Shanika Amarasoma

Consider an Apache access log file like below,

192.168.250.40 - - [11/Oct/2013:11:59:59 +0700] "POST /process.php HTTP/1.0" 200 -
192.168.250.10 - - [11/Oct/2013:12:00:00 +0700] "POST /process.php HTTP/1.0" 200 -
192.168.250.10 - - [11/Oct/2013:12:00:00 +0700] "POST /process.php HTTP/1.0" 200 -
192.168.250.10 - - [11/Oct/2013:12:00:00 +0700] "POST /process.php HTTP/1.0" 200 -
192.168.250.10 - - [11/Oct/2013:11:59:59 +0700] "POST /process.php HTTP/1.0" 200 -
192.168.250.10 - - [11/Oct/2013:12:00:00 +0700] "POST /process.php HTTP/1.0" 200 -
192.168.250.10 - - [11/Oct/2013:11:59:59 +0700] "POST /process.php HTTP/1.0" 200 -
192.168.250.40 - - [11/Oct/2013:12:00:00 +0700] "POST /process.php HTTP/1.0" 200 -
192.168.250.40 - - [11/Oct/2013:12:00:00 +0700] "POST /process.php HTTP/1.0" 200 -
192.168.250.10 - - [11/Oct/2013:11:59:59 +0700] "POST /process.php HTTP/1.0" 200 -
192.168.250.10 - - [11/Oct/2013:12:00:00 +0700] "POST /process.php HTTP/1.0" 200 -
192.168.250.40 - - [11/Oct/2013:11:59:59 +0700] "POST /process.php HTTP/1.0" 200 -

If we separate one line by the space fourth portion has the time component. We can easily do it by “cut” command.

cut -d" " -f4 access.log | head

Here -d” “ cut the line by space, -f4 print the fourth portion and finally “head” will show only fist 10 lines

[11/Oct/2013:12:00:00
[11/Oct/2013:11:59:59
[11/Oct/2013:11:59:59
[11/Oct/2013:11:59:59
[11/Oct/2013:11:59:59
[11/Oct/2013:11:59:59
[11/Oct/2013:11:59:59
[11/Oct/2013:11:59:59
[11/Oct/2013:11:59:59
[11/Oct/2013:12:00:00

In this result, the time value is in between 14th character and 21st character (-c14-21). So we’ll pipe this result through another “cut“.

cut -d" " -f4 access.log | cut -c14-21 | head

It will give,

12:00:00
11:59:59
11:59:59
11:59:59
11:59:59
11:59:59
11:59:59
11:59:59
11:59:59
12:00:00

Now we have to count this result by grouping the lines. “uniq -c” will do it. But remember to “sort” before counting.

cut -d" " -f4 access.log | cut -c14-21 | sort | uniq -c | head

Now we’ll get a result something like,

     
     42 11:59:59
   1161 12:00:00
    977 12:00:01
    884 12:00:02
    976 12:00:03
   1065 12:00:04
   1017 12:00:05
    936 12:00:06
    926 12:00:07
    981 12:00:08

This means that there were 1161 requests at 12:00:00, 977 at 12:00:01, 884 at 12:00:02 …etc. Now we want to find the maximum value of the first column. So we’ll “sort” the first column (-k 1) again numerically (-n) in revers (-r) order.

cut -d" " -f4 access.log | cut -c14-21 | sort | uniq -c | sort -k 1 -n -r | head

Now we see the final results.

   1253 12:17:12
   1222 12:17:14
   1201 12:32:23
   1174 12:13:00
   1169 12:00:38
   1167 12:56:23
   1161 12:00:00
   1159 12:14:22
   1158 12:14:52
   1156 12:18:37

The maximum requests per second is 1222 and it has happened at 12:17:14.
There may also be some other methods to find this. But, anyway you learned three commands from this post which are very useful for simply analyzing log files.

This example describes how to move a image on web browser using arrow keys.

Up -> Move Forward
Down -> Move Backward
Left -> Rotate Left
Right -> Rotate Right

jQuery and jQuery Rotate libraries are used.

Javascript code is as follows.

var angle=-90;
var maxL = 0;
var maxT = 0;
var move_amt = 5;
function update()
{
	var position = $("#my_image").offset();
	$("#t").text(Math.round(position.top));
	$("#l").text(Math.round(position.left));
	$("#a").text(angle*(-1)%360);
}
function rotate_left()
{
	$("#my_image").rotate(--angle);
	update();
}
function rotate_right()
{
	$("#my_image").rotate(++angle);
    	update();
}
function move_forward()
{
	var position = $("#my_image").offset();
	var new_left=position.left+move_amt*Math.cos(angle*(-1)* Math.PI/180);
	if(new_left < 0)
	{
		new_left=0;
	}
	if(new_left > maxL)
	{
		new_left=maxL;
	}
	var new_top=position.top-move_amt*Math.sin(angle*(-1)* Math.PI/180);
	if(new_top < 0)
	{
		new_top=0;
	}
	if(new_top > maxT)
	{
		new_top=maxT;
	}
	$("#my_image").offset({ left: Math.round(new_left), top: Math.round(new_top)})
	update();
}
function move_backward()
{
	var position = $("#my_image").offset();
	var new_left=position.left-move_amt*Math.cos(angle*(-1)* Math.PI/180);
	if(new_left < 0)
	{
		new_left=0;
	}
	if(new_left > maxL)
	{
		new_left=maxL;
	}
	var new_top=position.top+move_amt*Math.sin(angle*(-1)* Math.PI/180);
	if(new_top < 0)
	{
		new_top=0;
	}
	if(new_top > maxT)
	{
		new_top=maxT;
	}
	$("#my_image").offset({ left: Math.round(new_left), top: Math.round(new_top)})
	update();
}
$(document).ready(function(){
maxL = $('body').width()-64;
maxT = $(window).height()-64;
$("#my_image").offset({ left: Math.round(maxL/2), top: Math.round(maxT/2)})
$("#my_image").rotate(angle);
update();
$("body").keydown(function(e) {
  if(e.which == 37) { // left
    rotate_left();
  }
  else if(e.which == 38) { // up
    move_forward();
  }
  else if(e.which == 39) { // right
    rotate_right();
  }
  else if(e.which == 40) { // right
    move_backward();
  }
});	
});

You can try the demo from Here

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