Online, web based spreadsheets

Simple Spreadsheet
Sheetster Web Spreadsheet
ZK Spreadsheet

Wikipedia: online spreadsheet
 Also try Zimbra collaboration suit


How to Format a Hard Drive in Linux

When you format a computer hard drive, you will lose everything that is on the drive!!! Therefore it is very important to back up anything you might later want!!!

Linux refers to hard drives as either "hdx" or "sdx" where x is a letter, starting with a, which represents the order in which the drive was added to or detected by the computer. The "hd" prefix is used for IDE and PAT), and the "sd" prefix is used for SCSI, SATA, and USB drives. Usually a number is also put at the end of "hdx" or "sdx" to denote different partitions on the same phisical drive, but for the purpose of formatting you only need to know which letter the drive you want to format is.

All actions done with root privileges.
You can check which drives are represented in your system. Do following commands:
ls /dev/hd*
   or (depending on which type of drive)
ls /dev/sd*
Simple output: /dev/hda  /dev/hda1  /dev/hda2  /dev/hdb  /dev/hdb1  /dev/hdd
# fdisk -l
Disk /dev/hda: 80.0 GB, 80000000000 bytes
255 heads, 63 sectors/track, 9726 cylinders
Units = cylinders of 16065 * 512 = 8225280 bytes

   Device Boot      Start         End      Blocks   Id  System
/dev/hda1   *           1          13      104391   83  Linux
/dev/hda2              14        9726    78019672+  8e  Linux LVM

Disk /dev/hdb: 40.0 GB, 40020664320 bytes
255 heads, 63 sectors/track, 4865 cylinders
Units = cylinders of 16065 * 512 = 8225280 bytes

   Device Boot      Start         End      Blocks   Id  System
/dev/hdb1               1        4865    39078081   83  Linux
In this examples we can see that the operating system is installed on hda, which has two partitions (hda1 and hda2), and there is one partition on hdb - hdb1.

Firefox' about:conf tricks + Bonus extension

Spell Check Single Line Fields
  • In address bar type: about:config.
  • In the “Filter” field type layout.spellcheckDefault.
  • As you can see it has value of "1". Double click on it and enter 2 as its new value.
  • Restart firefox. 
Address bar as Search BOX
Yes in Mozilla Firefox you can just type your search query in address bar and get the search results displyed to you!
For this:
  • Type about:config in address bar of Mozilla Firefox.
  • Type keyword.URL in filter box.
  • Right-Click on that line and select modify option.
  • Enter any of the following string for corresponding search engine!(Google's Feeling lucky is my favorite, and it's by default)
Google: Feeling Lucky - http://www.google.com/search?ie=UTF-8&oe=UTF-8&sourceid=navclient&gfns=1&q=
Vanilla Google - http://www.google.co.in/search?btnG=Google+Search&q=
Wikipedia -  http://en.wikipedia.org/wiki/Special:Search?fulltext=Search&search=
Wikipedia: Feeling Lucky - http://en.wikipedia.org/wiki/Special:Search?go=Go&search=
Yahoo -  http://search.yahoo.com/search?p=
(Default Firefox en-US keyword URL: http://www.google.com/search?ie=UTF-8&oe=UTF-8&sourceid=navclient&gfns=1&q=)


File permissions in linux - explained

Linux is often used as a multi-user system and it is not desirable that all users have access to all files and directories.
For eg. : On a multi-user environment in a office using a central server running linux , it might be required the accountants documents be shared between employees of the accountants department . At the same time, it might be undesirable and indeed dangerous if anyone having access to the server is able to read/edit them.

Linux has a 3X3 permission system.

There are 3 levels of security for a file :

Read Permission : Permission to read a file (r)
Write Permission : Permission to edit a file (w)
Execute Permission : Permission to execute a file if it is executable (x)

and 3 different levels for a directory :

Enter Permission : Permission to Enter into the Directory
Show Entry : Permission to see the contents of the Directory
Write Entry : Permission to make a new file or subdirectory in the Directory

For granting the above permissions, users are divided into 3 different sets

User : The owner of the file/directory - mostly the person who created the file/directory
Group : Linux users can be divided in groups and one user can be a member of more than one group. A Group denotes all users who are members of group(s) to which the owner of a file/directory belongs
Others : All users not in the group(s) of the owner.


My Firefox Addons Collection

Collection of most useful and powerful addons i've ever used and suggesting to other.
I've tried to collect addons which are helping power users or admins to save time during surfing on the web.
No funky shit, 3d Effects, or whatever design enhancements, except my favorite theme and some additional buttons. Yeap there are some addons which i'm not using but think that they are good and maybe useful for someone else except me.
Collection contains 84 addons and amount is growing while i'm finding more and more usefull extensions.

