a/dev/app_test.go b/dev/app_test.go
new file mode 100644
index 00000000..6acd774a
--- /dev/null
+++ b/dev/app_test.go
@@ -0,0 +1,27 @@
+package dev
+
+import (
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+)
+
+func TestBuildPumaCommand_withEnv(t *testing.T) {
+	t.Setenv("CONFIG", "-")
+	t.Setenv("WORKERS", "4")
+	t.Setenv("THREADS", "5")
+
+	cmd, _ := BuildPumaCommand("foo", "/tmp/tmp/foo.sock", "/tmp")
+
+	assert.Regexp(t, " -w4 ", cmd.Args[4])
+	assert.Regexp(t, " -t0:5 ", cmd.Args[4])
+	assert.Regexp(t, " -C- ", cmd.Args[4])
+}
+
+func TestBuildPumaCommand_withoutEnv(t *testing.T) {
+	cmd, _ := BuildPumaCommand("foo", "/tmp/tmp/foo.sock", "/tmp")
+
+	assert.NotRegexp(t, " -w", cmd.Args[4])
+	assert.NotRegexp(t, " -t", cmd.Args[4])
+	assert.NotRegexp(t, " -C", cmd.Args[4])
+}
diff --git a/dev/env.go b/dev/env.go
new file mode 100644
index 00000000..62b73219
--- /dev/null
+++ b/dev/env.go
@@ -0,0 +1,74 @@
+package dev
+
+import (
+	"fmt"
+	"os"
+	"path/filepath"
+	"strings"
+
+	"github.com/joho/godotenv"
+	"github.com/puma/puma-dev/homedir"
+)
+
+// `.pumaenv` has highest priority, `~/.powconfig` has lowest.
+// Be sure to keep these in sync with the pumaShellScriptTemplate in app.go
+var AppEnvPaths = []string{".env", ".powrc", ".powenv", ".pumaenv"}
+var HomeEnvPaths = []string{"~/.powconfig", "~/.pumaenv"}
+
+func LoadEnv(baseEnv map[string]string, dir string) (envMap map[string]string, err error) {
+	// build a list of all the supported env files that exist on the filesystem to load
+	var envPaths []string
+
+	for _, path := range AppEnvPaths {
+		fullPath := filepath.Join(dir, path)
+		if _, err := os.Stat(fullPath); err == nil {
+			envPaths = append(envPaths, fullPath)
+		}
+	}
+
+	for _, path := range HomeEnvPaths {
+		if fullPath, err := homedir.Expand(path); err == nil {
+			if _, err := os.Stat(fullPath); err == nil {
+				envPaths = append(envPaths, fullPath)
+			}
+		}
+	}
+
+	envMap = baseEnv
+
+	// if we have any optional env paths to source, source them
+	if len(envPaths) > 0 {
+		// load the env into a map
+		appEnv, err := godotenv.Read(envPaths...)
+		if err != nil {
+			// if any path fails to load, bail out.
+			return nil, fmt.Errorf("%v in %v", err, envPaths)
+		}
+
+		// merge contents from appEnv into envMap
+		// this way dotenv values will supersede os env values
+		for k, v := range appEnv {
+			envMap[k] = v
+		}
+	}
+
+	return
+}
+
+func ToCmdEnv(envMap map[string]string) (env []string) {
+	for k, v := range envMap {
+		env = append(env, fmt.Sprintf("%s=%s", k, v))
+	}
+	return
+}
+
+func GetMapEnviron() (envMap map[string]string) {
