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LINUX SYSTEM Presentation Transcript
1.Introduction to LINUX SYSTEM
2.UNIX
Unix is a multi-user, multi-tasking operating system.
You can have many users logged into a system simultaneously, each running many programs.
It's the kernel's job to keep each process and user separate and to regulate access to system hardware, including cpu, memory, disk and other I/O devices.
Unix is a multi-user, multi-tasking operating system.
You can have many users logged into a system simultaneously, each running many programs.
It's the kernel's job to keep each process and user separate and to regulate access to system hardware, including cpu, memory, disk and other I/O devices.
3.History of UNIX
First Version was created in Bell Labs in 1969.
Some of the Bell Labs programmers who had worked on this project, Ken Thompson, Dennis Ritchie, Rudd Canaday, and Doug McIlroy designed and implemented the first version of the Unix File System on a PDP-7 along with a few utilities. It was given the name UNIX by Brian Kernighan.
00:00:00 Hours, Jan 1, 1970 is time zero for UNIX. It is also called as epoch.
First Version was created in Bell Labs in 1969.
Some of the Bell Labs programmers who had worked on this project, Ken Thompson, Dennis Ritchie, Rudd Canaday, and Doug McIlroy designed and implemented the first version of the Unix File System on a PDP-7 along with a few utilities. It was given the name UNIX by Brian Kernighan.
00:00:00 Hours, Jan 1, 1970 is time zero for UNIX. It is also called as epoch.
4.1973 Unix is re-written mostly in C, a new language developed by Dennis Ritchie.
Being written in this high-level language greatly decreased the effort needed to port it to new machines.
Being written in this high-level language greatly decreased the effort needed to port it to new machines.
5.1977 There were about 500 Unix sites world-wide.
1980 BSD 4.1 (Berkeley Software Development)
1983 SunOS, BSD 4.2, System V
1988 AT&T and Sun Microsystems jointly develop System V Release 4 (SVR4). This later developed into UnixWare and Solaris 2.
1991 Linux was originated.
1980 BSD 4.1 (Berkeley Software Development)
1983 SunOS, BSD 4.2, System V
1988 AT&T and Sun Microsystems jointly develop System V Release 4 (SVR4). This later developed into UnixWare and Solaris 2.
1991 Linux was originated.
6.Linux is a free Unix-type operating system originally created by Linus Torvalds with the assistance of developers around the world.
It originated in 1991 as a personal project of Linus Torvalds, a Finnish graduate student.
The Kernel version 1.0 was released in 1994 and today the most recent stable version is 2.6.9
Developed under the GNU General Public License , the source code for Linux is freely available to everyone.
It originated in 1991 as a personal project of Linus Torvalds, a Finnish graduate student.
The Kernel version 1.0 was released in 1994 and today the most recent stable version is 2.6.9
Developed under the GNU General Public License , the source code for Linux is freely available to everyone.
7.What is Linux?
A fully-networked Unix-like Operating System
Unix Tools Like sed, awk, and grep
Compilers Like C, C++, Fortran, Smalltalk, Ada
Network Tools Like telnet, ftp, ping, traceroute
Multi-user, Multitasking, Multiprocessor
Has the similar Windows GUI
Coexists with other Operating Systems
Runs on multiple platforms
Includes the Source Code
8.Where did it come from?
Linus Torvalds created it
with assistance from programmers around the world
first posted on Internet in 1991
Linux 1.0 in 1994; 2.2 in 1999
Today used on 7-10 million computers
with 1000’s of programmers working to enhance it
9.LINUX Distributions
Mandrake: http://www.mandrakesoft.com/
RedHat: http://www.redhat.com/
Fedora: http://fedora.redhat.com/
SuSE/Novell: http://www.suse.com/
Debian: http://www.debian.org/
Red Hat Enterprise Linux is a Enterprise targeted Operating System. It based on mature Open Source technology and available at a cost with one year Red Hat Network subscription for upgrade and support contract.
A fully-networked Unix-like Operating System
Unix Tools Like sed, awk, and grep
Compilers Like C, C++, Fortran, Smalltalk, Ada
Network Tools Like telnet, ftp, ping, traceroute
Multi-user, Multitasking, Multiprocessor
Has the similar Windows GUI
Coexists with other Operating Systems
Runs on multiple platforms
Includes the Source Code
8.Where did it come from?
