Hi one and all,

I'm working on a Bash script that is designed to calculate how much IP traffic has passed through a port to determine traffic volume over a given amount of time.

I've currently been able to use the netstat -s command coupled with grep to write to a file the total packets received and I can't figure out how to use these numbers in a script to perform mathematical functions between them.

These are the numbers I've obtained:
So with these numbers I want to use them in a script that subtracts the first reading from the second and the third reading from the fourth - bearing in mind that these numbers could be any size, any length everytime I run the netstat -s cmd.

Will I have to make each line unique so i can grep out just the actual numbers? (How would I do that with physically modifying the txt file).

Any pointers and/or suggestions welcome.

Try this on when catting your tmpfile. This would only work if there is spaces before the numbers in your tmpfile, as it looks like there are.

try this...

Great stuff guys, thank you for that.

I hate to tap your brains again but here goes:

Now that I have just the numbers displayed within the file is there anyway I can call upon the numbers in a script so I can perform the workings out on them?

What i'm trying to achieve to get is the difference between the readings:

1st reading - 2nd reading
3rd reading - 4th reading

but I'm not sure on how to get these random numbers into a script.

I have a few thoughts:

Should I turn them into variables within the file and then use the variables in my script

ie edit the text file from my script and turn each number into a variable, so it'll look something like this:

then call upon them in my script to do the maths - how would I assign the varibles within my script and how do I get these variables into my script?

OR:

is there a way to select line 1 from the file and make it a variable in my script then line 2 etc (remembering that these numbers are random so "greping" will not work).

Regards

If you get the numbers by themselves in a file, you can do the below to set them to variables.

Thank you.

That's perfect for my script. I've been bashing my head for a week over this! I can get on with other things now.

Thanks for all replies

Cheers

Hi, here's some ideas applied to Your data... assuming (including any number of space):
The first example is a method I use a lot in different versions, basically presenting the diff in a value from it's previous value. Good for analysing data from log files for example. And since there is always a beginning for everything, I chose in this case, 0:

And if You want only diff from every other line (if this is what You meant):

Try changing [ $((cnt % 2)) -eq 1 ] for a different result. It's a construct to return true if You are on an even line. Well, er... yes, it's uneven with regard to cnt, but we usually we start counting from 0, so, oh, whatever... fiddle about with it! Change -eq to 0 for a different, "shifted", result.
The x y z is just to consume values from tmpIP file, otherwise the whole line would be considered one variable.
The read is good for ignoring whitespace, as many other clu's are.

Well, just my 2 öre!

/Lakris

PS Oh, almost forgot... maybe You could consider piping Your data collecting directly through the while loop, and not using intermediate files. Just a thought.