Installation error on ubuntu 14.04 lts

I am also getting following error when I am running bench setup socketio

/bin/sh: 1: npm: not found
Traceback (most recent call last):
  File "/usr/local/bin/bench", line 9, in 
    load_entry_point('bench', 'console_scripts', 'bench')()
  File "/home/fikru/bench-repo/bench/cli.py", line 40, in cli
    bench_command()
  File "/usr/local/lib/python2.7/dist-packages/click/core.py", line 716, in call
    return self.main(*args, **kwargs)
  File "/usr/local/lib/python2.7/dist-packages/click/core.py", line 696, in main
    rv = self.invoke(ctx)
  File "/usr/local/lib/python2.7/dist-packages/click/core.py", line 1060, in invoke
    return processresult(sub_ctx.command.invoke(sub_ctx))
  File "/usr/local/lib/python2.7/dist-packages/click/core.py", line 889, in invoke
    return ctx.invoke(self.callback, **ctx.params)
  File "/usr/local/lib/python2.7/dist-packages/click/core.py", line 534, in invoke
    return callback(*args, **kwargs)
  File "/home/fikru/bench-repo/bench/commands/make.py", line 19, in init
    verbose=verbose, clone_from=clone_from)
  File "/home/fikru/bench-repo/bench/utils.py", line 64, in init
    setup_socketio(bench_path=path)
  File "/home/fikru/bench-repo/bench/utils.py", line 140, in setup_socketio
    exec_cmd("npm install socket.io redis express superagent cookie", cwd=bench_path)
  File "/home/fikru/bench-repo/bench/utils.py", line 130, in exec_cmd
    raise CommandFailedError(cmd)
bench.utils.CommandFailedError: npm install socket.io redis express superagent cookie

im getting error while installting,
im very new of ubuntu and erpnext
using ubuntu 14.04 VNC on VPS

fresh rebuild
used these commands
sudo apt-get install python-minimal


wget https://raw.githubusercontent.com/frappe/bench/master/playbooks/install.py
sudo python install.py --production --user frappe

I have spent two days for install ERPNext (latest version) on Ubuntu 14 / 16 64bit many times but no success ( sudo python install.py --production --user frappe ) - I installed many times, no error occurred until the present :grimacing:

You don’t say what problem you are having.

As the code evolves installs can be a recurring problem, for example this episode
*SOLVED* Install.py now FAILS on Unbuntu 14.04, Debian 8, Centos 7. What happened? (also same on Ubuntu 16.04) *SOLVED*

This resource may help give you more perspective erpnext_admin_guide | ERPNext Administrators Guide