Converting Kilobytes to Gigabytes and vice versa

If you need to do a quick calculation from Kilobytes to Gigabytes and vice versa. Do take a look at
Kilobytes to Gigabytes Conversion Calculator

Subnet Calculator

Subnet Calculator from http://www.subnet-calculator.com/ is a good online tool to calculate subnet

Understanding memory usage with top

If you type "top" on the console,  you will see similar information

Mem:  12299804k total,  1505328k used, 10794476k free,   196024k buffers

How do you interpret the information especially the buffer? The above server has 12GB of RAM

1. About 200Mbytes of memory is in the buffer. This buffering is to speed up disk access by caching written data in memory and reading in more than what we need in anticipation of the next week. If the memory is for more important requirements such as applications, it will be released immediately.

Using read-edid to extract useful information on PnP Monitor on Ubuntu or Linux Mint

Read-edid utility is a useful tool to help you  extract useful information on PnP Monitor.

According to the read-edid website, if you can't find the data to set your monitor up under XFree86, then read-edid is for you; it should auto detect all necessary info and should even provide a few modes with better refresh rates/resolutions than the standard VESA ones. However, as of now it won't do everything for you; you'll have to edit XF86Config yourself.

To install read-edid utility in Ubuntu or Linux Mint, just do a
# aptitude install read-edid OR
# apt-get install read-edid


The  data obtained by get-edid is in a binary format, so the parse-edid command is available to interpret  it  and  generate  a  human-readable block  of  text  information  that  can  also be included in an XFree86 XF86Config file. It is customary  to  invoke  get-edid  and  parse-edid  together  in  a pipeline.
# get-edid | parse-edid


More information:

1. Get-edid Website

Scons - Open Source Construction Tool

SCons is an Open Source software construction tool—that is, a next-generation build tool. Think of SCons as an improved, cross-platform substitute for the classic Make utility with integrated functionality similar to autoconf/automake and compiler caches such as ccache. In short, SCons is an easier, more reliable and faster way to build software.

It has support for Windows and Linux. In particular, for the RHEL distribution, it has the rpm. However, it will need python > 1.5.2. But the user guide recommend Python 2.5 and above

Goldmine of GUI Admin Tools - GadminTools

For first timers to Linux, you may just want to start with some cool GUI Admin Tools, look no further, go to GadminTools (http://gadmintools.flippedweb.com/) and you can download stuff like Gadmin-ProFtpd to configure your Linux FTP

Using mrxvt

mrxvt is a cool alternative terminal emulator. It is extremely flexible and the most interesting feature is the tabbed-oriented design. mrxvt can be easily obtained from a number of distribution.

For more information,

• mrxvt project site
• Juggling Shells (by Linux Magazine)
  

Using vim more effectively

Like many Linux administrator, vim is an editor of choice. However, I fail to exploit the many shortcuts and tricks that make it stand-out. I will list a couple of commands of frequent use

1. Searching
Create a .vimrc in your own home directory. With this you can you place useful commands settings

set incsearch (incremental search function)
set ignorecase (ignore case-sensitive function)
set smartcase (used in conjunction with ignorecase. By default it search for any case unless the user specify uppercase character)

2. Movement from the keyboard.

h (move left)
l (move right)
j (move up)
k (move down)

3. Editing

x (delete the character under the cursor) 
y (copy the characters from the current cursor) 
p (paste previous deleted or copied text after the current cursor position) 
d (delete the characters from the cursor position)

4. File Browser and Screen

e .(To make vim act as a file browser) 
:split (To split the screen into seperate segments. Use Crtl+W and arrow keys to change screen)

5. UsingTab

# vim -p file1 file2 (2 file with tabs will show)

:tabn (next tab) 
:tabp (previous tab) 

6. Spell Check

: setlocal spell spelllang=en_us (enable spell checking)
: help spell (spell help)
]s (Go to the next misspelled word)
z= (Display suggestions for correct spelling)

Interesting Articles:
Vim Introduction and Tutorial

Midnight Commander

Midnight Commander is my favourite Orthodox File Managers. Easy to use and work nicely over SSH or X11.

To install, you can use

# yum install mc

More Information: Midnight Commander Development Center

whohas - Application Finder

whohas is a command line tool that allows you to query several package collections at once. It currently supports Arch Linux (and AUR), Debian, Fedora, Gentoo, Mandriva, openSUSE, Slackware (and linuxpackages.net), Source Mage Linux, Ubuntu, FreeBSD, NetBSD, OpenBSD, Fink, and MacPorts repositories.

Festival - Text to Speech Synthesis Software

Festival is a fun text to speech sysnthesis software. You can make LINUX greet you or your users. Users will be rather intrigued....Ha Ha

Step 1: Install Festival
# yum install festival

Step 2: Make Festival talk from the keyboard
# echo "Hello World." festival --tts

Step 3: Make Festival talk from the text file
# festival --tts filename.txt

Interesting Tutorials

• "Festival: Linux Text-To-Speech Tutorial and Demo" by Xeno Cafe
• The Festival Speech Synthesis System (Offical Website)

Using httping to test http throughput and latency

To test the throughput and latency of a web server from a remote server, you can use the following utilities httping.

Step 1:
Install RPMForge

Step 2:

# yum install httping

Step 3:

# httping -c10 -Grg http://www.yourwebserver.com

Notes:
-g (URL to probe)
-G (GET request, to fetch the whole page)
-r (Resolve the hostname once, removing latency)
-b (show the transfer rates in bytes)
-s (display return codes)
-l (connect using SSL)

Solving "E25: GUI cannot be used: Not enabled at compile time" on CentOS

Solving "E25: GUI cannot be used: Not enabled at compile time"

When you run vim -g , you may encounter the above error "E25: GUI cannot be used: Not enabled at compile time".

Do note that at CentOS, the equivalent of vim -g is gvim. However, there is no package called gvim on CentOS 4 and CentOS 5. To have the gvim equivalent, do the following.

Step 1: yum install vim-enhanced (To install the fuller package of vim)
Step 2: yum install vim-X11 (To installed the equivalent of gvim)
Step 3: Just type gvim......and you have it