Link to my firefox collection: Power User Pack

List of some addons in my collection:
- TabMixPlus
- FlashGot
- Firebug
- Download Status Bar
- Enhaced Status Bar
- ScreenGrab
- ImageZoom
- Hide Menu Bar
- Quick Restart
- Fast Dial
- All In One Sidebar
- Check Places
- NoScript
- TreeStyle Tab
and much more other cool extensions.

Here is how my FF looks:


Working in linux terminal

Virtual terminals
Ctrl + Alt + F1 - Switch to the first virtual terminal. In Linux, you can have several virtual terminals at the same time. The default is 6.
Ctrl + Alt + Fn - Switch to the nth virtual terminal. Because the number of virtual terminals is 6 by default, n = 1...6.
tty - Typing the tty command tells you what virtual terminal you're currently working in.
Ctrl + Alt + F7 - Switch to the GUI. If you have the X Window System running, it runs in the seventh virtual terminal by default in most Linux distros. If X isn't running, this terminal is empty.
Note: in some distros, X runs in a different virtual terminal by default. For example, in Puppy Linux, it's 3.

Command line - input
Home or Ctrl + a Move the cursor to the beginning of the current line.
End or Ctrl + e -  Move the cursor to the end of the current line.
Alt + b         - Move the cursor to the beginning of the current or previous word. Note that while this works in virtual terminals, it may not work in all graphical terminal emulators, because many graphical applications already use this as a menu shortcut by default.
Alt + f         - Move the cursor to the end of the next word. Again, like with all shortcuts that use Alt as the modifier, this may not work in all graphical terminal emulators.
Tab             - Autocomplete commands and file names. Type the first letter(s) of a command, directory or file name, press Tab and the rest is completed automatically! If there are more commands starting with the same letters, the shell completes as much as it can and beeps. If you then press Tab again, it shows you all the alternatives. This shortcut is really helpful and saves a lot of typing! It even works at the lilo prompt and in some X applications.
Ctrl + u        - Erase the current line.
Ctrl + k        - Delete the line from the position of the cursor to the end of the line.
Ctrl + w        - Delete the word before the cursor .
Ctrl + t             -  Switch 2 characters on a command line. If you typed sl, put the cursor on the l and hit ctrl+t to get ls.
Ctrl + b           - Moves to the beginning of the previous or current word

Command line - output
Shift + PageUp - Scroll terminal output up.
Shift + PageDown - Scroll terminal output down.
clear - The clear command clears all previously executed commands and their output from the current terminal.
Ctrl + l - Does exactly the same as typing the clear command.
reset If you mess up your terminal, use the reset command. For example, if you try to cat a binary file, the terminal starts showing weird characters. Note that you may not be able to see the command when you're typing it .
Ctrl+S Ctrl+Q - terminal output lock and unlock. These are simple shortcuts to pause and continue terminal output, works in most terminals and screen multiplexers like screen. You can use it to catch something if things change too fast, and scroll with Shift + PgUp PgDown. On linux console ScrollLock can also be used.

Command line - history
history - When you type the history command, you'll see a list of the commands you executed previously.
ArrowUp or Ctrl + p - Scroll up in the history and edit the previously executed commands. To execute them, press Enter like you normally do.
ArrowDown or Ctrl + n - Scroll down in the history and edit the next commands.
Ctrl + r - Find the last command that contained the letters you're typing. For example, if you want to find out the last action you did to a file called "file42.txt", you'll press Ctrl + r and start typing the file name. Or, if you want to find out the last parameters you gave to the "cp" command, you'll press Ctrl + r and type in "cp".
Sudo !! - Run last command as root

Command line - misc
Ctrl + c - Kill the current process.
Ctrl + z - Send the current process to background. This is useful if you have a program running, and you need the terminal for awhile but don't want to exit the program completely. Then just send it to background with Ctrl+z, do whatever you want, and type the command fg to get the process back. 
Ctrl + d - Log out from the current terminal. If you use this in a terminal emulator under X, this usually shuts down the terminal emulator after logging you out.
Ctrl + Alt + Del - Reboot the system. You can change this behavior by editing /etc/inittab if you want the system to shut down instead of rebooting.

Originals: TuxFiles + Bonuses


Command LOCATE usage and errors fixing

Need to find a file fast on a linux filesystem? Use the linux locate command
[root@localhost /]# locate openssl
Possible error during command initialization:
locate: can not open `/var/lib/mlocate/mlocate.db
Type updatedb to fix this problem
[root@localhost /]#updatedb