dear all,
I have the following situation that I don't have a good solution:
One process periodically will append its output to a file (which is
not under my control), I want to write a ruby problem to detect and
report only the *new* stuff that went into the output file ... Besides
the brute force way such as opening the file and counting the lines
etc, is there a better solution to it?
Thanks for help
Oliver
You can use File.stat('filename').size to get the number of bytes in
the file or .mtime to find the last modification time. If the bytes
and/or time changes you can then open the file and grab the new lines.
Gary Wright
On Nov 28, 2007, at 3:05 PM, Oliver wrote:
One process periodically will append its output to a file (which is
not under my control), I want to write a ruby problem to detect and
report only the *new* stuff that went into the output file ... Besides
the brute force way such as opening the file and counting the lines
etc, is there a better solution to it?
You can do something like this:
f = File.new('logfile.log')
while true
while(line = f.gets)
puts line
end
sleep 5
end
On Nov 28, 2007 3:21 PM, Gary Wright <gwtmp01@mac.com> wrote:
On Nov 28, 2007, at 3:05 PM, Oliver wrote:
> One process periodically will append its output to a file (which is
> not under my control), I want to write a ruby problem to detect and
> report only the *new* stuff that went into the output file ... Besides
> the brute force way such as opening the file and counting the lines
> etc, is there a better solution to it?You can use File.stat('filename').size to get the number of bytes in
the file or .mtime to find the last modification time. If the bytes
and/or time changes you can then open the file and grab the new lines.Gary Wright
Thanks to both of you for the solution.
The double while loop seems a bit more concise, but it depends on
File#gets method handles the changing file content correctly. I will
give it a spin.
Best,
Oliver
On Nov 28, 3:33 pm, Christian von Kleist <cvonkle...@gmail.com> wrote:
You can do something like this:
f = File.new('logfile.log')
while true
while(line = f.gets)
puts line
end
sleep 5
endOn Nov 28, 2007 3:21 PM, Gary Wright <gwtm...@mac.com> wrote:
> On Nov 28, 2007, at 3:05 PM, Oliver wrote:
> > One process periodically will append its output to a file (which is
> > not under my control), I want to write a ruby problem to detect and
> > report only the *new* stuff that went into the output file ... Besides
> > the brute force way such as opening the file and counting the lines
> > etc, is there a better solution to it?> You can use File.stat('filename').size to get the number of bytes in
> the file or .mtime to find the last modification time. If the bytes
> and/or time changes you can then open the file and grab the new lines.> Gary Wright
You're welcome! That approach has worked for me many times in the
past in many languages, including Ruby. Give it a run!
On Nov 28, 2007 4:20 PM, Oliver <fwang2@gmail.com> wrote:
Thanks to both of you for the solution.
The double while loop seems a bit more concise, but it depends on
File#gets method handles the changing file content correctly. I will
give it a spin.Best,
Oliver
On Nov 28, 3:33 pm, Christian von Kleist <cvonkle...@gmail.com> wrote:
> You can do something like this:
>
> f = File.new('logfile.log')
>
> while true
> while(line = f.gets)
> puts line
> end
> sleep 5
> end
>> On Nov 28, 2007 3:21 PM, Gary Wright <gwtm...@mac.com> wrote:
>
>
>
> > On Nov 28, 2007, at 3:05 PM, Oliver wrote:
> > > One process periodically will append its output to a file (which is
> > > not under my control), I want to write a ruby problem to detect and
> > > report only the *new* stuff that went into the output file ... Besides
> > > the brute force way such as opening the file and counting the lines
> > > etc, is there a better solution to it?
>
> > You can use File.stat('filename').size to get the number of bytes in
> > the file or .mtime to find the last modification time. If the bytes
> > and/or time changes you can then open the file and grab the new lines.
>
> > Gary Wright