1. Introduction to Unix Operating System
โดย อ.ณัฐกร เฉยศิริ

2. Agenda An Overview of the UNIX Unix Installation Pre Install
Post Install
Startup & Shutdown
Shell & Unix Command
File System
Account Management
Network File System (NFS)
Install Additional Software
Package Management
Install Form Source Code
Process & Job control

3. An Overview of the Unix OS
At first, unix was designed to let a number of programmer
access the same time and share its resource. The important
features that make unix favorite are:
Multitasking
Multiuser
Portability
Unix Tools
Unix Communication
Library of application software

4. Unix Structure
Application Program
Kernel
Hardware

5. Information before install
Size of Memory and Hard Disk
Bandwidth and Memory of Video Card
Mouse type
Host Name
Network information such as IP address, Gateway,Network Address,DNS Server
Time Zone
Root Password

6. Choose Installation Class
Core system support
Contains the minimum software required to boot and run Solaris. but not include the OpenWindows software.
End-user system support
Contains the core system support software plus end user software, which include OpenWindows and the Common Desktop Environment software.
Developer system support
Contains the end-user software plus libraries, include files, man pages, and programming tools for developing software.
Entire distribution.
Contains the entire Solaris 8 release.
Entire distribution plus OEM system support
Contains the entire Solaris 8 release software plus extended
hardware support.

7. Partition Your HDD Single VS Mulitple
Allow finer control over such task as a backup
If one file system corrupted the others remain intact
Allow you control amount of storage for allocate type of use
Easy for manage
All the space on the disk is available for anyone to use

8. Partition Scheme
Root (/)
swap
/usr
/var
/home

9. Post Install Setup Network Connection Install Additional Software
Configure others service such as Printer ,NFS,WWW etc

10. Network Configuration
Display and configure the network interface using the “ifconfig” command
Ensure that the DNS is configured in file /etc/resolv.conf
Ensure that the routing table is set by command “netstat –r”
Ensure that the gateway is set in file /etc/defaultrouter

11. Start up
Before the UNIX operating system can perform correctly, there are a number of steps that must be followed
The failure of any one of these can mean that the system will not start.
It is important for the Systems Administrator to be aware of what happens during system startup so that any problems that occur can be remedied.

12. Booting - consists of the following steps
ROM Phase
Boot Program Phase
Kernel initialization Phase
Init Phase

13. Boot ROM Phase
After turn on power to the system, the ROM will display system identification and run self-test diagnostics to verify system hardware
Then the ROM will loads primary boot program called bootstrap program that store in bootblock of a boot device

14. Boot Program Phase
The boot strap program find and execute the secondary boot program from the file system and load it into memory
After the secondary boot program is loaded, it will load the kernel

15. Kernel initialization Phase
The kernel initializes itself (Create process control and other data structures)
Load device driver modules
Mounts the necessary file system
Create the process 0 (swapper)
Then, bring the system to “initdefault” state specified in /etc/inittab

16. Swapper The first task for the kernel is to start the swapper process.
The swapper process is the part of the kernel that schedules all other process.
The swapper has process ID of 0
It’s first job is to start up the init process

17. Init Phase
The kernel start /sbin/init process, which starts other process by reading the /etc/inittab file
The /sbin/init process start the run control scripts

18. Run Control Script
Each init state has a corresponding series of run control scripts
The init process executes the /sbin/rc<n> script which execute a series of other scripts located in /etc/rc<n>.d directory
All run control scripts are also located in the /etc/init.d directory. These file are linked to run control scripts in /etc/rc<n>.d directory

19. Run Level Run level Description Halt the machine 1
Halt the machine 1
Single user mode. All file systems mounted,
only small set of kernel processes running.
only root can login. 2
multi-user mode , without remote file sharing 3
multi-user mode with remote file sharing,
processes, and daemons 4
undefine 5
used for to start X11 on boot 6
shutdown and reboot
s or S
same as single-user mode

20. Shutdown A UNIX machine should (almost) never be just turned off.
It is also important for the Systems Administrator to understand what the correct mechanism is to shut a UNIX machine down
There are a number of steps to carry out to ensure that the operating system and many of its support functions remain in a consistent state.

