HISTORY:-              

      LINUX IS BASED ON COMMAD LINE OR ___CLI _ MODE OR CBI__ MODE WE

      OPERATE LIUUX IN GUI ____ GRAPHICAL UNIT INTERFACE MODE OR

      CLI ___COMMAND LINE INTERFACE ______ MODE

POINTS ABOUT LINUX___________________________________________________

     

1__LINUX IS A SERVER OPERATING SYSTEM .

2__THERE ARE 80 OPERATING SYSTEMS ARE WORKS IN THE WORLD.

3__70% OF O/S SYSTEMS ARE SERVER OPERATING SYSTEM.

4__30% ARE OF O/S ARE CLINT O/S N OTHER O/S.

5__71% OF WEBSIETS ARE RUNING ON THE APACHE SERVER WHICH IS

      BASED ON THE LINUX O/S.           

6__29% OF WEBSITES ARE RUNNING ON THE OTHER SERVER O/S.

[FOR INFORMATION ABOUT LINUX__ LOGON TO WWW.WIKIPEDIA.ORG]

WWW.KERNAL.COM, WWW.FSF.COM.

OPRATING SYSTEM                                                      INVENTER COMPANY

LINUX______________________________________REDHAT.

AIX________________________________________IBM.

WINDOWS, ZANIX___________________________MICROSOFT.

HP-UX_____________________________________HP.

NETWARE__________________________________NOVELL.

SUN SOLARIS_______________________________SUN.

SUN HAVE THE MOST COSTLY O/S IN THE WORLD THEY HAVE RANGE FROM

[16 LACSTO_______70 CRORE]

PUNCHCARD_______1959_____________________________________________IN 1959 ALL OPERATINGSYSTEMS ARE DEPENDS ON A PUNCH CARD THAT IS A CHIP WHICH IS FIRST PROGRAMMIZED BEFORE USE THIS TAKE A VERY LONG TIME AND EVEN AFTER THET IT IS NOT SURE THET IT’S WORKING …..

WE CAN SWAP A PUNCH CARD INTO A COMPUETR ONLY ONCE AFTER THAT IT CAN’T BE USED.

AT&T_____AMERICAN TELEGRAPH & TELEPHONY______[MULTICS]________

THIS COMPANY GIVES A NEW OPRATING SYSTEM WHOSE NAME IS MULTICS

THIS IS A SERVER OPRATING SYSTEM WHICH SUPPORTS FOR THE PROPERTIES LIKE MULTITASKING, MULTIUSER, MULTINETWORKING,

MULTICS-_________________________________________________________

IS DEVELOPED IN AMERICA S _____IT BELL LAB_______OR  MIT LAB______

ALL IT SUDIES ARE COMES FROM THESE LABS .

IT BELL___________________________

MIT LABS__MOSTURE INSTITUTE OF TECHNOLOGY.

1960_________KEN THOMPSON________________________________________

KEN THOMPSON IN 1960 WHILE WORKING ON MULTICS FOUND A NEW O/S THAT IS ____________UNIX___________________________________________

UNIX______________________________________________________________

AT THET TIME UNIX IS ONLY SUPPORT FOR THE MULTITASKING OR MULTIUSER IT NOT CONTAINS THE FEATURES OF NETWORING.

ITS PROGRAMMING BASED  ON THE ASSEMBLY LANGUAGE.

1969________DANNIC RITCHHIE_______________________________________

IN 1969 DENNIC RITCHHIE REWRITE THE UNIX AND THEN IT ABLE TO SUPPORT FOR THE NETWORKING ALSO.

HE USE THE LANGUAGE FOR UNIX IS    “C”.

THENNNNNNNNNNNNNNNN

1991___LINUS TORVALDS_____________________________________________

·         Linux was introduced in 1991 by Linus Torvalds, a student at the University of Helsinki, Finland. He worked on the Linux project and wrote the source code for Linux kernel.