+	envMap = make(map[string]string)
+
+	for _, keyval := range os.Environ() {
+		pair := strings.Split(keyval, "=")
+		envMap[pair[0]] = pair[1]
+	}
+
+	return
+}
diff --git a/dev/env_test.go b/dev/env_test.go
new file mode 100644
index 00000000..fbf94335
--- /dev/null
+++ b/dev/env_test.go
@@ -0,0 +1,75 @@
+package dev
+
+import (
+	"io/fs"
+	"io/ioutil"
+	"os"
+	"path/filepath"
+	"testing"
+
+	"github.com/puma/puma-dev/homedir"
+	"github.com/stretchr/testify/assert"
+)
+
+func TestLoadEnv_shellScript(t *testing.T) {
+	base := make(map[string]string)
+	appDir, _ := os.MkdirTemp("/tmp", "TestLoadEnv_fileEnvPriority")
+
+	// if an env file contains more than just variables, we'll bail out
+	// and fall back to default behavior
+	ioutil.WriteFile(filepath.Join(appDir, ".powrc"), []byte(`function puma-dev-test () { echo 'hi puma'; }`), fs.FileMode(0600))
+
+	_, err := LoadEnv(base, appDir)
+
+	assert.Error(t, err)
+}
+
+func TestLoadEnv_fileEnvPriority(t *testing.T) {
+	base := make(map[string]string)
+	appDir, _ := os.MkdirTemp("/tmp", "TestLoadEnv_fileEnvPriority")
+
+	ioutil.WriteFile(filepath.Join(appDir, ".pumaenv"), []byte("FILE=.pumaenv"), fs.FileMode(0600))
+	ioutil.WriteFile(filepath.Join(appDir, ".powenv"), []byte("FILE=.powenv"), fs.FileMode(0600))
+	ioutil.WriteFile(filepath.Join(appDir, ".powrc"), []byte("FILE=.powrc"), fs.FileMode(0600))
+	ioutil.WriteFile(filepath.Join(appDir, ".env"), []byte("FILE=.env"), fs.FileMode(0600))
+
+	res, _ := LoadEnv(base, appDir)
+
+	assert.Equal(t, res["FILE"], ".pumaenv")
+}
+
+func TestLoadEnv_homedirFileEnv(t *testing.T) {
+	if os.Getenv("CI") != "true" {
+		t.Skip("Skipping LoadEnv homedir tests outside CI")
+	}
+
+	base := make(map[string]string)
+	appDir, _ := os.MkdirTemp("/tmp", "TestLoadEnv_homedirFileEnv")
+
+	powconfig := homedir.MustExpand("~/.powconfig")
+	pumaenv := homedir.MustExpand("~/.pumaenv")
+
+	ioutil.WriteFile(powconfig, []byte("FILE=~/.powconfig"), fs.FileMode(0600))
+	ioutil.WriteFile(pumaenv, []byte("FILE=~/.pumaenv"), fs.FileMode(0600))
+
+	defer func() {
+		os.Remove(powconfig)
+		os.Remove(pumaenv)
+	}()
+
+	res, _ := LoadEnv(base, appDir)
+
+	assert.Equal(t, res["FILE"], "~/.pumaenv")
+
+}
+
+func TestLoadEnv(t *testing.T) {
+	t.Setenv("FILE", "environment")
+
+	base := GetMapEnviron()
+	appDir, _ := os.MkdirTemp("/tmp", "TestLoadEnv")
+
+	res, _ := LoadEnv(base, appDir)
+
+	assert.Equal(t, res["FILE"], "environment")
+}
diff --git a/dev/ssl_darwin.go b/dev/ssl_darwin.go
index 129ff77a..ba3480c3 100644
--- a/dev/ssl_darwin.go
+++ b/dev/ssl_darwin.go
@@ -36,7 +36,7 @@ func TrustCert(cert string) error {
 