21. Step before shutdown Commands to shut down
List of all logged-in user by “who” command.
You might sent broadcast message to let user know the system being shutdown
Flush file system buffer to physical disk by “sync”
Use Shut Down command
Commands to shut down
/usr/sbin/shutdown
/sbin/init
/usr/sbin/halt
/usr/sbin/reboot

22. Unix Shell Unix is a layered operating system.
The OS not allow applications accessing the hardware directly.
The shell acts as a command interpreter.
It takes each command and passes it to the operating system kernel to be acted upon. And then displays the results of this operation

23. Relationship for Kernel,Shell and Application

24. Features provided by the shell
The shell provides you with one or more of the following features.

25. Types of shell
There are several different shells available for Unix. The most popular are described here.
Bourne shell (sh)
C shell (csh)
Korn shell (ksh)
Bourne Again Shell (bash)

26. Unix Command
A command is a program that tells the Unix system to do something.
Usually has the form: command [options] [arguments]
Commands are case sensitive. command and Command are not the same.
Options and syntax for a command are listed in the man page

27. Navigation and Directory Control Commands

28. File Maintenance Commands

29. Miscellaneous commands

30. Unix file type
Regular file. A common file which contains data in text or binary.
Directory file. A file that contains name of other files and point to information on these files.
Symbolic link. A type of file that point to another file.

31. Unix file type
Character devices file. A type of file use for certain type of devices(read-write data in one character).
Block devices file. A type of file use for certain type of devices(read-write data in block).
FIFO. A type of file that use for interprocess communication,some time call named pipe.
Socket. A type of file that use for network communication.

32. Regular File
A regular file simply holds data. Perhaps the most common file type found in the Solaris Operating Environment are regular files, which allow you to store many different kinds of data. Regular files can hold ASCII text, binary data, image data, databases, application-related data, and more.

33. Directory file
Directories store information that associates file names with inode numbers. Unlike regular files that can hold many different kinds of data, directories can hold only one kind.

34. Symbolic link
A symbolic link is a file that points to another file. Like directories,
symbolic links contain only one kind of data. A symbolic link contains the pathname of the file to which it points.

35. File type & symbol Type Symbol Regular file - Directory d
Character device c
Block device b
Unix domain socket s
Name pipes p
link file l

36. File Access Permission
Symbol
Permission
Means r
Read
Can open and read content of file w
Write
Can write to file(Modify content)
or delete it x
Execute
Can execute the file(if it program
or shell script) -
Denied
Cannot read, write or execute file

37. Group Type Owner Others - r w x - - x r - x d r w x r - x r - -
Example 1
Example 2 d
r w x
r - x
r - -

38. The following example shows the use of the ls –la command to display permission file

39. Permission and Owner Command
chmod [–R] permission filename
Changes access permission of a file.
chown [-R] username:groupname filename
Changes the ownership of a file.
chgrp [-R] groupid filename
Changes the group ownership of a file.

40. Account Management Every user on a UNIX machine must have an account.
Components of a user account are:
login name (also called a username).
password.
The numeric user identifier or UID.
The numeric group identifier or GID.
home directory.
login shell.
startup files.

41. Add use from GUI tools

42. Configuration files related to user accounts
/etc/passwd the password file, holds most of an account characteristics including username, UID, GID,GCOS information, login shell, home directory
/etc/shadow the shadow password file, a more secure mechanism for holding the password
/etc/group the group file, holds characteristics about a system's groups including group name, GID and group members

43. Fields in /etc/passwd file
Each line in the /etc/passwd file contains several fields, separated by a colon ( : ) , and is formatted as follows:
username:password:uid:gid:comment:
home-directory:loginshell

44. Fields in /etc/shadow file
Each line in the /etc/shadow file contains several fields, separated by a colon ( : ) , and is formatted as follows:
username:password:lastchange:min:max:
warn:inactive:expire

45. Startup Files
Once the home directory is created the startup files can be copied in or created. Again you should remember that this will be done as the root user and so root will own the files. You must remember to change the ownership.
For example
The following is example set of commands that will perform
these tasks.
mkdir home_directory
cp -pr /etc/skel/.* home_directory
chown -R login_name home_directory
chgrp -R group_name home_directory
chmod -R 700 home_directory

46. The NFS Distributed File System
The NFS environment contains the following components:
NFS server – A system that contains the file resources to be shared with other systems on the network.
NFS client – A system that mounts the file resources shared over the network and presents the file resources as if they were local.