·         Linux is available on the internet, so many programmers can add to the code, even changed it, and built in support for all kinds of hardware.

·         Linux is a Unix clone and has been written from scratch by Linus Torvalds. Torvalds was working on Minix : a miniature version of Unix, mainly used as a teaching aid in universities and colleges.

·         Linus Torvalds was impressed with the features of the Unix operating system. So he wanted to create his own version of the Unix operating system and give it freely for use to everybody.

·         Linux is very similar to Unix, Unix was first a single user operating system. In 1969, Ken Thompson, with ideas and help from Dennis Ritchie and others, wrote a small general purpose operating system for small machines.

·         It was liked by number of users, and was eventually developed to be a multi-user operating system

·         LINUX HAVE 1.8 MILLION LINES.

OPEN SOURCE CODE ___________________________________________

LINUX IS A OPEN SOURCE CODE WRITTEN IN SOME LANGUAGE

THIS IS THE COMBINAYION OF THEKERNAL + RESOURCES

                                   

                                    OPEN SOURCE CODE

KERNEL                                                                   RESOURCES         

FOR THE KERNEL DEVELOPMENT THE FOLLOWING LANGUAGES USED.

KEN THOMPSON___________________________ASSEMBLY +”C++”.

DENNIC RITCHHIE__________________________”C” LANGUAGE.

LINUS TORNOLDS__________________________”C” & “C++”.

1…..___RESOURCES______________________________________________

RESOURCES ARE OF TWO TYPES

1__GPL ___GENERAL PACKET LICENCE.IT INSTALLS WITH THE KERNEL AUTOMATICALLY .

2__LGPL__LINUS GENERAL PACKET LICENCE. IT HAS TO BE INSTALLING MANUALLY .

2___KERNEL_____________________________________________________

KERNAL IS THE BASE OF EVERY O/S IN THE WORLD ALL THE RESOURCES ARE INSTALL ON THE KERNAL. SOME OF THE RESOURCES THAT ARE INBUILT IN THE O/S ARE BY DEFAULT ON THE KERNAL .

ANACONDA______IS THE FILE THAT IS NEED TO RUN THE KERNAL AND THIS FILE IS PRESENT IN THE ALL

                                    LOGIN WITHOUT PASSWORD

We normally login as

Login :root

Passwd ----------

]#

But to login without password

[there is a file in a [/etc/passwd] this file conatain all the password informations for all the users. Open the file that contain a [X] follow by the user name like [root:x:0:0: ] simply delete the [X] carefully and it will not ask for the password but when we reassign the password for the user this [x] will come back again to its position.

So by deletion the [X] for the particular user you can loginby that user without enter a password.

Now how to do_________________________________________________________

#vi /etc/passwd

   root:x:0:0:root:/root:/bin:.bash

Delete this x only and the following appears

root::0:0:root:/root:/bin:.bash

:wq! __________ save n exit

Now you can login the root without a password

Login : root

]#

Now if you make more users then to check there entries in the [passwd] file

Press [shift+g] to go to bottom.

SAMBA SERVER :-

                                  To communicate with the Windows system .

# rpm –qa samba *

# cd / etc / samba / smb.conf

# cp smb.conf smb.conf.old

# vi smb.conf

Change in the line number 18  : workgroup = abc

In line number 53 : security = user

Last lines : (xyz)  Path = / root / abc

Writable = Yes

Browsable = Yes , Read only = No

Guest = OK

#useradd abc

#passwd ……

#samba add user root : root

#passwd ……..

