64 bit Raspberry Pi 3 complete specs and pricing

A new version of the Raspberry PI 3 has released and it is amazing. It is 10x the performance of Raspberry Pi 1. Here are the complete specs for new 64-bit credit card size computer

The Raspberry Pi 3 Specs

1. SoC – BCM2837
2. CPU – 64-bit 1.2GHz quad-core ARM Cortex-A53 CPU
3. RAM – 1GB SDRAM @ 400 MHz
4. Storage – Micro-SD
5. Wireless (Wifi) + Bluetooth – Integrated 802.11n wireless LAN and Bluetooth 4.1. The wifi is IEEE 802.11b/g/n, supports both 20 MHz and 40 MHz channels, and a maximum transmit and receive rate of 150 Mbps. It also supports Infrastructure mode, Wi-Fi Direct and soft-AP mode. And the wifi security includes WPA, WPA2 (802.11i), AES/TKIP, IEEE 802.1X and WAPI.
6. Ethernet – 10/100 Mbps
7. Video – Yes – VideoCore IV 3D
8. Audio – Yes
9. USB 2.0 – 4 ports
10. GPIO – 40
11. Power – 2.5 Amps
12. Operating system support – Linux and Unix or Windows 10 IoT

But it still doesn’t have SATA, USB3 and Gigabit Ethernet

First RPi3 just costs around $35 (see below) and does come with wifi, ethernet, and a 64 bit quad-core CPU. It is fully supported by Linux and mostly by FreeBSD and other Unix-like systems too. There are other options available if you need performance computer. The RPi3 has awesome community support. So it a good deal for what it is.

Raspberry Pi 3 pricing

The biggest update is a 64 bit Quad Core Broadcom BCM2837 CPU for faster operations. The addition of a BCM43143 WiFi chip BUILT-IN to your Raspberry Pi means no more WiFi adapters. You can use Linux or Unix-like system such as FreeBSD on the Raspberry Pi 3. The price for one Raspberry Pi 3 is listed:

• $35 USD (US)
• £30.00 (UK)
• INR 3000 (India)

Source: RASPBERRY PI 3 ON SALE NOW AT $35

Linux Directory Structure (File System Hierarchy) Explained with Examples

Are you new to Linux ? If so, I would advise you to understand the Linux Directory Structure (File System Hierarchy) first. Don’t panic/scare after seeing the below image (File System Hierarchy). Getting confusion about /bin, /sbin, /usr/bin & /usr/sbindon’t worry, we are here to teach you like a baby.

The Filesystem Hierarchy Standard (FHS) defines the structure of file systems in Unix/Linux, like operating systems.

In Linux everything is a file, we can modify anything whenever it’s necessary but make sure, you should know what you are doing. If you don’t know, what you are doing & did something without knowing anything which will damage your system potentially. So try to learn from basic to avoid such kind of issues on production environment.

