title: How to restrict Shiny fileInput to text files only?
body: <p>I want to restrict my file browser to displaying only the types of file I specify, e.g. .txt files only. The only relevant snippets of a code I found are like the following:</p>
  
  <pre><code>fileInput("in_file", 
            "Input file:",
            accept=c("txt/csv", "text/comma-separated-values,text/plain", ".csv") 
  </code></pre>
  
  <p>However, this does't filter the files showing in the browser to just .txt and .csv. Any ideas?</p>