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Get HTTP request with nc command

Dec 222010

Get HTTP request with nc command

Answer:

nc command is a very useful tool for network diagnosis, e.g. when you want to know the exact requests sent by your HTTP client (e.g. browser) to your web server, you can easy test with nc.

1. In your server, start nc and listen on port 80

# sudo nc -l -p 80

2. In your browser, type the server IP address.

3. In your shell, HTTP requests will be printed.

GET / HTTP/1.1
Host: example.com
User-Agent: Mozilla/5.0 (Windows; U; Windows NT 6.1; en-US; rv:1.9.1.3) Gecko/20090712 Firefox/3.5.3
Accept: text/html,application/xhtml+xml,application/xml;q=0.9,*/*;q=0.8
Accept-Language: en-us,en;q=0.5
Accept-Encoding: gzip,deflate
Accept-Charset: ISO-8859-1,utf-8;q=0.7,*;q=0.7
Keep-Alive: 115
Connection: keep-alive

What are the difference between tail -f and tail -F?

Commands No Responses »

Dec 152010

What are the difference between tail -f and tail -F?

Answer:

Basically these two command are very similar, except tail -F do one more thing: the retry.

This is useful when you are tailing a web server log, e.g. apache log. When the the log file got rotated, the tail -F will continue to work since it will retry for the rotated file, while tail -f can't.

List the size of sub directories in the current directory

Commands 1 Response »

Dec 132010

List the size of sub directories in the current directory

Answer:

To check the disk usage of all sub directories in the current directory, you can try the following method:

#  sudo du -h --max-depth=1

4.0K    ./src
341M    ./lib
68M     ./bin
24K     ./games
195M    ./share
36M     ./local
18M     ./sbin
18M     ./include
673M    .

How to kill and logout a logged in user

Commands No Responses »

Dec 122010

How to kill and logout a logged in user

Answer:

Assume john is logged in and you want to terminate his session, you can use the skill command.

# sudo skill -KILL -u john

Extract a bzipped tar file

Commands No Responses »

Dec 102010

Extract a bzipped tar file

Answer:

Normally tar is combined with gzip as the most common usage, however, sometimes people use bzip2 instead for maximum compression rate. File in such format usually have the file name like: program.tar.bz2

To extract it using a single command:

# tar -jxvf program.tar.bz2

The key is the argument - j

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