Unix

OS system software applications are mainly designed to run PC or Mac systems as a whole. Operating systems are the cradle for word processing programs, along with other software applications and media. Utility software, however, is designed to help the OS system run more efficiently and smoothly. Utility software can include disc monitoring and repair tools, along with programs that ensure system drivers are up to date across the board.

Some may think that the vi editor is too cryptic in its use of commands; i.e. it is not very intuitive in terms of doing edits. Other editors seem to allow users to 'take' to them in an easier fashion.

However, if you use it long enough it becomes (like anything else) second nature.

Unix is a mainframe operating system that was invented at Bell Labs in 1969. Linux is actually a free software (also known as open source) version of the Unix kernel, rewritten from scratch for the 'PC' (x86) hardware standards, with all the improvements that Linus Torvalds felt were needed. The Linux kernel plus the GNU software, creates the base system of what people generally refer to as 'Linux'. Add XWindows and a window manager like GNOME or KDE, and you get desktop 'Linux'.

Linux is one example of "copyleft" software, a concept introduced by Richard Stallman, founder of the GNU project, and the Free Software Foundation. Like copyright, copyleft means no one else can copyright and own a piece of creative work. But where copyright = all rights reserved, copyleft = all rights released (to use, copy, modify, and sell).

Free software systems can be fast evolving systems because the code is open to everyone, and when someone makes an improvement to a program it is shared with the maintainers. If it's good it will be incorporated into future versions of the program, available to all for free. Some 'flavors' of GNU/Linux are packaged and 'sold', but in reality what is being paid for is the service package and tech support of the packaging company, and source code must be provided with all working versions. Linux itself is available for free to anyone with access to the internet. Other reimplementations of unix for x86 include operating systems like the BSD family, Sun's Solaris, and HP Unix.

The 'head' command will list out certain number of lines in a file from the beginning. The standard is to list the first 25 lines, but you can change that:

head -100 myfile

will list out the first 100 lines of myfile.

The same way you create any other program, by designing it and then coding it. A shell program is no different to any other program in terms of how it is created. Its purpose is simply to provide access to the applications and utilities, perhaps organise them in some way, and to present key system components such as a clock or calendar, as well as system notifications from background services. In Microsoft Windows, for instance, Windows Explorer is the default shell program and this provides a desktop, taskbar, start menu and notification area. However, only the first instance of Explorer provides the shell. All other instances of Explorer simply open navigation windows. But while you cannot replace Windows Explorer itself (it is an integral part of the operating system), you can replace the shell component.

All Unix systems provide a 'find' command that searches for specific files in a given directory. To find a file that has the word "foo" in the /usr directory, I would type:

$ find /usr -name *foo*

For more information, see 'man 1 find'.

A page fault in any operating system will occur when a reference to memory indicates that the actual information has been paged out to disk, and is not available in memory at the present time.

When the page fault occurs, the system has to swap that page back into memory before it can reference the memory location. This is how virtual memory was implemented.

Page faults should be transparent to the program; it doesn't know or care if the memory was resident or not, since the net effect is to make that memory available to the program, whether it was paged out or not.

Unix is a computer operating system. It tells the computer how to work. Your computer is actually quite stupid. It knows how to do one thing. When it starts up, it knows how to do one of two things, they are either start spinning the hard disk, or move the memory from location a into the processor. Then the operating system starts telling the computer what to do. It might tell it to take orders from the screen, to add and subtract, to print, to use the internet and how to use the internet, or to do something else.

A "process" is a program. In multitasking environments such as Unix or Windows - in fact, in most modern operating systems - the computer can run multiple processes at the same time. Note that not all of such processes need to have a visible window - some can be hidden from the user, until you use a special tool or command to list the processes.

The computer usually uses its input/output channels to access secondary storage and transfers the desired data using intermediate area in primary storage.

November 3, 1971

Unix is no longer a single operating system, and as such no single company makes it. Historically, Unix was created by AT&T. Nowadays, operating system collectively referred to as "Unix" are created by companies such as Sun (Solaris), Hewlett-Packard (HP-UX), IBM (AIX), and Apple (Mac OS X).

In general each command in a script file is on a separate line, so it is terminated with a line terminator character (put it automatically when you press the Enter key).

Unlike some programming languages, a script file does not need a special terminator for the end of the line.

du is a command the reports on the Disk Usage of the filesystem.

Unix is the name of both a general specification for an operating system to meet, and the first system to meet that specification. Xenix is an implementation made by Microsoft in the late 1980s that met the Unix specification.

The 'mount' command with no options will list out all of the mounted filesystems currently in use and their 'mount' options.

This command is used by the administrator to make available partitions that are currently offline.

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Advantages

• Full multitasking with protected memory. Multiple users can run multiple

programs each at the same time without interfering with each other or

crashing the system.

• Very efficient virtual memory, so many programs can run with a modest

amount of physical memory.

• Access controls and security. All users must be authenticated by a valid

account and password to use the system at all. All files are owned by

particular accounts. The owner can decide whether others have read or write

access to his files.

• A rich set of small commands and utilities that do specific tasks well -- not

cluttered up with lots of special options. Unix is a well-stocked toolbox, not a

giant do-it-all Swiss Army Knife.

• Ability to string commands and utilities together in unlimited ways to

accomplish more complicated tasks -- not limited to preconfigured

combinations or menus, as in personal computer systems.

•

• The traditional command line shell interface is user hostile -- designed for the

programmer, not the casual user.

• Commands often have cryptic names and give very little response to tell the

user what they are doing. Much use of special keyboard characters - little

typos have unexpected results.

Disadvantages of UNIX

• The traditional command line shell interface is user hostile -- designed for the

programmer, not the casual user.

• Commands often have cryptic names and give very little response to tell the

user what they are doing. Much use of special keyboard characters - little

typos have unexpected results.

• To use Unix well, you need to understand some of the main design features.

Its power comes from knowing how to make commands and programs

interact with each other, not just from treating each as a fixed black box.

• Richness of utilities (over 400 standard ones) often overwhelms novices.

Documentation is short on examples and tutorials to help you figure out how

to use the many tools provided to accomplish various kinds of tasks.

the command is - ls there are other options and flags for the ls command which can be viewed by typing man ls if you type 'man ls' in a google search, it will show you the same manual

Internal commands are executed by the shell and do not exist as a separate binary program. You can find out which of these there are by looking at the 'man' entry for the shell you are using.

External commands can be found in various directories, such as /bin, /usr/bin, etc.

What was created to define a standard directory structure and common file loc

'smbpasswd' is the program you are looking for. Read the manual 'man smbpasswd' for more information. You must be root or run with sudo to change other users passwords.

Change password with the command 'smbpasswd <username>'

# smbpasswd bob

or

$ sudo smbpasswd bob

NOTE: You may also need to enable the user after you set the password

# smbpasswd -e bob

or

$ sudo smbpasswd -e bob

Linux, Minix, Coherent, FreeBSD, etc. These are all clones of Unix

The UNIX OS is an operating system, which has the primary responsibility of managing security and resources for users. It has the same "purpose" as any other operating system, such as Windows, z/os, VMS, etc.