On Wed, Mar 18, 2009 at 07:30:01PM -0400, Kris Maglione wrote: > On Thu, Mar 19, 2009 at 12:16:10AM +0100, Martin Kraus wrote: >> Basicaly I'd expect this not to work, since wmiir is reading and at the same >> time overwriting the data. It had worked as far as I've tried. Is it because >> wmiir first reads all the data and then outputs it so that the other wmiir >> write will just overwrite alread read data, or have I been lucky and reading >> from the file was just always quicker then writing to it? >> >> Simply put, can I safely use the above syntax or should I read it into a >> variable and then overwrite it? > > Well, you can safely use it as long as you have less than about 8K of > colrules. It actually works because wmii truncates those files to the > last byte written on every write, but wmiir doesn't write anything to the > filesystem until it recieves something from stdin. Since it won't recieve > anything until the first wmiir finishes its read, you're fine as long as > the first read returns the whole file (which it will if it's under 8K). > > So, that was more than you asked for. How about this: I'll just add a -a > flag to 'wmiir write'.
Thanks. I thought as much. I realised I can actually have a look at the source since it is open:) Even with my rusty C knowledge it is quite obvious once I've started using a bit of that thing of mine called brain. Sometimes I think I'm getting too old. thanks for the complete explanation. mk