#service smb restart

#service network restart

#chk config IP tables off

#test parm (to see the contents of Samba)                                    

~~~~~~~~~~~~~~~~~~~~~~~~~~PERMISSIONS~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

Permissions:- permissions on a user are of two types_______________________________

                                                             Permissions     owner         group   permission           umask

          1_Directory permissions.     |  drwxr-xr-x       root            root            755             0022

          2_File permissions.               |  -rw-r--r--          root            root            644             0022

                                                          A FILE HAVE NOT THE EXECUTE PERMISSIONS BECOUSE WRITE

Read – {4}                                       PERMISSION FOR FILE ACTS AS A EXECUTES PERMISSION.

Write –{2}                       +  = 7    which is the full permission for the file or the directory.  

Execute{1}

         

1_    r:- read permission.       {4}   |for directory       drwxr-xr-x

2_    w:- write permission.    {2}   |

3_    x:- execute permission.{1}    |         this {d} shows that this permission is for directory   

4_     -:_   no permission.      {-}    |for file                -rw-r--r--    this is the permission for file.

Now permission of a file is applied on the {user}, {group} and {other user} they have all different permissions to understand below _________________........

          Take a directory it has 9 digit permission like :--------

Directory                 for Users            for Groups                 for Other users       defaults          permis..

Redhat                 d       rwx                      r-x                                 r-x              per..  7 5 5

                                      421                       421                                421              for     U G O                                                                                                                                       umask0  2  2                                                                                                                                                                       this {d} shows     {7} full permission   {5} read, execute for    {5} read , execute for the other                this is a directory for the users/ owner       all groups                       users which are not member                                                                                                             of any group.

File                                 for Users        for Groups                           for Other users           default permission

server                   {-}      rw-              r--                                         r--           per ..  6 4 4

                                         421             421                                   421         for     G U O    

                                                                                                                       Umask  0 2 2

                                                                                                                                                                                                          At first position {-}   read, write per..    only read for all groups               only read for all other users

            Shows that it’s a file   for users/owner          {{{{ }}}}}}}}}}}}}}}}}}}                                                                  

EXPLAIN  SOME OF HOW THE PERMISSIONS APPLIED ____________________________

                  

            ROOT USER OR                               GROUP USER OR ALL                   OTHER USERS WHO NOT BELONG THE OWNER OF THE FILE             MEMBERS OF THE FROUP                TO ANY GROUP.

G

O

U

                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                 

                rwx                                             rwx                                                   rwx                         for dir..     7rwx                                                5r-x                                                  5r-x                               full per..          7rwx                                       7rwx                                                 7rwx                    

                                                                                                                                                            for file      6rw-                                        4r--                                                   4r--                        full per… 6rw-                                        6rw-                                                  6rw-                                        because file didn’t need execute permission only write or read permission can                             execute the file.

These are the simple permissions for a file or directory by a user for groups and other user

Now how to apply permissions

                   Go to the directory in which directory or file to which permissions are applied then run the commands                       

  Like we have to apply permission on /data file

          # cd /

       /]# chmod 777{ or any of permission u wants} file or dir.. name                        like

       /]# chmod 744 /data

Or

       /]# chmod 644  myfile

OWNERSHIP to give ownership of a file or directory to any other user BY ROOT ONLY

          # chown     pop    [filename]

                            

                                                Username

The user who  makes he file he has the full rights on his file he can do any thing with his file.

And if root write {0} in the permissions at any permissions place. Then user belogs to thet permission even can`t open his own file because {0} refers to no permission 

         

This security of {0} also acts on the groups level security if __0777 then users under group can do nothing.

!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

The default roots id is {0}

Every user has its own primary/private group when we add this into a group then this group is its secondary group. And then this user is member of both of the groups primary  and secondary.

 After add it to secondary group then the group level security is applied on this  that is as _____

THSES PERMISSIONS IMPLIMENTS ONLY ON THE GROUPS AND USERS UNDER GROUPS.

1_ SUID____ Set User Identification.  {4}  

2_ SGID___  Set Group identification {2}

3_STICKBIT _for restriction to delete       {1}

These permissions acts only on the groups and the users under the group its add as a first digit for the permissions  like

To give a user under a group to read permission only on the other members of this group

File is pop

          # chmod     4777  pop