Linus Torvalds created it
with assistance from programmers around the world
first posted on Internet in 1991
Linux 1.0 in 1994; 2.2 in 1999
Today used on 7-10 million computers
with 1000’s of programmers working to enhance it
9.LINUX Distributions
Mandrake: http://www.mandrakesoft.com/
RedHat: http://www.redhat.com/
Fedora: http://fedora.redhat.com/
SuSE/Novell: http://www.suse.com/
Debian: http://www.debian.org/
Red Hat Enterprise Linux is a Enterprise targeted Operating System. It based on mature Open Source technology and available at a cost with one year Red Hat Network subscription for upgrade and support contract.
10.File System
Each node is either a file or a directory of files, where the latter can contain other files and directories.
You specify a file or directory by its path name, either the full, or absolute, path name or the one relative to a location.
The full path name starts with the root, /, and follows the branches of the file system, each separated by /, until you reach the desired file, e.g.:
/home/condron/source/xntp
11.A relative path name specifies the path relative to another, usually the current working directory that you are at. Two special directories :
. the current directory
.. the parent of the current directory
So if I'm at /home/frank and wish to specify the path above in a relative fashion I could use:
../condron/source/xntp
This indicates that I should first go up one directory level, then come down through the condron directory, followed by the source directory and then to xntp.
12.Structure of Standard Directories in Unix/Linux
/ The ancestor of all directories on the system; all other directories are subdirectories of this directory, either directly or through other subdirectories.
/bin Essential tools and other programs (or binaries).
/dev Files representing the system's various hardware devices. For example, you use the file `/dev/cdrom' to access the CD-ROM drive.
/etc Miscellaneous system configuration files, startup files, etc.
13.Structure of Standard Directories in Unix/Linux
Each node is either a file or a directory of files, where the latter can contain other files and directories.
You specify a file or directory by its path name, either the full, or absolute, path name or the one relative to a location.
The full path name starts with the root, /, and follows the branches of the file system, each separated by /, until you reach the desired file, e.g.:
/home/condron/source/xntp
11.A relative path name specifies the path relative to another, usually the current working directory that you are at. Two special directories :
. the current directory
.. the parent of the current directory
So if I'm at /home/frank and wish to specify the path above in a relative fashion I could use:
../condron/source/xntp
This indicates that I should first go up one directory level, then come down through the condron directory, followed by the source directory and then to xntp.
12.Structure of Standard Directories in Unix/Linux
/ The ancestor of all directories on the system; all other directories are subdirectories of this directory, either directly or through other subdirectories.
/bin Essential tools and other programs (or binaries).
/dev Files representing the system's various hardware devices. For example, you use the file `/dev/cdrom' to access the CD-ROM drive.
/etc Miscellaneous system configuration files, startup files, etc.
13.Structure of Standard Directories in Unix/Linux
14./sbin Essential system administrator tools, or system binaries.
/tmp Temporary files.
/usr Subdirectories with files related to user tools and applications.
15.Directories, Files and Inodes
Every directory and file is listed in its parent directory.
In the case of the root directory, that parent is itself.
A directory is a file that contains a table listing the files contained within it, giving file names to the inode numbers in the list.
The information about all the files and directories is maintained in INODE TABLE
An Inode (Index Nodes) is an entry in the table containing information about a file (metadata) including file permissions, UID, GID, size, time stamp, pointers to files data blocks on the disk etc.
/tmp Temporary files.
/usr Subdirectories with files related to user tools and applications.
15.Directories, Files and Inodes
Every directory and file is listed in its parent directory.
In the case of the root directory, that parent is itself.
A directory is a file that contains a table listing the files contained within it, giving file names to the inode numbers in the list.
The information about all the files and directories is maintained in INODE TABLE
An Inode (Index Nodes) is an entry in the table containing information about a file (metadata) including file permissions, UID, GID, size, time stamp, pointers to files data blocks on the disk etc.
16.Logging In
Connect to the Linux system using telnet:
vt100, vt220, vt320
ansi
tty
X-windows
Able to login more than once with same user
No ‘MW’ problems!
Connect to the Linux system using telnet:
vt100, vt220, vt320
ansi
tty
X-windows
Able to login more than once with same user
No ‘MW’ problems!
17.Logging In
Linux 2.2.13 (penguinvm.princeton.edu) (ttyp1)
penguinvm login: neale
Password:
Last login: Tue Jan 4 10:13:13 from linuxtcp.princeton.edu
[neale@penguinvm neale]$
Linux 2.2.13 (penguinvm.princeton.edu) (ttyp1)
penguinvm login: neale
Password:
Last login: Tue Jan 4 10:13:13 from linuxtcp.princeton.edu
[neale@penguinvm neale]$
18.Rule Number 1
19.Creating a new user
Use the useradd command
Use the passwd command to set password
Try it… logon as root
Use the useradd command
Use the passwd command to set password
Try it… logon as root
20.Adding a new user
Limits on users can be controlled by
Quotas
ulimit command
Authority levels for a user controlled by group membership
Limits on users can be controlled by
Quotas
ulimit command
Authority levels for a user controlled by group membership
21.Users and Groups
Users are identified by user identifications (UIDs), each of which is associated with an integer in the range of 0 to 4 294 967 295 (X’FFFFFFFF’). Users with UID=0 are given superuser privileges.
