Can you use some sort of 'tail' command to get the last lines? DA
On 7/16/05, Wiggins d'Anconia <[EMAIL PROTECTED]> wrote: > Octavian Rasnita wrote: > > Hi, > > > > I need to create a program which reads a file from the LAN, and that file is > > continuously updated (kind of log). > > The file increases continuously, and it can become very big. > > > > On every read, I need to read just the lines for the current day (which is > > specified in each line) and jump over the lines from the previous days. > > > > The problem is that if I just open() the file and verify each line to see if > > it is a good one, takes very much time, and I need to find a faster > > solution. > > > > Checking each line might take a long time, but I think that verifying each > > line means downloading the whole content of the file on my computer, and > > this will also make the program lose much time. > > > > Do you have any idea what can I do to make the program run faster? > > > > I am thinking to make the program in such a way that after the first run, it > > gets the line number of the first line from the current day, or the number > > of the first bit of the start of that line, then on next times it runs, it > > jumps directly to that line somehow (?), or directly to that bit (using > > seek), but I don't know if in that case the content of the file won't be > > also downloaded to my computer. > > > > Do you have any idea how I can download just a part of a file from the > > network? > > > > If my understanding is correct that would have to be something built > into the protocol of whatever network protocol you are using. Your seek > idea should be correct, and I know for instance modern FTP servers have > the ability to seek to a different part of a file, in which case the FTP > server only provides that remaining portion of the file on a get (this > is how pause/resume downloaders are implemented). And some HTTP servers > have this capability. You should probably check with the protocol docs > to see if it has the capability. Assuming the protocol is advanced > enough then it should respect a seek and not provide the whole file. The > best thing to do in this kind of case is to setup some sort of network > monitoring and then just try it. See if you open a large file, seek to a > location near the end and then see if the network gets slammed or if > only the small sample of file is sent. > > perldoc -f seek > > For more info. > > > Help! > > > > Thank you. > > > > Teddy > > > > Good luck, > > http://danconia.org > > -- > To unsubscribe, e-mail: [EMAIL PROTECTED] > For additional commands, e-mail: [EMAIL PROTECTED] > <http://learn.perl.org/> <http://learn.perl.org/first-response> > > > -- To unsubscribe, e-mail: [EMAIL PROTECTED] For additional commands, e-mail: [EMAIL PROTECTED] <http://learn.perl.org/> <http://learn.perl.org/first-response>
