[SOLVED] The technical difference between df and du

Wim Sturkenboom · 09-13-2011, 01:14 AM

The basic question is:
what does du 'look at' and what does df 'look at' that explains the difference in results.

Background:
If one deletes a file that is in use by an application, du will no longer 'see' it and immediately reflects the change but df will only reflect the change once the application, that has the file open, closes.

macemoneta · 09-13-2011, 01:49 AM

The 'df' command reports what the filesystem says is its space utilization - internal accounting done as blocks are allocated and freed. The 'du' command adds up the space used by the files that you specified. You'll notice that df always runs very fast for that reason, while du can take a long time if it needs to total many files.