Users are placed in groups, identified by group identifications (GIDs). Each GID is associated with an integer in the range from 0 to 4 294 967 295
Let the system assign UID to avoid duplicates
Use id to display your user and group information
Users are identified by user identifications (UIDs), each of which is associated with an integer in the range of 0 to 4 294 967 295 (X’FFFFFFFF’). Users with UID=0 are given superuser privileges.
Users are placed in groups, identified by group identifications (GIDs). Each GID is associated with an integer in the range from 0 to 4 294 967 295
Let the system assign UID to avoid duplicates
Use id to display your user and group information
22.Groups define functional areas/responsibilities
They allow a collection of users to share files
A user can belong to multiple groups
You can see what groups you belong to using the groups command:
They allow a collection of users to share files
A user can belong to multiple groups
You can see what groups you belong to using the groups command:
23.Typical Group Setup
24.Using the new user
Now logoff using the exit command
login as the new user
Now logoff using the exit command
login as the new user
25.You need help?
The Linux equivalent of HELP is man (manual)
Use man -k <keyword> to find all commands with that keyword
Use man <command> to display help for that command
Output is presented a page at a time. Use b for to scroll backward, f or a space to scroll forward and q to quit
The Linux equivalent of HELP is man (manual)
Use man -k <keyword> to find all commands with that keyword
Use man <command> to display help for that command
Output is presented a page at a time. Use b for to scroll backward, f or a space to scroll forward and q to quit
26.The Linux System
27.Naming Files
28.The Current Directory
29.Some Special File Names
Some file names are special:
/ The root directory (not to be confused with the root user)
. The current directory
.. The parent (previous) directory
~ My home directory
Some file names are special:
/ The root directory (not to be confused with the root user)
. The current directory
.. The parent (previous) directory
~ My home directory
30.Special Files
/home - all users’ home directories are stored here
/bin, /usr/bin - system commands
/sbin, /usr/sbin - commands used by sysadmins
/etc - all sorts of configuration files
/var - logs, spool directories etc.
/dev - device files
/proc - special system files
/home - all users’ home directories are stored here
/bin, /usr/bin - system commands
/sbin, /usr/sbin - commands used by sysadmins
/etc - all sorts of configuration files
/var - logs, spool directories etc.
/dev - device files
/proc - special system files
31.Linux Command Basics
32.Standard Files
UNIX concept of “standard files”
standard input (where a command gets its input) - default is the terminal
standard output (where a command writes it output) - default is the terminal
standard error (where a command writes error messages) - default is the terminal
UNIX concept of “standard files”
standard input (where a command gets its input) - default is the terminal
standard output (where a command writes it output) - default is the terminal
standard error (where a command writes error messages) - default is the terminal
33.Redirecting Output
34.The input of a command may come (be piped) from a file:
35.Connecting commands with Pipes
36.Command Options
37.Common Commands
38.File Commands
cp <fromfile> <tofile>
Copy from the <fromfile> to the <tofile>
mv <fromfile> <tofile>
Move/rename the <fromfile> to the <tofile>
rm <file>
Remove the file named <file>
mkdir <newdir>
Make a new directory called <newdir>
rmdir <dir>
Remove an (empty) directory
cp <fromfile> <tofile>
Copy from the <fromfile> to the <tofile>
mv <fromfile> <tofile>
Move/rename the <fromfile> to the <tofile>
rm <file>
Remove the file named <file>
mkdir <newdir>
Make a new directory called <newdir>
rmdir <dir>
Remove an (empty) directory
39.More Commands
who
List who is currently logged on to the system
whoami
Report what user you are logged on as
ps
List your processes on the system
ps aux
List all the processes on the system
echo “A string to be echoed”
Echo a string (or list of arguments) to the terminal
who
List who is currently logged on to the system
whoami
Report what user you are logged on as
ps
List your processes on the system
ps aux
List all the processes on the system
echo “A string to be echoed”
Echo a string (or list of arguments) to the terminal
40.Shells
An interface between the Linux system and the user
Used to call commands and programs
An interpreter
Powerful programming language
“Shell scripts” = .bat .cmd EXEC REXX
Many available (bsh; ksh; csh; bash; tcsh)
An interface between the Linux system and the user
Used to call commands and programs
An interpreter
Powerful programming language
“Shell scripts” = .bat .cmd EXEC REXX
Many available (bsh; ksh; csh; bash; tcsh)
41.Another definition of a Shell
A shell is any program that takes input from the user, translates it into instructions that the operating system can understand, and conveys the operating system's output back to the user.
i.e. Any User Interface
Character Based v Graphics Based
A shell is any program that takes input from the user, translates it into instructions that the operating system can understand, and conveys the operating system's output back to the user.
i.e. Any User Interface
Character Based v Graphics Based
42.Why Do I Care About The Shell?
