Linux / Unix logtop: Realtime Log Line Rate Analyser


ow can I analyze line rate taking log file as input on a Linux system? How do I find the IP flooding my Apache/Nginx/Lighttpd web-server on a Debian or Ubuntu Linux?


You need to use a tool called logtop. It is a system administrator tool to analyze line rate taking log file as input. It reads on stdin and print a constantly updated result displaying, in columns in the following format:

Line number, count, frequency, and the actual line

How do install logtop on a Debian or Ubuntu based system?

Simply type the following apt-get command:

$ sudo apt-get install logtop


Sample outputs:

Reading package lists… Done

Building dependency tree

Reading state information… Done

The following NEW packages will be installed:


0 upgraded, 1 newly installed, 0 to remove and 3 not upgraded.

Need to get 15.7 kB of archives.

After this operation, 81.9 kB of additional disk space will be used.

Get:1 precise/universe logtop amd64 0.3-1 [15.7 kB]

Fetched 15.7 kB in 0s (0 B/s)

Selecting previously unselected package logtop.

(Reading database … 114954 files and directories currently installed.)

Unpacking logtop (from …/logtop_0.3-1_amd64.deb) …

Processing triggers for man-db …

Setting up logtop (0.3-1) …


The syntax is as follows:

logtop [OPTIONS] [FILE]

command | logtop

command1 | filter | logtop

command1 | filter | logtop [options] [file]


Here are some common examples of logtop.

Show the IP address flooding your LAMP server

Type the following command:

tail -f www.cyberciti.biz_access.log | cut -d    -f1 | logtop

Sample outputs:

Fig.01: logtop command in action

See squid cache HIT and MISS log

tail -f cache.log | grep -o  HIT\|MISS  | logtop

To see realtime hit / miss ratio on some caching software log file, enter:

tail -f access.log | cut -d    -f1 | logtop -s 20000


The -s option set logtop to work with the maximum of K lines instead of 10000.

See also

Get Detailed Information About Particular IP address Connections Using netstat Command

logtop home page



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