Is there a Windows equivalent to the Unix du command? [duplicate]

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I am troubleshooting performance on a PC with (running Windows 7) whose hard disk is almost full. I am assuming that there is some directory where the user has dumped many large files. On Unix, I would use the 'du' command to determine which directories contributed most to disk usage. How do I accomplish this on Windows? TIA - Frank

Use something like TreeSize Free from JAM Software or WinDirStat which is open source.

There is the sysinternals du command but you may find something more native like getfoldersize easier to use.