Shell is Not Integral Part of OS
UNIX Among First to Separate
Compare to MS-DOS, Mac, Win95, VM/CMS
GUI is NOT Required
Default Shell Can Be Configured
chsh -s /bin/bash
/etc/passwd
Helps To Customize Environment
Shell is Not Integral Part of OS
UNIX Among First to Separate
Compare to MS-DOS, Mac, Win95, VM/CMS
GUI is NOT Required
Default Shell Can Be Configured
chsh -s /bin/bash
/etc/passwd
Helps To Customize Environment
43.Shell Scripts
44.Switching Users
su <accountname>
switch user accounts. You will be prompted for a password. When this command completes, you will be logged into the new account. Type exit to return to the previous account
su
Switch to the root user account. Do not do this lightly
Note: The root user does not need to enter a password when switching users. It may become any user desired. This is part of the power of the root account.
su <accountname>
switch user accounts. You will be prompted for a password. When this command completes, you will be logged into the new account. Type exit to return to the previous account
su
Switch to the root user account. Do not do this lightly
Note: The root user does not need to enter a password when switching users. It may become any user desired. This is part of the power of the root account.
45.Environment Variables
Environment variables are global settings that control the function of the shell and other Linux programs. They are sometimes referred to global shell variables.
Environment variables are global settings that control the function of the shell and other Linux programs. They are sometimes referred to global shell variables.
46.Some Important Environment Variables
HOME
Your home directory (often be abbreviated as “~”)
TERM
The type of terminal you are running (for example vt100, xterm, and ansi)
PWD
Current working directory
PATH
List of directories to search for commands
HOME
Your home directory (often be abbreviated as “~”)
TERM
The type of terminal you are running (for example vt100, xterm, and ansi)
PWD
Current working directory
PATH
List of directories to search for commands
47.PATH Environment Variable
Controls where commands are found
PATH is a list of directory pathnames separated by colons. For example:
PATH=/bin:/usr/bin:/usr/X11R6/bin:/usr/local/bin:/home/scully/bin
If a command does not contain a slash, the shell tries finding the command in each directory in PATH. The first match is the command that will run
Controls where commands are found
PATH is a list of directory pathnames separated by colons. For example:
PATH=/bin:/usr/bin:/usr/X11R6/bin:/usr/local/bin:/home/scully/bin
If a command does not contain a slash, the shell tries finding the command in each directory in PATH. The first match is the command that will run
48.PATH Environment Variable
Similar to setting the CMS search order
Usually set in /etc/profile (like the SYSPROF EXEC)
Often modified in ~/.profile (like the PROFILE EXEC)
Similar to setting the CMS search order
Usually set in /etc/profile (like the SYSPROF EXEC)
Often modified in ~/.profile (like the PROFILE EXEC)
49.File Permissions
Every file
Is owned by someone
Belongs to a group
Has certain access permissions for owner, group, and others
Default permissions determined by umask
Every file
Is owned by someone
Belongs to a group
Has certain access permissions for owner, group, and others
Default permissions determined by umask
50.File Permissions
The long version of a file listing (ls -l) will display the file permissions:
The long version of a file listing (ls -l) will display the file permissions:
51.Interpreting File Permissions
52.Changing File Permissions
53.Links?
