title: What does "$1/*" mean in "for file in $1/*"
body: <p>The short bash script below list all files and dirs in given directory and its sub. What does the <code>$1/*</code> mean in the script? Please give me some references about it. Thanks</p>
  
  <pre><code>#!/bin/sh
  
  list_alldir(){
      for file in $1/*
      do
          if [ -d $file ]; then
              echo $file
              list_alldir $file
          else
              echo $file
          fi
      done
  }   
  
  if [ $# -gt 0 ]; then 
      list_alldir "$1"
  else
      list_alldir "."
  fi
  </code></pre>