What is the difference between `du` and `df` command?


  • stands for Disk Free
  • calculates file size based on the file system meta information
  • if block size is 8kb and file size is only 1kb then file size for du is 8kb
  • is faster but not accurate


  • Disk Usage
  • counts size used on the file system per file recursively (df and du giving different results)
  • does not count open files
  • does not rely on block size: 1kb file size with 8kb block size is still 1kb for du
  • is slow, but more reliable

See this post from Mike Golvach for thorough explanation: Why DU And DF Display Different Values On Linux And Unix