OSError: [Errno 2] No such file or directory

bench start:

18:19:48 system | worker_short.1 started (pid=2012)
18:19:53 socketio.1 |
18:19:53 socketio.1 | /home/frappe/frappe-bench/node_modules/socket.io/node_modules/socket.io-client/node_modules/engine.io-client/node_modules/ws/index.js:9
18:19:53 socketio.1 | const WebSocket = require(’./lib/WebSocket’);
18:19:54 socketio.1 | ^^^^^
18:19:54 socketio.1 | SyntaxError: Use of const in strict mode.
18:19:54 socketio.1 | at Module._compile (module.js:439:25)
18:19:54 socketio.1 | at Object.Module._extensions…js (module.js:474:10)
18:19:54 socketio.1 | at Module.load (module.js:356:32)
18:19:54 socketio.1 | at Function.Module._load (module.js:312:12)
18:19:54 socketio.1 | at Module.require (module.js:364:17)
18:19:54 socketio.1 | at require (module.js:380:17)
18:19:54 socketio.1 | at Server.init (/home/frappe/frappe-bench/node_modules/socket.io/node_modules/engine.io/lib/server.js:119:16)
18:19:54 socketio.1 | at new Server (/home/frappe/frappe-bench/node_modules/socket.io/node_modules/engine.io/lib/server.js:65:8)
18:19:54 socketio.1 | at Function.attach (/home/frappe/frappe-bench/node_modules/socket.io/node_modules/engine.io/lib/engine.io.js:123:16)
18:19:54 socketio.1 | at /home/frappe/frappe-bench/node_modules/socket.io/lib/index.js:258:23
18:19:54 socketio.1 | at Encoder.encode (/home/frappe/frappe-bench/node_modules/socket.io/node_modules/socket.io-parser/index.js:138:5)
18:19:54 system | socketio.1 stopped (rc=8)

bench update:

Updating DocTypes for frappe : [========================================]
Updating DocTypes for erpnext : [========================================]
Syncing help database…
Traceback (most recent call last):
File “/usr/lib/python2.7/runpy.py”, line 162, in _run_module_as_main
main”, fname, loader, pkg_name)
File “/usr/lib/python2.7/runpy.py”, line 72, in _run_code
exec code in run_globals
File “/home/frappe/frappe-bench/apps/frappe/frappe/utils/bench_helper.py”, line 79, in
main()
File “/home/frappe/frappe-bench/apps/frappe/frappe/utils/bench_helper.py”, line 16, in main
click.Group(commands=commands)(prog_name=‘bench’)
File “/home/frappe/frappe-bench/env/local/lib/python2.7/site-packages/click/core.py”, line 722, in call
return self.main(*args, **kwargs)
File “/home/frappe/frappe-bench/env/local/lib/python2.7/site-packages/click/core.py”, line 697, in main
rv = self.invoke(ctx)
File “/home/frappe/frappe-bench/env/local/lib/python2.7/site-packages/click/core.py”, line 1066, in invoke
return _process_result(sub_ctx.command.invoke(sub_ctx))
File “/home/frappe/frappe-bench/env/local/lib/python2.7/site-packages/click/core.py”, line 1066, in invoke
return _process_result(sub_ctx.command.invoke(sub_ctx))
File “/home/frappe/frappe-bench/env/local/lib/python2.7/site-packages/click/core.py”, line 895, in invoke
return ctx.invoke(self.callback, **ctx.params)
File “/home/frappe/frappe-bench/env/local/lib/python2.7/site-packages/click/core.py”, line 535, in invoke
return callback(*args, **kwargs)
File “/home/frappe/frappe-bench/apps/frappe/frappe/commands/utils.py”, line 16, in build
frappe.build.bundle(False, make_copy=make_copy, verbose=verbose)
File “/home/frappe/frappe-bench/apps/frappe/frappe/build.py”, line 37, in bundle
subprocess.call(command.split(’ '))
File “/usr/lib/python2.7/subprocess.py”, line 522, in call
return Popen(*popenargs, **kwargs).wait()
File “/usr/lib/python2.7/subprocess.py”, line 710, in init
errread, errwrite)
File “/usr/lib/python2.7/subprocess.py”, line 1327, in _execute_child
raise child_exception
OSError: [Errno 2] No such file or directory