C program to copy log file frm database

This is a discussion on C program to copy log file frm database within the C Programming forums, part of the General Programming Boards category; Hi folkz, Need help in writing a C program..The scenario is as follows: We need to copy a log file ...

  1. #1
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    C program to copy log file frm database

    Hi folkz,

    Need help in writing a C program..The scenario is as follows:

    We need to copy a log file frm the database to a txt file and the txt file should automatically get updated whenever the log file is modified... Also there shld be a facility to filter data frm the txt file based on a condition...

    Cud anyone help me out with diz..

    Thnx in advance.

    Nirmala.

  2. #2
    Crazy Fool Perspective's Avatar
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    Depending on how your DB writes it's log file, you can do both of those things with a couple of simple linux commands

    1. tail -f db.log > copy.txt
    2. grep "regex condition" copy.txt

  3. #3
    C 1337 Meshal's Avatar
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    it`s easy to take the file from the DB and copy it to a text file ,
    but the big problem how it will be updated automatically ?!!!

  4. #4
    Crazy Fool Perspective's Avatar
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    >but the big problem how it will be updated automatically ?!!!

    tail -f will follow the log, as things are written to it tail will send the changes, through the redirect, to the copy.

  5. #5
    C 1337 Meshal's Avatar
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    tail is a unix command ,,

    i want to do it in C not in Linux Command ,

  6. #6
    C 1337 Meshal's Avatar
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    is my question hard to answer ??!!

  7. #7
    Fear the Reaper...
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    First off, don't bump up your threads.

    Second off, did you ever just think of taking Perspective's answer and just doing system() with those (that is, if you're using linux) ?

    It's system dependant, I know, but I figure you won't really ber ditributing your program, now will you ?
    Teacher: "You connect with Internet Explorer, but what is your browser? You know, Yahoo, Webcrawler...?" It's great to see the educational system moving in the right direction

  8. #8
    and the hat of wrongness Salem's Avatar
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    > i want to do it in C not in Linux Command
    So think about what tail needs to do (or find the source code.

    My guess is something like
    Code:
    while ( 1 ) {
      while ( fgets( buff, sizeof buff, fp ) != NULL ) {
      }
      // got to EOF, now for magic
      clearerr( fp );
      sleep( 1 );
    }
    If you dance barefoot on the broken glass of undefined behaviour, you've got to expect the occasional cut.
    If at first you don't succeed, try writing your phone number on the exam paper.
    I support http://www.ukip.org/ as the first necessary step to a free Europe.

  9. #9
    C 1337 Meshal's Avatar
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    Salem , yes this how it`s done but !
    you have to let the program work in the Background .. ^_^
    with & symbol in Unix machine .

    gcc p.c
    will produce
    a.out
    to make it work in background
    Code:
    &a.out

  10. #10
    C 1337 Meshal's Avatar
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    is there a way guys to make the program work in the background without using & symbol ?!!

  11. #11
    Crazy Fool Perspective's Avatar
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    Whether or not a program runs in the background is up to the user/program that starts it. Why not wrap your program in a script.

    echo "./a.out &" > run.sh
    chmod ug+x run.sh

    The run your script instead of the app directly.

  12. #12
    and the hat of wrongness Salem's Avatar
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    > is there a way guys to make the program work in the background without using & symbol
    Yes.
    If you dance barefoot on the broken glass of undefined behaviour, you've got to expect the occasional cut.
    If at first you don't succeed, try writing your phone number on the exam paper.
    I support http://www.ukip.org/ as the first necessary step to a free Europe.

  13. #13
    Just kidding.... fnoyan's Avatar
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    Quote Originally Posted by Meshal
    is there a way guys to make the program work in the background without using & symbol ?!!
    fork()-execve().

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    Copying works perfectly fine but updation is still a big question mark !! How do i go abt it !! And also incase i want to select records frm the text file based on a condition, how do i do it in C ???

  15. #15
    and the hat of wrongness Salem's Avatar
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    Any better for you?

    Code:
    if ( fork() == 0 ) {
      // Yay, we detached ourselves
      while ( 1 ) {
        while ( fgets( buff, sizeof buff, fp ) != NULL ) {
          // do stuff with the line
        }
        // got to EOF, now for magic
        clearerr( fp );
        sleep( 1 );
      }
    } else {
      // this is the parent, which can now just exit
    }
    If you dance barefoot on the broken glass of undefined behaviour, you've got to expect the occasional cut.
    If at first you don't succeed, try writing your phone number on the exam paper.
    I support http://www.ukip.org/ as the first necessary step to a free Europe.

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