• / : The Root Directory – Primary hierarchy root and root directory of the entire file system hierarchy which contains all other directories and files. Make a note / & /root is different.
• /bin : Essential User Binaries – Contains Essential User Binaries, where all the users performing most commonly used basic commands like ps, ls, ping, grep, cp & cat
• /boot : Static Boot Files – Contains boot loader related files which is needed to start up the system, such as Kernel initrd (Initial RAM Disk image), vmlinuz (Virtual Memory LINUx gZip – compressed Linux kernel Executable) & grub (Grand Unified Bootloader). Make a note, its a vmlinuz not a vmlinux vmlinuz – Virtual Memory LINUX, Non-compressed Linux Kernel Executable
• /dev : Device Files – contains all device files for various hardware devices on the system, including hard drives, RAM, CPU, tty, cdrom, etc,. It’s not a regular files.
• /etc : Configuration Files – contains system global configuration files, which affect the system’s behavior for all users when you modifying anything on it. Also having application service script, like (start, stop, enable, shutdown & status).
• /home : User’s Home Directories – Users’ home directories, where users can save their persona files.
• /lib : Essential Shared Libraries – Contains important dynamic libraries and kernel modules that supports the binaries found under /bin & /sbin directories.
• /lost+found : Recovered Files – If the file system crashes (It happens for many reasons, power failure, applications are not properly closed, etc,.) the corrupted files will be placed under this directory. File system check will be performed on next boot.
• /media : Removable Media – Temporary mount directory for external removable media/devices (floppies, CDs, DVDs).
• /mnt : Temporary Mount Points – Temporary mount directory, where we can mount filesystems temporarily.
• /opt : Optional Packages – opt stands for optional, Third party applications can be installed under /opt directory, which is not available in official repository or proprietary software.
• /proc : Kernel & Process Files – A virtual filesystem that contains information about running process (/proc/(pid), kernel & system resources (/proc/uptime & /proc/vmstat).
• /root : Root Home Directory – is the superuser’s home directory, which is not same as /.
• /run : Application State Files – is a tmpfs (temporary file system) available early in the boot process, later files get truncated at the beginning of the boot process.
• /sbin : System Administration Binaries – /sbin also contains binary executable similar to /bin but it’s require superuser privilege to perform the commands, which is used for system maintenance purpose.
• /selinux : SELinux Virtual File System – Security-Enhanced Linux (SELinux) is a Linux kernel security module that provides a mechanism for supporting access control security policies, applicable for RPM based systems, such as (RHEL, CentOS, Fedora, Oracle Linux, Scentific Linux & openSUSE).
• /srv : Service Data – srv stands for service, contain data directories of varies services provided by the system such as HTTP (/srv/www/) or FTP(/srv/ftp/)
• /sys : virtual filesystem or pseudo file system (sysfs) – Modern Linux distributions included a /sys directory, since 2.6.X kernels. It provides a set of virtual files by exporting information about various kernel subsystems, hardware devices and associated device drivers from the kernel’s device model to user space.
• /tmp : Temporary Directory – /tmp stands for Temporary (Temporary Files) – Applications store temporary files in the /tmp directory, when its running/required. Which will automatically deleted on next reboot.
• /usr : User Binaries – Contains binaries, libraries, documentation and source-code for second level programs (read-only user data). Command binaries (/usr/bin), system binaries (/usr/sbin), libraries (/usr/lib) for the binaries. source code (/usr/src), documents (/usr/share/doc).
• /var : Variable – var stands for Variable, It contains Application cache files (/var/cache), package manager & database files (/var/lib), lock file (/var/lock), various logs (/var/log), users mailboxes (/var/mail) & print queues and outgoing mail queue (/var/spool)

Enjoy…)

Ubuntu Keyboard Shortcuts

How to use a keyboard shortcut

Traditionally, keyboard shortcuts are written like so: Alt + F1. This means that you should press the Alt and F1 keys simultaneously. This is normally best achieved by holding down the modifier key (such as Ctrl or Alt or the Super(windows logo) key) and then pressing the second key once. You can then release the modifier key.

Finding keyboard shortcuts

Finding system keyboard shortcuts

To find (and change) system-level keyboard shortcuts, one can (at least in later, GNOME-based distros, e.g. ubuntu karmic) run the Keyboard Shortcuts applet, e.g. via System>Preferences>Keyboard Shortcuts on the main menu.

Finding application-specific keyboard shortcuts

While there are many standard keyboard shortcuts (see below), most applications also have keyboard shortcuts which are specific to themselves. These can normally be found in the pull-down menus at the top of the application's screen. The example below shows a menu in OpenOffice.org Writer, with the keyboard shortcuts highlighted:

Desktop shortcuts

This section lists common keyboard shortcuts which you can use to operate parts of the desktop (such as windows and the menu bar).

Alt + F1	Open the Applications menu
Alt + F2	Run an application by typing its name in the box which appears
Prt Sc	(Print Screen) Take a screenshot of the whole screen
Alt + Prt Sc	Take a screenshot of the current window
Shift + Prt Sc	Take a screenshot of a selected rectangle on the screen

Window shortcuts

Alt + Tab	Switch between currently-open windows. Press Alt + Tab and then release Tab (but continue to hold Alt). Press Tab repeatedly to cycle through the list of available windows which appears on the screen. Release the Alt key to switch to the selected window.
Ctrl + Alt + Tab	Switch between currently-open windows in all Workspaces. Press Tab repeatedly to cycle through the list of available windows which appears on the screen. Release the Ctrl and Alt keys to switch to the selected window.
Ctrl + Alt + Left/Right Cursor	Lets you quickly switch between your Workspaces.

These might not work on every machine, but are reasonably common:

Alt+F7	Moves the current window (can be moved with mouse or keyboard).
Alt+F8	Resizes current window (again, can be moved with mouse or keyboard).
Alt+F9	Minimises current window.
Alt+F10	Maximises current window.
Alt+Space	Brings up window menu with with 'Always on Top' and 'Minimise' and 'Maximise' and above commands.