47. Configuring the NFS File Server
To set up an NFS server, complete the following steps:
Edit the /etc/dfs/dfstab file and add those file resources to be
automatically shared whenever the system enters run level 3. For example:
# share -F nfs /usr/share/man
2. Start the NFS server daemons by invoking the following:
# /etc/init.d/nfs.server start
This shares the contents of the /etc/dfs/dfstab file.

48. The NFS Client Setup
1. Use the /usr/sbin/dfshares command to display a server’s available resources.
# dfshares host1
2. Use the /usr/sbin/mount command to access the remote file resource.
# mount host1:/usr/share/man /usr/share/man
3. To unmount the remote file resources from the client by using the /usr/sbin/umount command.
# umount /usr/share/man

49. Install Software Using Package Management
pkginfo command to display information about the software packages that have been installed
pkgadd command uncompresses and copies files from the installation media to the local system’s disk.
pkgrm command deletes all files associated with that package unless those files are also shared with other packages.

50. Install Software From Source Code
Tool & Utility for Compile Source code
Compiler & Library (GNUgcc & libgcc)
Make (GNUmake)
Autoconfigure (GNUautoconfigure)
Compress/Uncompress (gzip/gunzip/tar)

51. Apache Web Server Install
Overview for install apache
$ ./configure --prefix=PREFIX
$ make
$ make install
NOTE: PREFIX by default use
"/usr/local/apache"

52. Configuration File
Finally you can customize your Apache HTTP server by editing the configuration files
$ vi PREFIX/conf/httpd.conf
$ vi PREFIX/conf/access.conf
$ vi PREFIX/conf/srm.conf
And Statrt web server by
$PREFIX/bin/apachectl start

53. Most Important Configure
ServerName avalon.bu.ac.th
ServerAdmin
DocumentRoot "/usr/local/apache/htdocs"
*Note ServerRoot and DocumentRoot is difference meaning

54. Process & Job control
A Unix process is an instance of an executing program It has a separate existence from all the other processes on the system we say that each process has its own address space
A unique number known as its process-id or pid
The pid of its parent process is the process which started it, usually a shell

55. Process state Processes also have state
One a single-CPU machine, only one
process is running
Most processes are sleeping, waiting for
input or output to finish
There are a few other odd states: swapped,
zombie, or stopped.

56. Job control
The mechanism that shuffle processes from foreground, background and stopped is known as job control
Job control requires three condition for support
A shell that support job control.
The terminal driver in the kernel must support job control
Support for certain job-control signals must be provided.

57. Foreground and Background Tasks
Unix allows running processes to be disconnected from their terminals
Unix has the concept of foreground processes which are attached to a user's terminal
background processes, which have no terminal to read from

58. Job control & process management command
ps report process status
kill terminate or signal processes
Control process execution
jobs report job status
bg bring job to background process
fg bring job to foreground process
stop stop the job

59. Signals Signals are a technique used to notify a process that
some condition has occurred.
Ordinary users can only send signals to their
own processes.
The command to send signal to process is “kill”.
example:
$ kill -signal processid

60. Here are some examples:
$ sleep # Wait for 100 seconds, then go back to shell
ctrl-C # Kill sleep process
$ sleep 100 & # Wait for 100 seconds in the background
$ jobs # Show list of jobs
[1] + Running sleep 100 &
$ kill SIGSTOP % # Stop sleep process (job number 1)
$ jobs
[1] + Stopped (SIGSTOP) sleep 100 &
$ bg % # Put sleep in background
$ fg % # Bring sleep in foreground, reattached
# to the terminal