Links are references to files (aliases)
Two forms:
Hard
Symbolic
Can point to files on different physical devices
Delete of original leaves link
Delete of link leaves original
Can be created for directories
Create using ln command
Links are references to files (aliases)
Two forms:
Hard
Symbolic
Can point to files on different physical devices
Delete of original leaves link
Delete of link leaves original
Can be created for directories
Create using ln command
54.Editors
People are fanatical about their editor
Several choices available:
vi Standard UNIX editor
the XEDIT-like editor
xedit X windows text editor
emacs Extensible, Customizable Self- Documenting Display Editor
pico Simple display-oriented text editor
nedit X windows Motif text editor
People are fanatical about their editor
Several choices available:
vi Standard UNIX editor
the XEDIT-like editor
xedit X windows text editor
emacs Extensible, Customizable Self- Documenting Display Editor
pico Simple display-oriented text editor
nedit X windows Motif text editor
55.Linux Device Handling
56.Devices and Drivers
57.Special Files - /proc
58.File Systems
Linux supports many different types
Most commonly, ext2fs
Filenames of 255 characters
File sizes up to 2GB
Theoretical limit 4TB
Derived from extfs
Highly reliable and high performer
Linux supports many different types
Most commonly, ext2fs
Filenames of 255 characters
File sizes up to 2GB
Theoretical limit 4TB
Derived from extfs
Highly reliable and high performer
59.Virtual File System
VFS is designed to present a consistent view of data as stored on hardware
Almost all hardware devices are represented using a generic interface
VFS goes further, allowing the sysadmin to mount any of a set of logical file systems on any physical device
VFS is designed to present a consistent view of data as stored on hardware
Almost all hardware devices are represented using a generic interface
VFS goes further, allowing the sysadmin to mount any of a set of logical file systems on any physical device
60.Virtual File System
Logical file systems promote compatibility with other operating system standards permitting developers to implement file systems with different policies
VFS abstracts details of physical device and logical file system allowing processes to access files using a common interface, without knowing what physical or logical system the file resides on
Logical file systems promote compatibility with other operating system standards permitting developers to implement file systems with different policies
VFS abstracts details of physical device and logical file system allowing processes to access files using a common interface, without knowing what physical or logical system the file resides on
61.Analogous to CMS:
SFS
Minidisks
Two different designs
Common/transparent access
SFS
Minidisks
Two different designs
Common/transparent access
62.Processes
Processes are created in a hierarchical structure whose depth is limited only by the virtual memory available to the virtual machine
A process may control the execution of any of its descendants by suspending or resuming it, altering its relative priority, or even terminating it
Termination of a process by default causes termination of all its descendants; termination of the root process causes termination of the session
Linux assigns a process ID (PID) to the process
Processes are created in a hierarchical structure whose depth is limited only by the virtual memory available to the virtual machine
A process may control the execution of any of its descendants by suspending or resuming it, altering its relative priority, or even terminating it
Termination of a process by default causes termination of all its descendants; termination of the root process causes termination of the session
Linux assigns a process ID (PID) to the process
63.Daemons
Background processes for system administration are referred to as “daemons”
These processes are usually started during the boot process
The processes are not assigned any terminals
Background processes for system administration are referred to as “daemons”
These processes are usually started during the boot process
The processes are not assigned any terminals
64.Processes - UID & GID
65.Effective UID
The effective UID is used to determine owner access privileges of a process.
Normally the same as the real UID. It is possible for a program to have a special flag set that, when this program is executed, changes the effective UID of the process to the UID of the owner of the program.
A program with this special flag set is said to be a set-user-ID program (SUID). This feature provides additional permissions to users while the SUID program is being executed.
The effective UID is used to determine owner access privileges of a process.
Normally the same as the real UID. It is possible for a program to have a special flag set that, when this program is executed, changes the effective UID of the process to the UID of the owner of the program.
A program with this special flag set is said to be a set-user-ID program (SUID). This feature provides additional permissions to users while the SUID program is being executed.
66.Effective GID
Each process also has an effective group
The effective GID is used to determine group access privileges of a process
Normally the same as the real GID. A program can have a special flag set that, when this program is executed, changes the effective GID of the process to the GID of the owner of this program
A program with this special flag set is said to be a set-group-ID program (SGID). Like the SUID feature, this provides additional permission to users while the set-group-ID program is being executed
Each process also has an effective group
The effective GID is used to determine group access privileges of a process
Normally the same as the real GID. A program can have a special flag set that, when this program is executed, changes the effective GID of the process to the GID of the owner of this program
A program with this special flag set is said to be a set-group-ID program (SGID). Like the SUID feature, this provides additional permission to users while the set-group-ID program is being executed
67.Processes - Process Groups
Each process belongs to a process group
A process group is a collection of one or more processes
Each process group has a unique process group ID
It is possible to send a signal to every process in the group just by sending the signal to the process group leader
Each time the shell creates a process to run an application, the process is placed into a new process group
When an application spawns new processes, these are members of the same process group as the parent
Each process belongs to a process group
A process group is a collection of one or more processes
Each process group has a unique process group ID
It is possible to send a signal to every process in the group just by sending the signal to the process group leader
Each time the shell creates a process to run an application, the process is placed into a new process group
When an application spawns new processes, these are members of the same process group as the parent
68.Processes - PID
PID
A process ID is a unique identifier assigned to a process while it runs
Each time you run a process, it has a different PID (it takes a long time for a PID to be reused by the system)
You can use the PID to track the status of a process with the ps command or the jobs command, or to end a process with the kill command
PID
A process ID is a unique identifier assigned to a process while it runs
Each time you run a process, it has a different PID (it takes a long time for a PID to be reused by the system)
You can use the PID to track the status of a process with the ps command or the jobs command, or to end a process with the kill command
69.Security Guidelines
Take Care With Passwords
Use good ones (motherhood statement)
Don't Use Real Words
Make Sure They Are Not Easily Guessed
Use Combinations Of Upper and Lower Case, Numbers, Punctuation
One Method: Take first letter of a sentence or book title, insert numbers and punctuation.