 func DeleteAllPumaDevCAFromDefaultKeychain() error {
 	deleteAllBashCommand := `
-	for sha in $(security find-certificate -a -c "Puma-dev CA" -Z | awk '/SHA-1/ {print $3}'); do 
+	for sha in $(security find-certificate -a -c "Puma-dev CA" -Z | awk '/SHA-1/ {print $3}'); do
 		security delete-certificate -t -Z $sha || security delete-certificate -Z $sha
 	done
 	`
@@ -65,5 +65,5 @@ func loginKeyChain() (string, error) {
 		return "", fmt.Errorf("could not find login keychain. security login-keychain had %s, %s", err.Error(), stderr.Bytes())
 	}
 
-	return string(stdout.Bytes()), nil
+	return stdout.String(), nil
 }
diff --git a/go.mod b/go.mod
index 137be06a..ce9cb95d 100644
--- a/go.mod
+++ b/go.mod
@@ -5,15 +5,15 @@ go 1.13
 require (
 	github.com/avast/retry-go v2.5.0+incompatible
 	github.com/bmizerany/pat v0.0.0-20170815010413-6226ea591a40
+	github.com/davecgh/go-spew v1.1.1 // indirect
 	github.com/fsnotify/fsevents v0.1.1
 	github.com/fsnotify/fsnotify v1.4.9
 	github.com/hashicorp/golang-lru v0.5.4
+	github.com/joho/godotenv v1.4.0
 	github.com/kardianos/osext v0.0.0-20190222173326-2bc1f35cddc0
 	github.com/miekg/dns v1.1.29
-	github.com/stretchr/objx v0.2.0 // indirect
 	github.com/stretchr/testify v1.5.1
 	github.com/vektra/errors v0.0.0-20140903201135-c64d83aba85a
-	github.com/vektra/neko v0.0.0-20141017182438-843f5ecf6932
 	golang.org/x/crypto v0.0.0-20200403201458-baeed622b8d8 // indirect
 	golang.org/x/net v0.0.0-20200324143707-d3edc9973b7e // indirect
 	golang.org/x/sys v0.0.0-20200331124033-c3d80250170d // indirect
diff --git a/go.sum b/go.sum
index 3e8c7a7f..48ac0dd3 100644
--- a/go.sum
+++ b/go.sum
@@ -11,6 +11,8 @@ github.com/fsnotify/fsnotify v1.4.9 h1:hsms1Qyu0jgnwNXIxa+/V/PDsU6CfLf6CNO8H7IWo
 github.com/fsnotify/fsnotify v1.4.9/go.mod h1:znqG4EE+3YCdAaPaxE2ZRY/06pZUdp0tY4IgpuI1SZQ=
 github.com/hashicorp/golang-lru v0.5.4 h1:YDjusn29QI/Das2iO9M0BHnIbxPeyuCHsjMW+lJfyTc=
 github.com/hashicorp/golang-lru v0.5.4/go.mod h1:iADmTwqILo4mZ8BN3D2Q6+9jd8WM5uGBxy+E8yxSoD4=
+github.com/joho/godotenv v1.4.0 h1:3l4+N6zfMWnkbPEXKng2o2/MR5mSwTrBih4ZEkkz1lg=
+github.com/joho/godotenv v1.4.0/go.mod h1:f4LDr5Voq0i2e/R5DDNOoa2zzDfwtkZa6DnEwAbqwq4=
 github.com/kardianos/osext v0.0.0-20190222173326-2bc1f35cddc0 h1:iQTw/8FWTuc7uiaSepXwyf3o52HaUYcV+Tu66S3F5GA=
 github.com/kardianos/osext v0.0.0-20190222173326-2bc1f35cddc0/go.mod h1:1NbS8ALrpOvjt0rHPNLyCIeMtbizbir8U//inJ+zuB8=
 github.com/miekg/dns v1.1.29 h1:xHBEhR+t5RzcFJjBLJlax2daXOrTYtr9z4WdKEfWFzg=
@@ -18,15 +20,10 @@ github.com/miekg/dns v1.1.29/go.mod h1:KNUDUusw/aVsxyTYZM1oqvCicbwhgbNgztCETuNZ7
 github.com/pmezard/go-difflib v1.0.0 h1:4DBwDE0NGyQoBHbLQYPwSUPoCMWR5BEzIk/f1lZbAQM=
 github.com/pmezard/go-difflib v1.0.0/go.mod h1:iKH77koFhYxTK1pcRnkKkqfTogsbg7gZNVY4sRDYZ/4=
 github.com/stretchr/objx v0.1.0/go.mod h1:HFkY916IF+rwdDfMAkV7OtwuqBVzrE8GR6GFx+wExME=
-github.com/stretchr/objx v0.2.0 h1:Hbg2NidpLE8veEBkEZTL3CvlkUIVzuU9jDplZO54c48=
-github.com/stretchr/objx v0.2.0/go.mod h1:qt09Ya8vawLte6SNmTgCsAVtYtaKzEcn8ATUoHMkEqE=
-github.com/stretchr/testify v1.3.0/go.mod h1:M5WIy9Dh21IEIfnGCwXGc5bZfKNJtfHm1UVUgZn+9EI=
 github.com/stretchr/testify v1.5.1 h1:nOGnQDM7FYENwehXlg/kFVnos3rEvtKTjRvOWSzb6H4=
 github.com/stretchr/testify v1.5.1/go.mod h1:5W2xD1RspED5o8YsWQXVCued0rvSQ+mT+I5cxcmMvtA=
 github.com/vektra/errors v0.0.0-20140903201135-c64d83aba85a h1:lUVfiMMY/te9icPKBqOKkBIMZNxSpM90dxokDeCcfBg=
 github.com/vektra/errors v0.0.0-20140903201135-c64d83aba85a/go.mod h1:KUxJS71XlMs+ztT+RzsLRoWUQRUpECo/+Rb0EBk8/Wc=
-github.com/vektra/neko v0.0.0-20141017182438-843f5ecf6932 h1:SslNPzxMsvmq9d29joAV87uY34VPgN0W9CDIcztcipg=
-github.com/vektra/neko v0.0.0-20141017182438-843f5ecf6932/go.mod h1:7tfPLehrsToaevw9Vi9iL6FOslcBJ/uqYQc8y3YIbdI=
 golang.org/x/crypto v0.0.0-20190308221718-c2843e01d9a2/go.mod h1:djNgcEr1/C05ACkg1iLfiJU5Ep61QUkGW8qpdssI0+w=
 golang.org/x/crypto v0.0.0-20191011191535-87dc89f01550/go.mod h1:yigFU9vqHzYiE8UmvKecakEJjdnWj3jj499lnFckfCI=
 golang.org/x/crypto v0.0.0-20200403201458-baeed622b8d8 h1:fpnn/HnJONpIu6hkXi1u/7rR0NzilgWr4T0JmWkEitk=
diff --git a/linebuffer/linebuffer_test.go b/linebuffer/linebuffer_test.go
index 47bf953e..99a4a2cf 100644
--- a/linebuffer/linebuffer_test.go
+++ b/linebuffer/linebuffer_test.go
@@ -5,14 +5,10 @@ import (
 	"testing"
 
