diff --git a/packages/scripts/src/Subprocess.test.ts b/packages/scripts/src/Subprocess.test.ts
new file mode 100644
index 0000000..64d279e
--- /dev/null
+++ b/packages/scripts/src/Subprocess.test.ts
@@ -0,0 +1,41 @@
+import {StdioOptions} from './Subprocess'
+import {Subprocess} from './Subprocess'
+
+describe('Subprocess', () => {
+
+  describe('constructor', () => {
+    it('sets stdio to inherit when log true', () => {
+      const p = new Subprocess('test', [], {})
+      expect(p.stdio).toEqual('pipe')
+    })
+    it('sets stdio to ignore when log false', () => {
+      const p = new Subprocess('test', [], {}, StdioOptions.IGNORE)
+      expect(p.stdio).toEqual('ignore')
+    })
+  })
+
+  describe('run', () => {
+
+    // it('rejects on error', async () => {
+    //   const error = await getError(
+    //     new Subprocess('exit 1', environment, StdioOptions.IGNORE).run())
+    //   expect(error.message).toMatch(/exited with code 1/)
+    // })
+
+    // it('logs errors', async () => {
+    //   await getError(
+    //     new Subprocess(
+    //       'invalid-non-existing-command',
+    //       environment, StdioOptions.PIPE,
+    //     )
+    //     .run(),
+    //   )
+    // })
+
+    it('resolves on successful invocation', async () => {
+      await new Subprocess('ls', [], {}, StdioOptions.IGNORE).run()
+    })
+
+  })
+
+})
diff --git a/packages/scripts/src/Subprocess.ts b/packages/scripts/src/Subprocess.ts
new file mode 100644
index 0000000..16e083a
--- /dev/null
+++ b/packages/scripts/src/Subprocess.ts
@@ -0,0 +1,42 @@
+import {spawn} from 'child_process'
+
+export enum StdioOptions {
+  PIPE = 'pipe',
+  INHERIT = 'inherit',
+  IGNORE = 'ignore',
+}
+
+export class Subprocess {
+
+  constructor(
+    public readonly command: string,
+    public readonly args: readonly string[],
+    public readonly environment: Record<string, string | undefined>,
+    public readonly stdio: StdioOptions = StdioOptions.PIPE,
+  ) {}
+
+  async run() {
+    return new Promise((resolve, reject) => {
+      process.stderr.write(`> ${this.command} ${this.args.join(' ')}\n`)
+      const subprocess = spawn(this.command, this.args, {
+        shell: false,
+        stdio: this.stdio,
+        env: this.environment,
+      })
+
+      if (this.stdio === StdioOptions.PIPE) {
+        subprocess.stdout.on('data', data => process.stdout.write(data))
+        subprocess.stderr.on('data', data => process.stderr.write(data))
+      }
+
+      subprocess.on('close', code => {
+        if (code === 0) {
+          resolve()
+        } else {
+          reject(new Error(`"${this.command}" exited with code ${code}`))
+        }
+      })
+      subprocess.on('error', reject)
+    })
+  }
+}
diff --git a/packages/scripts/src/commands/build.ts b/packages/scripts/src/commands/build.ts
index 614d4d6..61a8628 100644
--- a/packages/scripts/src/commands/build.ts
+++ b/packages/scripts/src/commands/build.ts
@@ -1,8 +1,5 @@
-import * as childProcess from 'child_process'
+import {run} from '../run'
 
 export async function build(path: string) {
-  // TODO fix this
-  await childProcess.spawn('npx', ['ttsc', '--build', path], {
-    stdio: 'inherit',
-  })
+  await run('ttsc', ['--build', path])
 }
diff --git a/packages/scripts/src/commands/index.ts b/packages/scripts/src/commands/index.ts
index 6501a0c..ac960ec 100644
--- a/packages/scripts/src/commands/index.ts
+++ b/packages/scripts/src/commands/index.ts
@@ -1,2 +1,3 @@
 export * from './help'
 export * from './build'
+export * from './watch'
diff --git a/packages/scripts/src/commands/watch.ts b/packages/scripts/src/commands/watch.ts
new file mode 100644
index 0000000..10d2f31
--- /dev/null
+++ b/packages/scripts/src/commands/watch.ts
@@ -0,0 +1,5 @@
+import {run} from '../run'
+
+export async function watch(path: string) {
+  await run('ttsc', ['--build', '--watch', '--preserveWatchOutput',  path])
+}
diff --git a/packages/scripts/src/index.ts b/packages/scripts/src/index.ts
index fe82d88..4046665 100644
--- a/packages/scripts/src/index.ts
+++ b/packages/scripts/src/index.ts
@@ -5,7 +5,10 @@ import {TCommand} from './TCommand'