Take Care With Passwords
Use good ones (motherhood statement)
Don't Use Real Words
Make Sure They Are Not Easily Guessed
Use Combinations Of Upper and Lower Case, Numbers, Punctuation
One Method: Take first letter of a sentence or book title, insert numbers and punctuation.
70.Security - Important Files
71.Linux/390 Specifics
An ASCII implementation
Adds a layer of abstraction to I/O
Channel based v IRQ based
Support for ECKD using SSCH
Support for VM minidisks (ECKD, CKD, FBA, VDISK)
An ASCII implementation
Adds a layer of abstraction to I/O
Channel based v IRQ based
Support for ECKD using SSCH
Support for VM minidisks (ECKD, CKD, FBA, VDISK)
72.Linux/390 Specifics
Runs natively, in LPAR, or under VM/ESA
Uses relative instructions: G2, P/390, R/390 or better
Will use hardware IEEE FP or will emulate
Network drivers for CTCA/ESCON, OSA-2, and IUCV (VM only)
3215 emulation for virtual console
Hardware console driver (HMC)
Runs natively, in LPAR, or under VM/ESA
Uses relative instructions: G2, P/390, R/390 or better
Will use hardware IEEE FP or will emulate
Network drivers for CTCA/ESCON, OSA-2, and IUCV (VM only)
3215 emulation for virtual console
Hardware console driver (HMC)
73.Linux/390 Specifics
GNU tools ported
C/C++ compiler (gcc-2.95.1)
Assembler and linker (binutils-2.9.1)
Packages “ported”:
Regina; THE; UFT; X11; OpenLDAP; IMAP; Sendmail; Bind; RPM; Samba 2.0.6; Apache; Perl
GNU tools ported
C/C++ compiler (gcc-2.95.1)
Assembler and linker (binutils-2.9.1)
Packages “ported”:
Regina; THE; UFT; X11; OpenLDAP; IMAP; Sendmail; Bind; RPM; Samba 2.0.6; Apache; Perl
74.Linux in the Business World
75.Linux’s place in the market
The business world is interested in:
Efficiency and effectiveness
Networked economy
Network-based businesses
The business world is interested in:
Efficiency and effectiveness
Networked economy
Network-based businesses
76.Linux’s place in the market
77.Linux’s place in the market
Importance of the application model
Server-centric and based on standards that span multiple platforms
Leverage core business systems and scale to meet unpredictable demands
Quick to deploy, easy to use and manage
Importance of the application model
Server-centric and based on standards that span multiple platforms
Leverage core business systems and scale to meet unpredictable demands
Quick to deploy, easy to use and manage
78.ISVs which have made Linux announcements:
BEA; Novell; SAP; Informix; Oracle, IBM; HP; CA; ApplixWare; Star; Corel; Cygnus; MetroWerks; ObjectShare; Inprise
Media spotlight:
CNN; PCWorld; PCWeek; InternetWeek
BEA; Novell; SAP; Informix; Oracle, IBM; HP; CA; ApplixWare; Star; Corel; Cygnus; MetroWerks; ObjectShare; Inprise
Media spotlight:
CNN; PCWorld; PCWeek; InternetWeek
79.Early commercial users
Cendant Corporation - 4000 hotels
Burlington Coat Factory - back office functions
Northwest Airlines - 23 flight simulators
Intel announcement January 5 2000
New web appliances to run Linux
At the insistence of customers (e.g. NEC)
Cendant Corporation - 4000 hotels
Burlington Coat Factory - back office functions
Northwest Airlines - 23 flight simulators
Intel announcement January 5 2000
New web appliances to run Linux
At the insistence of customers (e.g. NEC)
80.Impacts:
Applications:
Webservers (65%)
WebInfrastructure (mail, DNS) (15%)
File/Print (15%)
DB & DB Applications (2%)
Observations
Linux/Apache share of Web serving high
Autonomous departments
Many SMB and small ISP
CIOs discovering they have Linux running somewhere
Strong mindshare among developers
Applications:
Webservers (65%)
WebInfrastructure (mail, DNS) (15%)
File/Print (15%)
DB & DB Applications (2%)
Observations
Linux/Apache share of Web serving high
Autonomous departments
Many SMB and small ISP
CIOs discovering they have Linux running somewhere
Strong mindshare among developers
81.Linux’s place in the market
Linux’s appeal
