use -ww option getting pid from ps with pty lib (because pty's terminal output width is narrow)

ssh.rb

#!/usr/bin/env ruby
# conding: utf-8

#
# this script shows pid which contains 'some_process'
#
require 'pty'
require 'expect'

cmd = 'ssh username@somehost'
PTY.spawn(cmd) do |reader, writer|
  reader.expect(/Password:/)
  writer.puts('password')

  reader.expect(/\]%/)
  writer.puts('ps auxww')

  ps_lines = reader.expect(/\]%/).first.split("\r\n")
  ps_lines = ps_lines[2..ps_lines.size-2]
  #puts ps_lines.inspect

  val = ps_lines.select {|l| l =~ /some_process/ }
  puts val.first.split(' ')[1]
end