Avinash Raj's questions

I try to find the size of my disk, so i runned the below command

$ sudo fdisk -s /dev/sda
976762584

It shows like above. I think the size(976762584) of the disk is shown in kilobytes. How do i convert the value to megabytes or gigabytes through terminal for better understanding?

I already turned on my bluetooth by running sudo rfkill unblock bluetooth command on terminal.I want to turn on my blutooth visibility mode also, so that only my device will get detected.All i have to do from command-line.

How to turn on and off Bluetooth's visibility mode in Ubuntu 14.04 from command-line?

$ lsb_release -c
Codename:   trusty

$ cat /etc/issue
Ubuntu 14.04 LTS \n \l

$ cat /etc/lsb-release
DISTRIB_ID=Ubuntu
DISTRIB_RELEASE=14.04
DISTRIB_CODENAME=trusty
DISTRIB_DESCRIPTION="Ubuntu 14.04 LTS"

Output's of the above commands shows only the partial code name (ie, trusty). How do I get the full codename (trusty tahr) of my installed Ubuntu system?

I installed many packages from many PPAs on my system. I want to list all the installed packages which are installed from launchpad PPAs, not repositories.

Is this possible through command-line?

$ type if
if is a shell keyword

I don't know the other shell keywords.

Is there any command to list all the bash shell keywords.?

Note: help -m displays both shell builtins and shell keywords.

When I run these two commands, I get

$ type cd
cd is a shell builtin
$ type if
if is a shell keyword

It is clearly shown that cd is a shell builtin and if is a shell keyword. So what is the difference between shell builtin and keyword?

While running the complete command on my gnome-terminal, it shows some commands.What are they? And what is the use of complete command?

$ complete
complete -F _minimal 
complete -F _filedir_xspec oodraw
complete -F _filedir_xspec elinks
complete -F _filedir_xspec freeamp
complete -F _longopt split
complete -F _longopt sed
complete -F _longopt ld
complete -F _longopt grep
complete -F _service /etc/init.d/vboxweb-service
complete -F _service /etc/init.d/vboxballoonctrl-service
complete -F _service /etc/init.d/rc
complete -F _service /etc/init.d/nmbd
complete -F _service /etc/init.d/halt
complete -j -P '"%' -S '"' jobs
complete -d pushd

List goes long, so i posted some of the them.

I accidentally deleted my /etc/fstab file by running sudo rm /etc/fstab. Without realising what I'd done, I shut down my Ubuntu OS.

Now I'm not able to boot.

My screen looks like this. In some cases, a purple screen appears. Please give me some solutions.

When trying to move a test_dir directory to /dev/null, I get the message

mv: cannot overwrite non-directory ‘/dev/null’ with directory ‘test_dir/’

Then why do people say "Don't run the command sudo mv ~ /dev/null, it will move your home directory to a hole?"

Link

But /home is also a directory.

I want to replace the 5th line of multiple text files (file1.txt,file2.txt,file3.txt,file4.txt) with the string " Good Morning " using a single terminal command.

All the text files are located on my ~/Desktop.

Note: My desktop consists of 6 .txt files.I want to apply the change to above mentioned 4 text files only.

I added a directory path to system path($PATH) by running,

export PATH=$PATH:/home/avinash/Desktop/raj

Now my path look like this,

$ echo $PATH
/usr/lib/lightdm/lightdm:/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin:/usr/games:/usr/local/games:/home/avinash/Desktop/raj

I want to remove /home/avinash/Desktop/raj from system path variable by using command(like export command does on adding path).

I had created many symbolic links on various paths for a particular file or a directory. I want the whole list of created symbolic links paths (location).

Example:

I created symbolic links for ~/Pictures directory on many directories. How do I list all the symlinks to that ~/Pictures directory?

Is that possible? If yes, then how?

I am running Ubuntu on my laptop.

In case if I lose my laptop or it gets stolen, is there any way to locate it?
Do I have to install any application beforehand to find my laptop?

I installed xdotool by running sudo apt-get install xdotool and throw xdotool key ctrl+alt+t command to open a new terminal window from the current one.But it was not working.

What was the command to open a new terminal window from the current gnome-terminal?

I want to see the contents (list of files and folders) of an archive, for example a tar.gz file without extracting it.

Are there any methods for doing that?

I want to find the current weather of a particular city or my location from terminal. Is there any command-line weather app?

Is there any other method to find all the attached devices UUID through terminal(other than using the blkidcommand ?

Is it possible to open a new tab in the current terminal with some commands?

Is there any way to create a bootable Ubuntu USB flash drive from the terminal without using any third-party applications like YUMI, Unetbootin, Startup Disk Creator, etc.

I tried to create a bootable Ubuntu flash drive with dd method,

sudo umount /dev/sdb
sudo dd if=/path/to/ubuntu.iso of=/dev/sdb bs=1M

It creates files on the USB disk, but when I try to boot the USB disk it shows an Operating System Not Found error.

I want to clear my firefox cache and cookies from terminal.
What can i do?