Finding the bit version of Ubuntu

In order to find out which version of your Ubuntu is (that is 32 bit or 64 bit) , we can write in the terminal

                        file /sbin/init
It will tell us the version of Ubuntu as shown below mine is 32 bit

Xampp Error you need to uninstall/disable/reconfigure the blocking application

While installing Xampp on windows i got the following error

[Apache]    Problem detected!
[Apache]    Port 443 in use by "Unable to open process" with PID 4!
[Apache]    Apache WILL NOT start without the configured ports free!
[Apache]    You need to uninstall/disable/reconfigure the blocking application
[Apache]    or reconfigure Apache and the Control Panel to listen on a different port

----------------------------------

So what I did to resolve this error , I went to Apache (httpd.conf) and changed the port number 

from 80 to 1337 or any other number you like, For this find the line

Listen 80 and change it to

Listen 1337 

For Apache (Httpd.conf) 
on your XAMPP control panel, 

          next to apache, select the "Config" option and select the first file (httpd.conf):

Save the File

Then open the file "Apache (httpd-ssl.conf)" find this following Line

Listen 443

Just change it to something like 7331.

Close the Xammp and then rerun it again. 

Its done

Sometime you may need to go to user account control and disable the UAC and then follow the 

above procedure

Getting Bios Settings of Toshiba Satellite U920T

I was wondering how to get to the bios settings in order to change the boot menu from SSD/HDD to USB. I tried F2, F1, Del and Esc but I was in no success

In order to go to bios settings I did the following trick after Hit and Trial Method

I restarted my system having Windows 8 installed and then kept the F2 pressed when it was off till it started booting and I got the menu, 
(make sure to press F2 before turning on the computer and not after it starting the boot).

So in easy way when your system is turned off, press F2 and then turn on the power button keeping the F2 pressed

With this you will get into the booting menu. 

roscd command not found

If you face the error " roscd command not found " , after ROS installation, this means that your .bashrc doesn’t contain the link to setup.sh, so open the .bashrc file with the following command

gedit .bashrc

then add the following line

source /opt/ros/groovy/setup.bash

as I was working with groovy else add your distribution name like fuerte, electric or hydro

updating the rosdistro that is out of date

While I was installing the ROS (Groovy) , I face the error that said unable to process source or error loading sources or operation time out. I found out that my ROS distribution is out of date so I have to update it. so the following command can be used.

sudo easy_install rosdep

The error obtained previously before was as follows
reading in sources list data from /etc/ros/rosdep/sources.list.d
ERROR: unable to process source [https://github.com/ros/rosdistro/raw/master/rosdep/osx-homebrew.yaml]:
    <urlopen error timed out> (https://github.com/ros/rosdistro/raw/master/rosdep/osx-homebrew.yaml)
Hit https://github.com/ros/rosdistro/raw/master/rosdep/gentoo.yaml
Hit https://github.com/ros/rosdistro/raw/master/rosdep/base.yaml
ERROR: error loading sources list:
    The read operation timed out

removing a folder in ubuntu

In order to delete the folder from command line , if the floder is not being deleted we can use the following command on command line

sudo rm -r [FolderName]

for example

sudo rm -r ros

Un Installing ROS completely from system in Ubuntu

In order to un-install ROS completely from system the following command can be used

sudo apt-get remove ros-*

or if you need to remove specific version then Like for electric

sudo apt-get remove ros-electric-* 

You have to edit .bashrc to remove all the calls or variables set in there for ROS, 

Remove any setup scripts also delete the workspaces created when working with ROS.

If there is some unused dependecies left then the following can be used

sudo apt-get autoremove

Extracting Images from Video

In order to extract the images(Frames) from videos, we can use avconv. It very easy just get the video and then run the following command on video

Let say I have a following video named p.MPG and i want images to make



Open the command prompt









and then write the following command

 avconv -i p.MPG p1%d.jpg

Here p.MPG is the video name while the images name will be starting from p11 and so on. We can keep other names like WeddingPictures1 and so on

avconv used in generating images "avconv -i x.mpg p%d.jpg

 







thus we will get the images as shown in the picture below