title: Invalid character ' ' in expression
body: <p>top of the day all .please I have checked the other errors that looked alike or wit hthe same error code. they seems not to be the same. I will need your help. hanks all</p>
  
  <pre><code># Create awk program : myflowcalcall.awk
  
  # a general script for computing throughput
  
  BEGIN {
          arguments = 2;
       if (ARGC &lt; arguments || ARGC &gt; arguments || flowtype == 0) {
          printf("error: wrong number of arguments.\nawk: usage – awk -f flowcalc.awk [-v graphgran=value] [-v fidfrom=value] [-v fidto=value] [-v fid=value] -v flowtype=\"type\" -v outdata_file=\"filename\" indata_file\n–%d",ARGC);
          exit;
                                  }
  measure_interval = 0.5;
  bits = 0;
  first_time = graphgran;
      }
  
      {
      if (($1 == "r") &amp;&amp;
      ((fidfrom == 0 &amp;&amp; fidto ==0) || (($8 == fid) &amp;&amp; ($3 == fidfrom) &amp;&amp; ($4 == fidto))) &amp;&amp;
      (flowtype == "all" || flowtype == $5)) {
  if (($2 - first_time) &gt; measure_interval)   {
      first_time = first_time + measure_interval;
      rate = (bits/1000000)/first_time;
      print filename first_time, rate;
                          }
  bits = bits + $6 * 8;
                      }
      }
  END {
  measure_interval = 0.5;
  first_time = first_time + measure_interval;
  rate = (bits/1000000)/first_time;
  print filename first_time, rate;
  }
  </code></pre>
  
  <p>there is an error that </p>
  
  <blockquote>
    <p>awk: myflowcalcall.awk:20:     if (($2 – first_time) > measure_interval) {
    awk: myflowcalcall.awk:20:             ^ invalid char '�' in expression</p>
  </blockquote>
  
  <p>I have tried and checked  the error but to no avail. below is the command I gave to run from the terminal in Ubuntu 12.04LTS</p>
  
  <blockquote>
    <p>awk -f myflowcalcall.awk -v graphgran=0 -v fidfrom=2 -v fidto=3 -v fid=1 -v flowtype=”cbr” -v outdata_file=”nothing” johna4bp.tr > thr1</p>
  </blockquote>
  
  <p>running the </p>
  
  <pre><code>xxd myflowcalcall.awk | grep " e2\|e2 "
  </code></pre>
  
  <p>produced </p>
  
  <pre><code>00000f0: 6177 6b3a 2075 7361 6765 20e2 8093 2061  awk: usage ... a
  0000190: 6174 615f 6669 6c65 5c6e e280 9325 6422  ata_file\n...%d"
  00002c0: 2828 2432 20e2 8093 2066 6972 7374 5f74  (($2 ... first_t
  </code></pre>
  
  <p>may I know the points of error. thanks all</p>