Get lines in 5 seconds - Shell Programming and Scripting

Lestat · #1 06-15-2005

Hello everybody, how i can get how many lines are writed in a file in the last 5 seconds?

For ezample i have 'file1' that is filled by a process automatically and i neet to know how many lines with the word 'EXACTO' were filled the last 5 seconds, can somebody help me?

I try with:

Code:

tail -f file1 | grep EXACTO > file2

but it just copy the last files to 'file2' but not in the last 5 seconds, that have sence? please your help.

Lestat

pixelbeat · #2 06-15-2005

tail -f -s5 ?

Just Ice · #3 06-15-2005

try ...

Code:

currcnt=0
oldcnt=0
while true
do
    currcnt=$(wc -l file1 | awk '{print $1}')
    if [ $currcnt -ne $oldcnt ]
    then
        sed "1,${oldcnt}d" file1 | grep "EXACTO" >> file2
        oldcnt=$currcnt
    fi
    sleep 5
done

Lestat · #4 06-15-2005

pixelbeat it still dont work, 'tail -f -s5 file1 works' but not just 5 seconds, it works like 'tail -f file1'

jim mcnamara · #5 06-15-2005

File writes do not always work the way you think they do.

Unless the process writing the file calls fflush() for every line or is using aio calls, the kernel accumulates file data in memory for a while, then writes a bunch of stuff all at once to the file. The bunch of stuff it decides to write may end somewhere in the middle of a line.

What this means is that you could wait for 20 seconds, while nothing is written to the file. Then during the 21st second, 8192 bytes of data is written to the file.

Just Ice · #6 06-15-2005

but that doesn't preclude the op from checking every 5 seconds if he wished ...

Lestat · #7 06-15-2005

At first time i try to get whe num of lines actual, then the num of lines in 5 seconds then the difference between they, but in 'file1' i have thousand of lines and a 'wc -l file1' take to much time...

For Jim Mcnamara:
The file1 is filled in real time, so i dont have problem like that (i think)

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