title: How many search strings can fgrep handle?
body: <p>I have a text file (about 1.5 gigabytes) that I want to search for occurrences of specific titles.  There are about 10 million titles in my list.</p>
  
  <p>Obviously, not every title in the list will exist in the text file.  That's okay.  I just need to know which titles exist in the text.</p>
  
  <p>Now, if it was just a couple hundred titles, I'd use <code>fgrep</code> and tell it to read the search strings from a file (i.e. <code>fgrep -f patternlist.txt bigtextfile.txt</code>).</p>
  
  <p>But will <code>fgrep</code> choke on that much data?</p>
  
  <p>It's a little bit of work to turn my titles list and the text file into a form that I could use with <code>fgrep</code>, so I'd like some idea of whether this is likely to work before I go to that effort.</p>
  
  <p>Another option would be to split the titles list into multiple files and run <code>fgrep</code> once for each sub-list.  That's not crazy, provided that <code>fgrep</code> can handle a reasonably large number of search strings.  If it can handle 1 million, it's a no-brainer.  If it can't handle 100,000 (requiring over 100 individual runs), then it's a less attractive option.</p>
  
  <p>So, anybody have experience using <code>fgrep</code> to search for a very large number of strings?  If not, is there some other program available?  I could write my own given a day or two, but if I can avoid the work . . .</p>