 	"github.com/stretchr/testify/assert"
-	"github.com/stretchr/testify/require"
-	"github.com/vektra/neko"
 )
 
 func TestLineBuffer(t *testing.T) {
-	n := neko.Start(t)
-
-	n.It("appends lines to the buffer", func() {
+	t.Run("appends lines to the buffer", func(t *testing.T) {
 		var lb LineBuffer
 
 		lb.Append("hello")
@@ -20,12 +16,12 @@ func TestLineBuffer(t *testing.T) {
 		var buf bytes.Buffer
 
 		n, err := lb.WriteTo(&buf)
-		require.NoError(t, err)
+		assert.NoError(t, err)
 
 		assert.Equal(t, int64(5), n)
 	})
 
-	n.It("wraps around automatically", func() {
+	t.Run("wraps around automatically", func(t *testing.T) {
 		var lb LineBuffer
 
 		lb.Size = 3
@@ -49,7 +45,7 @@ func TestLineBuffer(t *testing.T) {
 		assert.Equal(t, "hello4", lines[2])
 	})
 
-	n.It("wraps around automatically multiple times", func() {
+	t.Run("wraps around automatically multiple times", func(t *testing.T) {
 		var lb LineBuffer
 
 		lb.Size = 3
@@ -76,5 +72,4 @@ func TestLineBuffer(t *testing.T) {
 		assert.Equal(t, "hello7", lines[2])
 	})
 
-	n.Meow()
 }