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.
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
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 ?!!!
>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.
tail is a unix command ,,
i want to do it in C not in Linux Command ,
is my question hard to answer ??!!
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
> 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.
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
is there a way guys to make the program work in the background without using & symbol ?!!
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.
> 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.
fork()-execve().Originally Posted by Meshal
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 ???
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.
