Shell Programming and Scripting

Hi,

I'm posting my question here as I fele that what I am about to try to do must have been done already, and I don't want to re-invent the wheel.

I have recently become responsible for monitoring disk space usage for a large file system.

I would like to geenrate reports that will summise the amount of disk space used by directories at a certain level, grouped into date ranges.

e.g. results

Code:

Last modified : file path          : total
 0 - 1 months : /foo/foo_01/bar_01 : 101 GB
                /foo/foo_01/bar_02 :  98 GB
                /foo/foo_02/bar_03 : 202 GB
                /bar/bar_01/etc    : 203 GB
 1 - 6 months : /foo/foo_01/bar_04 : 405 GB
                /bar/bar_02/etc    : 203 GB
                /bar/bar_03/etc    : 203 GB
6 - 12 months : /bar/bar_03/tmp    :  20 GB
                /bar/bar_01/tmp    :  22 GB
12 months +   : /bar/bar_02/tmp    : 203 GB

I hope that gives some idea of what I am trying to achive. Basically, I want to highlight large areas of the filesystem that can be archived off because they have not been accessed for some time.

If anyone can point me towards any scripts already written that would do this or something I can modify to do it I would appreciate it.

At the moment I am loking at starting from scratch, which I'd enjoy, but will take some time.

I can not install any software - it must be script based.

Thanks for any tips/advice!