Shell Programming and Scripting

hi!
i have a 8192 lines file like this ( the time will not change)

12:43:17 -69 -
12:43:17 -66 -
12:43:17 -71 -
12:43:17 -71 -
12:43:17 -70 -
12:43:17 -66 -
12:43:17 -70 -
12:43:17 -66 -
12:43:17 -71 -
12:43:17 -71 -
12:43:17 -67 -
12:43:17 -69 -
12:43:17 -69 -
12:43:17 -66 -
it's too big to threat so i have to an average of the 2nd column every 128 lines?
the final file will contain 64 lines like this
12:43:17 average of the 1st 128lines
12:43:17 average of the 2nd 128lines

thank you

Try something like this:

Code:

awk -F'-' '{ sum += $2 ; if( NR%128 == 0) { print $1, sum/128; sum = 0 } }' filename

thank you!
it works!
but at the end of the lines, i have a 0
in example:
12:43:17 -68 - 0
12:43:17 -66 - 0
12:43:17 -67 - 0
12:43:17 -69 - 0
12:43:17 -66 - 0
12:43:17 -67 - 0
12:43:17 -69 - 0
12:43:17 -67 - 0

and of course, i don't want it..
is there any possibility?
if not, i will do another awk script to delete it
thank you again

The last 0 doesn't affect the code output. Then whats the problem ?

i think i have a problem with my code.

thank you for your help!!

just replace a.txt with your file and assign $line to your number 128 or whatever, then below script should help you.

Code:

#!/usr/bin/perl
$line=8;
open FH,"<a.txt";
while(<FH>){
	my @tmp=split("-",$_);
	$n+=$tmp[1];
	if ( $. % $line == 0){
		print $tmp[0]," : ",$n/$line,"\n";
		$n=0;
	}
	$pre=$tmp[0] unless $pre;
}
print $pre," : ",$n/($. % $line) if $. % $line;