Friday, 27 October 2017


#HTTP Proxy/FTP Proxy

# export http_proxy=http://<proxy-server-ip-or-dns-name>:<Port-Number>

# export ftp_proxy=http://<proxy-server-ip-or-dns-name>:<Port-Number>

# vi /etc/bash.bashrc
export http_proxy=http://<proxy-server-ip-or-dns-name>:<Port-Number>/
export ftp_proxy=http://<proxy-server-ip-or-dns-name>:<Port-Number>/

# Proxy Settings in APT on Ubuntu Linux

# vi /etc/apt/apt.conf
Acquire::http::Proxy "http://<proxy-server-ip-or-dns-name>:<Port-Number>";


# export RSYNC_PROXY="http://<proxy-server-ip-or-dns-name>:<Port-Number>”

# For Git Clone 

#vi ~/.gitconfig
    proxy = http://username:password@<proxy-server-ip-or-dns-name>:<Port-Number>

#Yum Proxy setting

vi /etc/yum.conf


#DNF proxy setting

vi /etc/dnf/dnf.conf



vi ~/.curlrc

proxy = http://username:password@<proxy-server-ip-or-dns-name>:<Port-Number>

Sunday, 22 October 2017

Proxy setting in Browsers - Internet Explorer, Firefox, Chrome

1) Internet Explorer 

2) Firefox

3) Chrome

Installation of Kernel from source file

Download the latest tar source files:

Copy the file to /usr/src location

  • tar -xvzf [file name]
  • cd /usr/src/
  •  make menuconfig\
Exit from the window and save the kernal

  • make bzImage
  • make
  • make modules
  • make modules_install
  • make install


 "make bzImage" command sometimes fails, install dependency libraries.

scripts/sign-file.c:23:30: fatal error: openssl/opensslv.h: No such file or directory
#include <openssl/opensslv.h>
compilation terminated.
make[1]: *** [scripts/sign-file] Error 1
make: *** [scripts] Error 2

yum install openssl / dnf install openssl

Install kernel headers and kernel developmental tool in Fedora

Give the uname -r and copy the kernel version and fedora version
   Ex. # uname -r

Copy "4.8.6-300.fc22.i686" and replace in the below command instead of 'uname -r'

dnf install kernel-headers- `uname -r` kernel-devel- `uname -r`

How to stop Kernel from assigning random Interface names

In order to ensure the the kernel uses the name assigned to it, below command can be used:

On Ubuntu

ln -s /dev/null /etc/udev/rules.d/80-net-setup-link.rules

In Fedora:

ln -s /dev/null /etc/udev/rules.d/80-net-name-slot.rules


Change MAC address of Bluetooth Dongle

Download the tool 
  • Kernel should be 4.X or above versions.
  • Download bdaddr from below website:
  • bdaddrtar.bz2
  • tar xvf bdaddrtar.bz2
  • cd bdaddr 
  • make


  The "bdaddr" application is generated which can be used to change MAC address of dongle.

  1. Insert dongle and make interface up 

hciconfig -i hci0 up

      2./bdaddr ==> it will show current mac address
  root@bt:# ./bdaddr
Manufacturer: Cambridge Silicon Radio (10)
Device address: 00:50:F2:7E:2F:9B
      3.To change mac address give new MAC address as below
         root@bt# ./bdaddr -i hci0 00:01:E3:64:DD:9B
Manufacturer: Cambridge Silicon Radio (10)
Device address: 00:50:F2:7E:2F:9B
New BD address: 00:01:E3:64:DD:9B

Address changed - Reset device now

     4.Re -connect the dongle it should show new MAC address.

Note: If any dependency error install BlueZ, otherwise not required.

  •  Install BlueZ
  •  tar xf bluez-5.46.tar.xz 
  •  cd bluez-5.46 
  •  ./configure --enable-test
  •  make 


Loading a developmental kernel Snap

The command to load the kernel snap is :

#snap install Snapped 96boards-kernel_XXX_arm64.snap --dangerous

Once in a while there is error in loading the kernel, in that case below workaround can be used.

Get the name of  existing kernel snap

# snap list kernel-name

Back up the existing kernel

# cp /var/lib/snapd/snap/kernel-name-version1.snap ~/

Replace the developing kernel to current kernel snap.

# sudo cp <new kernel snap> /var/lib/snapd/snaps/kernel-name-version1.snap

Reboot the system and test it

# sudo reboot

If it doesnt boot up, restore the old snap.

# sudo cp kernel-name-version1.snap /var/lib/snapd/snaps/kernel-name-version1.snap

Installing Kernel header files in ubutntu

  1.  sudo apt-get install linux-headers-4.3.XX-generic
  2.  The header files will be installed in /lib/modules/4.3.XX-generic/build