st: timestamps, GNU/make-style Stata program

[James Muller <james.muller@internode.on.net>]

Hello List,

I'm wishing to do something (described below), but am unsure of exactly 
how to implement it (question at bottom). Read on.

I'm wishing to implement something like GNU/make in a project I'm 
working on. That is, something that will compare file timestamps to see 
whether a dataset, for instance, needs to be rebuilt from a set of 
scripts. If the timestamp on the do files is more recent than that of 
the dataset it generates then the dataset should be regenerated. This is 
a very efficient way of resolving dependencies and such.

I've been looking hard and can't find anything within Stata that returns 
the timestamp of a file. The only way I can find to do this on a .dta 
file is by reading the file contents itself (there is a text-formatted 
timestamp in the header of the file). I can't find a way to check the 
timestamp of any other type of file.

There are two alternatives I can see:
1. Call the operating system to return the code, try to somehow capture 
the output.
2. Use the checksum function along with some other files that contain 
the last known checksum.

Assuming there isn't anything within Stata to do this, the operating 
system method is best, but I'm not sure how to capture the OS output - 
do something with environment variables, perhaps.

So here's what I ask:
1. Has anybody tried to do something similar before? If so, what was 
your experience?
2. Is there an internal Stata method to read the timestamp of a file? 
Version 8.2 preferable to version 9.0.
3. If not, does anybody have any experience with capturing operating 
system output to Stata?
4. Any comments, etc, at all?

Cheers in advance

James

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