title: Remove characters before and including _ in python 2.7
body: <p>The following code returns into a nice readable output.</p>
  
  <pre><code>def add_line_remove_special(ta_from,endstatus,*args,**kwargs):
      try:
          ta_to = ta_from.copyta(status=endstatus)
          infile = botslib.opendata(ta_from.filename,'r')
          tofile = botslib.opendata(str(ta_to.idta),'wb')
          start = infile.readline()
          import textwrap
          lines= "\r\n".join(textwrap.wrap(start, 640))
          tofile.write(lines)
          infile.close()
          tofile.close()
  </code></pre>
  
  <p>This is the output, now I would like to remove all the characters until and including the <code>_</code></p>
  
  <pre><code>Ichg_UNBUNOA3                                   14                2090100000015                      14                1304221445000001
  MSG_BGM380                                         610809                             9  NA
  MSG_DTM13720130422                           102
  Grp1_RFFON test EDI
  Grp2_NADBY 2090100000015                         9
  Grp2_NADIV 2090100000015                         9
  Grp2_NADDP 2090100000015                         9
  Grp7_CUX2  EUR4
  Grp8_PAT22                                                                                              5  3  D   30
  Grp25_LIN1        02090100000022                     EN
  Grp25_QTY47               5
  Grp25_QTY12               5
  Grp26_MOA203             15.00
  Grp28_PRIINV        3000.00           1000PCE
  Grp33_TAX7  VAT                                                                                 21.00                              S
  Grp25_LIN2        02090100000039                     EN
  Grp25_QTY47              10
  Grp25_QTY12              10
  Grp26_MOA203            350.00
  Grp28_PRIINV       35000.00           1000PCE
  Grp33_TAX7  VAT                                                                                 21.00                              S
  </code></pre>
  
  <p>How can I do this?</p>