 async function run(...argv: string[]) {
   const commandName = argv[0] || 'help'
   if (!(commandName in commands)) {
-    throw new Error('Command not found:' + commandName)
+    const c = Object.keys(commands).filter(cmd => !cmd.startsWith('_'))
+    console.log(
+      `Available commands:\n\n${c.join('\n')}`)
+    return
   }
   const command = (commands as any)[commandName] as TCommand
   await command(...argv.slice(1))
@@ -13,4 +16,8 @@ async function run(...argv: string[]) {
 
 if (typeof require !== 'undefined' && require.main === module) {
   run(...process.argv.slice(2))
+  .catch(err => {
+    console.log('> ' + err.message)
+    process.exit(1)
+  })
 }
diff --git a/packages/scripts/src/modules.test.ts b/packages/scripts/src/modules.test.ts
new file mode 100644
index 0000000..05cd18f
--- /dev/null
+++ b/packages/scripts/src/modules.test.ts
@@ -0,0 +1,48 @@
+import {getPathVariable, getPathSeparator, findNodeModules} from './modules'
+import {resolve} from 'path'
+import {platform} from 'os'
+
+describe('modules', () => {
+
+  describe('getPathSeparator', () => {
+    it('returns ";" when win32', () => {
+      expect(getPathSeparator('win32')).toEqual(';')
+    })
+    it('returns ":" otherwise', () => {
+      expect(getPathSeparator('linux')).toEqual(':')
+      expect(getPathSeparator('darwin')).toEqual(':')
+      expect(getPathSeparator('mac')).toEqual(':')
+    })
+  })
+
+  describe('findNodeModules', () => {
+    it('should find node_modules/.bin dirs in parent path(s)', () => {
+      const dirs = findNodeModules()
+      expect(dirs.length).toBeGreaterThanOrEqual(1)
+    })
+    it('should not fail when path does not exist', () => {
+      const dirs = findNodeModules('/non/existing/path/bla/123')
+      expect(dirs).toEqual([])
+    })
+  })
+
+  describe('addToPath', () => {
+    it('does nothing when pathsToAdd is empty', () => {
+      const paths = getPathVariable([])
+      expect(paths).toEqual(process.env.PATH)
+    })
+    it('adds paths to path variable', () => {
+      const separator = getPathSeparator(platform())
+      const paths = getPathVariable(['/a', '/b'], '/c')
+      expect(paths).toEqual(`/a${separator}/b${separator}/c`)
+    })
+    it('adds node modules paths to path variable by default', () => {
+      const paths = findNodeModules()
+      const separator = getPathSeparator(platform())
+      expect(paths.length).toBeGreaterThanOrEqual(1)
+      expect(getPathVariable())
+      .toEqual(`${paths.join(separator)}${separator}${process.env.PATH}`)
+    })
+  })
+
+})
diff --git a/packages/scripts/src/modules.ts b/packages/scripts/src/modules.ts
new file mode 100644
index 0000000..fe47d11
--- /dev/null
+++ b/packages/scripts/src/modules.ts
@@ -0,0 +1,36 @@
+import * as fs from 'fs'
+import * as path from 'path'
+import {platform} from 'os'
+
+export function getPathSeparator(platformValue: string) {
+  return platformValue === 'win32' ? ';' : ':'
+}
+
+export function findNodeModules(dir: string = process.cwd()): string[] {
+  let lastPath = ''
+  const paths = []
+  dir = path.resolve(dir)
+  while (dir !== lastPath) {
+    const nodeModulesDir = path.join(dir, 'node_modules', '.bin')
+    if (
+      fs.existsSync(nodeModulesDir)
+      && fs.statSync(nodeModulesDir).isDirectory()
+    ) {
+      paths.push(nodeModulesDir)
+    }
+    lastPath = dir
+    dir = path.resolve(dir, '..')
+  }
+  return paths
+}
+
+export function getPathVariable(
+  pathsToAdd: string[] = findNodeModules(),
+  currentPath = process.env.PATH,
+) {
+  if (!pathsToAdd.length) {
+    return currentPath
+  }
+  const separator = getPathSeparator(platform())
+  return `${pathsToAdd.join(separator)}${separator}${currentPath}`
+}
diff --git a/packages/scripts/src/run.ts b/packages/scripts/src/run.ts
new file mode 100644
index 0000000..67fbd00
--- /dev/null
+++ b/packages/scripts/src/run.ts
@@ -0,0 +1,10 @@
+import {Subprocess} from './Subprocess'
+import {getPathVariable} from './modules'
+
+export async function run(command: string, args: string[]) {
+  return new Subprocess(command, args, {
+    ...process.env,
+    PATH: getPathVariable(),
+  })
+  .run()
+}