The following notes explain some of the options open to new-comers to the Raspberry Pi minature computer.

       The Raspberry Pi uses the Linux OperatingSytem (OS) and its microprocessor is a member of the ARM family. This processor has

       a machine code based on the principle of 'Reduced Instruction Set'

       (RISC), when compared with with other processors , e.g Intel's various family members.



      More Information

      Raspberry Pi Foundation please see link





      The Raspberry Pi may be purchased on-line from:-

       Modmypi Please see link

      Element14 please see link

       RS Components please see link



       Notes for Saturday 4th January 2014


       Once Raspberry Pi has been connected to the internet

      the correct time is automatically set

      Substitutions ie short cuts are best made using

      the definition (see alias, below)




      Normally cp will copy files from SOURCE TO DEST

      However, if we wish to include all directories

      in the copy, we must use cp -R SOURCE DEST



      # alias


      name () (command)


      eg rbt () (sudo reboot) will reboot the system



      To make an app work at every session, enter

      the required bash command at the end of the

      bashrc file.

      This file is found in the dir 'etc'.

      cd /etc;ls You must have root permission to

      alter the contents this file.



      The leafpad editor is in the folder - Applications

      There is path to it directly from Raspberrypi folder



      To make a file executable where appropriate use


      chmod +x


      To make a file readable and writeable use


      chmod =rw


      To close a Window can use Alt+F4


      Whilst in LX-Terminal system you can

      return to the Desktop by using 'exit'

      note: this command is case sensitive


      Partition table can be viewed by typing

      sudo fdisk -l (Note option is lower case 'L'

      and Not -1!!)


      To make a permanently executable write:-

      'sudo cp /usr/local/bin

      Make sure has the correct mode +x set


      Useful batch type file can be built as follows:-

      Open a new named and write:-



      no terminator statement is required



      Note: where the syntax $() is used,

      there is no space between the '$' an the '('


      When assembling code which enables the vfp

      coprocessor, the assembler 'as' doesn't work

      Use the gcc compiler instead. The format is:-


       gcc -g -o


      In order to read a pdf file - ,pdf

      use xpdf .pdf


      File listing.

      To get block size use:-

      ls -s --size or simply ls -s


      In order to remove a directory, use the command

       rm -r

      note that in the 'c' statement'printf', if a variable is to be printed

      with a description string, the variable will be printed at the exact position

      of the printing tag %. e.g.


      printf("The name of the input file is :- %s", argv[i]


      full details of file systems in use, including media files

      the later will show from any usb 'plug-ins'

      must use super-visor permission:-

      sudo gparted



      Note: The default version of python is python2.7.

      However the latest ver is python3.2

      In order see the modules available, it is necessary to

      open /usr/lib

      A list of modules is then available by doing an ls

      here. Tkinter (dir) then shows



      In order to keep the current tkinter running

      the last instruction in the module listing

      must be:




      otherwise the graphics window will collapse before

      it is seen!



      Care must be taken when coding python projects

      e.g. tkinter is not available on python2 and

      pygame.py is not available on python3 !



      Importing new modules into python is not

      as straight-forward as it may seem. This is

      because there are several version of python

      all with different libraries.

      e.g. importing 'livewires' from py3e_software

      it is necessary to make a new directory

      'livewires' in the python2.7 library

      use sudo mkdir here.

      Then go back and sudo cp the contents of the

      livewires folder into the new lib folder

      'livewires'. This necessay as we also need

      'pygame'. Then it all works!




      The output is of the form:



      'png' is an image format. In order to see

      the image, needs must find the 'png'

      file in file manager mode and click on it

      e.g. plot2x.png

      GIMP can also be used to show these images


      Scope of 'find' may be increased by using a

      depth parameter e.g. find -O2 qqqqq


      Apps which have been installed (during use)

      are stored in usr/bin directory.

      Apps which were installed on Debian originally

      are stored in bin directory

      Apps which were compiled by the user

      are stored usr/local/bin directory







      This command gives details of local area network


      If you know the four digit IP address of a particular web-site


      traceroute or

      eg Google.com or


      Local Gateway


      The IP address of the internet provider is the Gateway



      When a 'batch' type file is executed,

      the file names appearing on the command line are

      designated as follows:-

       First $0

      3rd $2





      If an exxecutable file in above dir has been mistakenly

      installed in a dir, rm the file in that dir.

      Then change to the desired dir and


      cp /usr/local/bin/ .




      Once exe files are enabled, they cannot be re-edited

      copied or changed. This problem can be over-ridden

      by making a copy of the original txt before processing

      eg :- cp $0 $0.arch

      The *.arch file can then be developed further

      if required, without having to re type the code




      The number of ping shots may be spcified:


      ping -c12




New Raspberry Pi model 2 is now released. Full details on:- please see link