Embraces new generation of web-based apps
Player in the heterogeneous e-business world
Provides flexibility and choice of environment
Open Source focuses on open standards
Linux’s appeal
Embraces new generation of web-based apps
Player in the heterogeneous e-business world
Provides flexibility and choice of environment
Open Source focuses on open standards
82.Linux’s place in the market
Challenges for growth
Products/Technologies/Offerings
Support services
ISV applications
Service providers
Trends
Movement to mainstream
Standards
Ease of use
Challenges for growth
Products/Technologies/Offerings
Support services
ISV applications
Service providers
Trends
Movement to mainstream
Standards
Ease of use
83.Website Development
ASWedit, HTML editor
Empress DataWEB
EZ-EDIT
LinkScan
TalentSoft Web+ (WebPlus)
ASWedit, HTML editor
Empress DataWEB
EZ-EDIT
LinkScan
TalentSoft Web+ (WebPlus)
84.Databases
85.Data Visualization and CAD
IDL (Interactive Data Language)
Megahedron
Tecplot 7.0
VariCAD
VARKON
XVScan
IDL (Interactive Data Language)
Megahedron
Tecplot 7.0
VariCAD
VARKON
XVScan
86.Development Tools
87.Emulation Tools
Emulus
Executor 2
Wabi 2.2 for OpenLinux
Emulus
Executor 2
Wabi 2.2 for OpenLinux
88.Financial Software
BB Stock Pro and BB Stock Tool
TimeClock
BB Stock Pro and BB Stock Tool
TimeClock
89.Libraries
FontScope
INTERACTER
Matrix<LIB> - C++ Math Matrix Library
PKWARE Data Compression Library for Linux
readyBase
SIMLIB IG
FontScope
INTERACTER
Matrix<LIB> - C++ Math Matrix Library
PKWARE Data Compression Library for Linux
readyBase
SIMLIB IG
90.Mathematics
Maple V Release 4 - The Power Edition
MATCOM and MATCOM MATH LIBRARY
Mathematica 3.0
MATLAB and Simulink
Maple V Release 4 - The Power Edition
MATCOM and MATCOM MATH LIBRARY
Mathematica 3.0
MATLAB and Simulink
91.Multimedia
Peter Lipa and his Journeys
Lucka Vondrackova and her Journeys
MpegTV Player 1.0
Peter Nagy and his Journeys
Xaudio
Peter Lipa and his Journeys
Lucka Vondrackova and her Journeys
MpegTV Player 1.0
Peter Nagy and his Journeys
Xaudio
92.Network Servers
Critical Angle X.500 Enabler
DNEWS News Server
Aventail Internet Policy Manager
Aventail VPN
WANPIPE
Zeus Web Server
Critical Angle X.500 Enabler
DNEWS News Server
Aventail Internet Policy Manager
Aventail VPN
WANPIPE
Zeus Web Server
93.Office Tools
94.Text Processing
95.System Administration
Host Factory
PerfectBACKUP+
Venus
Host Factory
PerfectBACKUP+
Venus
96.X Windows Related
Accelerated-X Display Server
BXwidgets
BXwidgets/DB
Laptop, Accelerated-X Display Server
Accelerated-X Display Server
BXwidgets
BXwidgets/DB
Laptop, Accelerated-X Display Server
97.Other Software
ABACUS 4
BBBS
Clustor
FootPrints
Aladdin Ghostscript
ABACUS 4
BBBS
Clustor
FootPrints
Aladdin Ghostscript
98.Users, Groups and Access Permissions
In UNIX/LINUX, there is a concept of user and an associated group
The system determines whether or not a user or group can access a file or program based on the permissions assigned to them.
Apart from all the users, there is a special user called Super User or the root which has permission to access any file and directory
In UNIX/LINUX, there is a concept of user and an associated group
The system determines whether or not a user or group can access a file or program based on the permissions assigned to them.
Apart from all the users, there is a special user called Super User or the root which has permission to access any file and directory
99.Access Permissions
There are three permissions for any file, directory or application program.
The following lists the symbols used to denote each, along with a brief description:
r — Indicates that a given category of user can read a file.
w — Indicates that a given category of user can write to a file.
x — Indicates that a given category of user can execute the file.
There are three permissions for any file, directory or application program.
