From: Paul Archer <paul@...>
Date: 2009-07-17T11:06:37+09:00
Subject: Re: making sure a file isn't being written/copied before moving

Tomorrow, Gary Wright wrote:

>>> Paul Archer wrote:
>>>> Can someone suggest an easy (or at least reliable)  way to make sure
>>>> that
>>>> any file I'm about to modify isn't being touched by another program?
>>> 
>>> As you said yourself: rely on the atomic semantics of the filesystem.
>>> Rename it to an extension which the other program will not recognise, or
>>> into another directory which the other program won't be looking in.
>>> 
>> 
>> Perhaps you missed it in my original post (or perhaps I simply wasn't 
>> clear), but I may be operating on files that are added arbitrarily. My 
>> concern is that the script starts acting on a file that is still being 
>> copied. Renaming it won't help there.
>
> Just use the renaming semantics in the first program (the one doing the 
> copying) also.  Basically you are using the filename appearance as a 
> synchronization mechanism between the multiple processing steps.
>
> If you can't control the name of the file itself, then control the directory 
> in which it appears.
>

That still leaves me with the same problem: I have to read out of a 
directory. Plus, there isnt' just going to be a script putting files in my 
incoming directory. I'll be doing that myself as I clean up all my old 
files.

Paul