title: Need help on “Regular expression” catch any illegal characters
body: <p>I need to catch any illegal character that invalid in Unix filename such as space , but excluding Japanase, Chinese character, etc (those are valid character in Unix filename) using regular expression. Please advise what should be the right regular expression.</p>
  
  <p>Ex:</p>
  
  <p>Source string: <code>RE  MCS CONS対応依頼（CarePack購入希望 ありたみつのぶ'様）</code></p>
  
  <p>Target String: It should not have any special charactors except valid japanese Chinese characters. </p>
  
  <p>I would like to replace spaces and spacial charactors with _ (Under score).
  So the final string should have only english alpha numeric characters, _ (Under score), valid Japanese and Chinese chars. So that I use this final string as file name to create a file in UNIX.</p>