The following lists the symbols used to denote each, along with a brief description:
r — Indicates that a given category of user can read a file.
w — Indicates that a given category of user can write to a file.
x — Indicates that a given category of user can execute the file.
100.Each of the three permissions are assigned to three defined categories of users.
The categories are:
owner — The owner of the file or
application.
group — The group that owns the file or application.
others — All users with access to the
system.
101.One can easily view the permissions for a file by invoking a long format listing using the command ls -l.
For instance, if the user juan creates an executable file named test, the output of the command ls -l test would look like this:
-rwxrwxr-x 1 juan student 0 Sep 26 12:25 test
The categories are:
owner — The owner of the file or
application.
group — The group that owns the file or application.
others — All users with access to the
system.
101.One can easily view the permissions for a file by invoking a long format listing using the command ls -l.
For instance, if the user juan creates an executable file named test, the output of the command ls -l test would look like this:
-rwxrwxr-x 1 juan student 0 Sep 26 12:25 test
102.The permissions for this file are listed are listed at the start of the line, starting with rwx.
This first set of symbols define owner access.
The next set of rwx symbols define group access
The last set of symbols defining access permitted for all other users.
103.This listing indicates that the file is readable, writable, and executable by the user who owns the file (user juan) as well as the group owning the file (which is a group named student).
The file is also world-readable and world-executable, but not world-writable.
104.ls is used to list the contents of a directory.
If the command ls is written with parameter –l then the command lists contents of the working directory with details. Example:
$ ls –l
105.Moving in Directories
cd try_it
Changes the directory to try_it
pwd Prints present working directory (e.g. /home/smith/try_it)
cd .. Move to superior directory
pwd : Prints /home/smith
cd /home The absolute path
pwd : Prints /home
cd The system is returned to the user home directory
pwd : Print /home/smith
This first set of symbols define owner access.
The next set of rwx symbols define group access
The last set of symbols defining access permitted for all other users.
103.This listing indicates that the file is readable, writable, and executable by the user who owns the file (user juan) as well as the group owning the file (which is a group named student).
The file is also world-readable and world-executable, but not world-writable.
104.ls is used to list the contents of a directory.
If the command ls is written with parameter –l then the command lists contents of the working directory with details. Example:
$ ls –l
105.Moving in Directories
cd try_it
Changes the directory to try_it
pwd Prints present working directory (e.g. /home/smith/try_it)
cd .. Move to superior directory
pwd : Prints /home/smith
cd /home The absolute path
pwd : Prints /home
cd The system is returned to the user home directory
pwd : Print /home/smith
106.The command mkdir my_dir
makes new directory my_dir (the path is given relative) as a subdirectory of the current directory.
makes new directory my_dir (the path is given relative) as a subdirectory of the current directory.
107.Remove Directory
The command rmdir your_dir
removes directory your_dir if it is empty.
The command rmdir your_dir
removes directory your_dir if it is empty.
108.Copy File
The command cp file_1 file_2
copies file_1 to file_2. The both files must be in the same working directory. If they are in various directories, the path must be given.
The command cp file_1 file_2
copies file_1 to file_2. The both files must be in the same working directory. If they are in various directories, the path must be given.
109.Rename and/or Move the File
The command mv file_1 file_2
moves file_1 to file_2
The both files must be in the same working directory.
If they are in different directories, the path must be given.
The file_1 is removed from the disk.
The command mv file_1 file_2
moves file_1 to file_2
The both files must be in the same working directory.
If they are in different directories, the path must be given.
The file_1 is removed from the disk.
110.Remove File
The command rm file_a
removes the file_a from the system
If you use wildcard. For example
rm h*c
you will remove all files beginning with h and ending with c which are in working directory.
If you write
rm *
you will erase all files from your working directory.
The command rm file_a
removes the file_a from the system
If you use wildcard. For example
rm h*c
you will remove all files beginning with h and ending with c which are in working directory.
If you write
rm *
you will erase all files from your working directory.
111.Access Permission of File/Directory
The ownership of the file or directory can be changed using the command
chown <owner> <file/directory name>
The group of the file or directory can be changed using the command
chgrp <group> <file/directory name>
The permissions of the file can be changed using chmod command
chmod -R ### <filename or directory>
-R is optional and when used with directories will traverse all the sub-directories of the target directory changing ALL the permissions to ###.
The ownership of the file or directory can be changed using the command
chown <owner> <file/directory name>
The group of the file or directory can be changed using the command
chgrp <group> <file/directory name>
The permissions of the file can be changed using chmod command
chmod -R ### <filename or directory>
-R is optional and when used with directories will traverse all the sub-directories of the target directory changing ALL the permissions to ###.
112.Access Permission of File/Directory
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