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Created by magnum on January 06, 2013 20:15:00
Last update: April 05, 2013 09:59:12
nslookup :
$ nslookup www.google.com
Server: 127.0.0.1
...
dig :
$ dig +noall +answer www.google.com
www.google....
host
$ host www.google.com
www.google.com has addres...
About the use of reverse DNS from webdnstools.com :
Many things use reverse DNS. An example is anti-spam email software. Before delivering an email, it is common for anti-spam software to perform a reverse DNS lookup on the IP address of the source mail server. It then checks that the reverse DNS entry matches the SPF record provided by the name server of the source email domain. If it does not match, it may flag the email as spam.
Created by voodoo on March 15, 2013 08:43:00
Last update: March 15, 2013 08:43:00
In ubuntu 12.10 dnsmasq is started automatically by the network manager. This is how to disable it:
Edit the network manager configuration:
$ sudo vi /etc/NetworkManager/NetworkManager.conf
Comment out the line with dnsmasq:
[main]
plugins=ifupdown,keyfile
#dns=dnsma...
Restart the network manager:
$ sudo restart network-manager
Created by magnum on March 03, 2013 13:27:54
Last update: March 03, 2013 13:27:54
Suppose you have a very large log file and it's hard to load the whole file into an editor. But you know the range of lines you are interested in. You can use sed to extract the range of lines to a smaller file:
$ sed -n 2737172,2743667p proxy.log > proxy-short....
The switch -n means 'quiet', suppress automatic printing of pattern space .
You can also use regex to mark the start and end lines instead of absolute line numbers.
Created by Dr. Xi on February 13, 2013 19:40:08
Last update: February 13, 2013 19:40:08
According to MSDN : On Windows 7 and on Windows Server 2008 R2 with the Wireless LAN Service installed, the operating system installs a virtual device if a Hosted Network capable wireless adapter is present on the machine. This virtual device normally shows up in the "Network Connections Folder" as "Wireless Network Connection 2" with a Device Name of "Microsoft Virtual WiFi Miniport adapter" if the computer has a single wireless network adapter. This virtual device is used exclusively for performing software access point (SoftAP) connections. The lifetime of this virtual device is tied to the physical wireless adapter. If the physical wireless adapter is disabled, this virtual device will be removed as well. On Windows 7, there's no UI to start or stop SoftAP....
Created by James on November 01, 2012 13:51:42
Last update: November 01, 2012 13:51:42
One way to vertically center a line of text in a container div is to set line-height to be the same as the height of the container. But that requires specifying line-height in pixels. This technique avoids that.
<!doctype html>
<html>
<head>
<style typ...
Created by magnum on October 22, 2012 19:54:43
Last update: October 22, 2012 19:54:43
Example 1, from the pipe man page. The parent then writes the string contained in the program's command-line argument to the pipe, and the child reads this string a byte at a time from the pipe and echoes it on standard output.
#include <sys/wait.h>
#include <stdio.h>
#in...
Example 2, child execs command given at the command line, then writes to stdout (of child), which is piped to parent. Parent reads from pipe and writes to stdout (of parent).
#include <sys/wait.h>
#include <stdio.h>
#in...
Created by voodoo on September 25, 2012 19:33:02
Last update: September 25, 2012 19:33:02
This a step-by-step example of how to create the files for GNU automake. Put the C source file in directory src ( cat src/hello.c ):
#include <config.h> #include <stdio.h> ... Run autoscan to generate configure.scan . Rename configure.scan : mv configure.scan configure.ac Edit autoscan.ac . Update this line: AC_INIT([FULL-PACKAGE-NAME], [VERSION] , [BUG-REP... Add this line after AC_INIT : AM_INIT_AUTOMAKE([foreign -Wall -Werror]) Add this line before AC_OUTPUT : AC_CONFIG_FILES([Makefile src/Makefile]) Create file Makefile.am ( cat Makefile.am ): SUBDIRS = src Create file src/Makefile.am ( cat src/Makefile.am ): bin_PROGRAMS = hello hello_SOURCES = hello.c Run these commands: $ aclocal $ autoheader $ automake --add-miss... The file configure is generated after autoconf is run. Build with: $ ./configure $ make Create tarball for distribution with: $ make dist...
Created by magnum on September 11, 2012 11:59:43
Last update: September 11, 2012 11:59:43
Exerpt from bash documentation. HISTORY EXPANSION The bash shell supports a history expansion feature that is similar to the history expansion in csh. This feature is enabled by default for interactive shells, and can be disabled using the +H option to the set builtin command. Non-interactive shells do not perform history expansion by default. History expansions introduce words from the history list into the input stream, making it easy to repeat commands, insert the arguments to a previous command into the current input line, or fix errors in previous commands quickly. History expansion is performed immediately after a complete line is read, before the shell breaks it into words. It takes place in two parts. The first is to determine which line from the history...
Created by magnum on September 11, 2012 11:55:43
Last update: September 11, 2012 11:55:43
Excerpt from bash documentation. Quoting is used to remove the special meaning of certain characters or words to the shell. Quoting can be used to disable special treatment for special characters, to prevent reserved words from being recognized as such, and to prevent parameter expansion. There are three quoting mechanisms: the escape character , single quotes , and double quotes . A non-quoted backslash (\) is the escape character. It preserves the literal value of the next character that follows, with the exception of <newline> . If a \<newline> pair appears, and the backslash is not itself quoted, the \<newline> is treated as a line continuation (that is, it is removed from the input stream and effectively ignored). Enclosing characters in single quotes preserves the...
Created by voodoo on August 15, 2012 11:23:44
Last update: August 15, 2012 11:23:44
By default Linux pipe output is buffered. For example, you can't see the most recent stdout on screen with tee :
$ ./mycommand | tee /tmp/mycommand.log
Here are two ways to make the pipe unbuffered.
Method 1: use the unbuffer command from expect
$ sudo apt-get install expect-dev
$ unbuffer ./...
Method 2: use stdbuf
# Make output line buffered:
$ stdbuf -oL ./myc...