These might change depending on the application you're using, but work for most common applications:

Alt+F5	Returns window to 'normal' or previous size.
Alt+F4	Closes window.

Desktop Effects enabled shortcuts

All of the shortcuts listed in this section require Desktop Effects to be enabled.

Ctrl + Alt + Left/Right Cursor	Spins the 'cube' that your workspaces reside on, allowing you to select the workspace you wish to use.
Ctrl + Alt + Up Cursor	Enables an 'expose' like feature that presents you with all the windows you currently have open, allowing you to select the one you wish to give focus to.
Ctrl + Alt + Down Cursor	Unfolds your workspace cube allowing you to see more than one of your workspaces at once, using the left and right cursor keys with this active will allow you to select the workspace you wish to use.
Ctrl + Alt + Tab	Switch between currently-open windows across all workspaces.
Super + W	Enables the 'scale' effect, it shows all windows from the current workspace.
Super + A	Enables the 'scale' effect, it shows all windows from all workspaces.
Super + N	Invert colours of the focused window.
Super + M	Invert colours for the whole screen.
Super + Mouse Scroll Wheel	Zooms in on the screen.
Super + Middle Mouse Button	Select a region to zoom into, using a rectangle.
Ctrl + Super + D	Toggles 'Show Desktop'.
Alt + Middle Mouse Button	Resize focused window.
Alt + Left Mouse Button	Move focused window.
Alt + Right Mouse Button	Show window menu.
Super + S	Zoom out, show workspace switcher

Common application shortcuts

These shortcuts do not apply in all applications, but usually perform the functions listed below.

Ctrl + C	Copy the selected text/object
Ctrl + X	Cut the selected text/object
Ctrl + V	Paste/insert the selected text/object
Ctrl + A	Select all text
Ctrl + B	Make the selected text bold
Ctrl + I	Make the selected text italic
Ctrl + U	Underline the selected text
Ctrl + N	Open a new document or window
Ctrl + S	Save the current document
Ctrl + O	Open another document
Ctrl + P	Print the current document
Ctrl + Z	Undo the last change you made
Ctrl + Shift + Z	Redo a change that you just undid

System shortcuts

Some of these shortcuts will restart important parts of your system. Only use them if you have to.

Ctrl + Alt + Delete	Restart the computer immediately, without saving open files
Ctrl + Alt + Plus (numeric keypad)	Rotate through supported screen resolutions
Ctrl + Alt + Minus (numeric keypad)	Rotate backwards through supported screen resolutions

Application-specific shortcuts

This section covers common keyboard shortcuts for some important applications which are installed by default in Ubuntu.

Firefox Web Browser

Ctrl + T	Open a new tab
Ctrl + Tab	Rotate through each tab
Ctrl + Shift + Tab	Rotate backwards through each tab
Ctrl + W	Close the current tab (or browser if on last tab)
Ctrl + L	Enter a new web address
Ctrl + B	Show a list of your bookmarks
Ctrl + H	Show your browsing history
Ctrl + K	Enter a new web search in the search bar
Ctrl + Y	Show a list of downloaded files
F11	Display the current page full-screen
Esc	Stop loading the current page
Ctrl + R	Reload the current page

These might not work for everyone, but can help with accessibility issues:

Alt Gr+Space Scrolls current tab/window down.

Alt Gr+Backspace Scrolls current tab/window up. You may find Alt Gr+Shift+Space works if Alt Gr+Backspace does not.

If you don't have Alt Gr, it might be labelled something else. It's usually to the right of the space bar.

See Mozilla Support for a full list of keyboard shortcuts in Firefox.

LibreOffice Writer

F7	Check the spelling of the current document
Ctrl + F	Find and replace words
Ctrl + Z	Undo the last change
Ctrl + Y	Redo a change which you just undid
Ctrl + L	Align the current paragraph/selection to the left
Ctrl + E	Align the current paragraph/selection to the center of the document
Ctrl + R	Align the current paragraph/selection to the right
Ctrl + Shift + J	Show the current document full-screen

Press Tools ▸ Customize… ▸ Keyboard to change keyboard shortcuts in LibreOffice.

Laptop Function Shortcuts

Many laptops have function (Fn) keys which you can hold down to access more functions on the laptop's keyboard. A list of these functions should be available from the manufacturer of the laptop.