(1)
The pipeline Unix allows the output of a program to input as another program, and multiple programs look like a pipeline. Through the combination of various simple tasks, a larger more complex task can be completed, and the convenience of operation is greatly improved. Later, the DOS operating system also borrowed and provided this mechanism. (2) The powerful shell UNIX command interpreter is implemented by the shell. UNIX provides three powerful shells, each shell itself is an interpretation high-level language. You can create countless commands through user programming, easy to use (3)
(1) KERNEL (kernel)
(2) Shell (shell)
(3) Tools and applications
UNIX Kernel (UNIX core) is the core of the UNIX operating system, the operation scheduling UNIX machine, directly controlling the resources of the computer, protecting the user program unfolded in an intricate hardware event detail.
UNIX Shell is a UNIX special program that is a UNIX kernel and user interface, which is a Unix command interpreter, and is also an interpretative advanced language. There are three common shells:
Shell type
Abbreviation
command
main feature
Bourne Shell B Shell SH is the oldest, the most widely used, each Unix is available. Korn Shell K Shell Ksh is an expansion of B Shell, compatible with B shell. C-shell
The CSH format is a bit like C language. Strong function, order memory is slightly, and is more popular among colleges and colleges.
General system defaults to Bourne Shell, this article takes this shell as an example.
To change the current shell to other shells, just type the corresponding shell command at the operating system prompt. If you enter the command under other shell:
KSH
Just entered the K shell.
(4) Several nouns related to UNIX
The terminal (TERMINAL) terminal is an interface device for users and computers for real-time interaction. The terminal is typically composed of a display, a keyboard, and a terminal controller, and some have a mouse. The display and keyboard are connected to the terminal controller, and the terminal controller is connected by a universal port (such as serial port) and the computer host. The user communicates over the terminal and computer. A UNIX host can connect multiple terminals. Terminal is divided into two categories: character terminals and graphics terminals.
The simulation terminal runs a particular program on a computer and uses a computer as a terminal of another computer. The current simulation terminal and the Unix host have the main connection to include network connection and serial connections.
Console This is a special terminal that consists of a display, a keyboard (and mouse), which connects to a dedicated interface of the host (monitor interface, keyboard interface, mouse interface). Generally, one host can only pick one console, the console can complete the work that the normal terminal cannot be completed: very important information (such as serious error message) can only display, some special tasks (such as execution repair work) on the console ) Can only be done on the console. In addition to achieving the above special functions, the console can also work like other terminals.
User Name (User) is a multi-user operating system that allows multiple users to use simultaneously. Each user has username, login password, and operational privileges. You must first log in every time you use UNIX: Enter your username and password. General User's UNIX operating system prompt is generally "$".
Several users of the user group can form a group, and users can share information in the same group.
Root User Unix's superuser, has privileges that have other users. The Root user's UNIX operating system prompt is generally "#".
Process is a program being executed. UNIX allows multiple processes to exist simultaneously, and each process has a unique generation name of the process identifier (PID --- "ID). Foreground process can be directly interacting with the user directly. The front process can receive the keyboard input and display the result on the display. The Unix program launched in the default state is running on the front desk.
Background Process does not directly interact directly with the user. Users typically do not feel the operation of the background process program. Unix has a lot of system processes in the background.
Device (Device) or device file represents a hardware, such as a disk, floppy disk, and serial port. Unix is done through the device files for hardware. The device file is placed in the / dev directory, such as / dev / hd0 represents the first floppy disk drive.
Raw Device is also known as a bare device, without processing equipment files. The original device file name is started with R, such as / dev / rhd0 represents the first floppy disk drive original device.
(5) Unix case sensitive. Therefore, pay attention to the case of the directory name and the case where the command is written (6) Unix files No dedicated expansion name, so there are multiple decimal points meaningless, just difference. Unix ".name" Represents Hide File (7) File Access Permissions Owner Group Other R W X R W X R W x From 2 to 10 starting from 2 to 10 in LS -L, it should correspond to access rights of these three users.
Format 2: Absolute mode (absolute_mode), the command format of the symbol mode is as follows:
Chmod XYZ File ...
X, Y, Z is 0-7 number, respectively, indicate the host, user group, and others to access the file. The value formula of x, y, and z is:
A * 4 B * 2 C
among them,
A = 1 indicates readable, A = 0 means unread;
B = 1 indicates that can be written, b = 0 means not to be written;
C = 1 indicates that can be executed, and C = 0 means it is not executable;
(8) Chown changes the group of the owner ChGRP changes the group (9) UNIX redirection and pipe redirection>
> Redirection output >> Redirection output and append to the tail Pipeline | (10) The NNIX host is a shutdown process for the root user to type: # shutdown -g0 -y Indicates that it is turned off immediately. Enter a single user mode by multi-user mode, executing the following command: # shutdown -g0 -y su [Note] You must turn off the host power when you run the shutdown command and you have allowed the shutdown information. No information allowed to shut down, do not turn off the host power. (11) Interpretation UNIX command View Disk Free Space DF -V View Disk Usage DU [File Name] (12) Hard disk name habit with bus controller CWTXDYSZ C: Logical Controller Number T: Physical Bus Target Number D: Drive Number S: slice (or partition) Number (0 to 7) W: If there is only one controller in the system, the value of W is usually 0 x: For the SCSI controller, X is the target address set for the rear switch of the component Y: Y is the drive letter connected to the target. If the controller of the hard disk is embedded, Y is 0 z: is the partition number, the code code is 0 to 7, specifying the entire hard disk, the value is 2. Specify a partition of a hard disk with a bus controller (SCSI or IPI), which can specify the device name: / dev / dsk / cwtxdysz (block interface) or / DEV / RDSK / CWTXDYSZ (original interface) example: / dev / RDSK / C0T0D0S0; First controller of the first SCSI target address of the first partition / DEV / RDSK / C0T0D0S2 of the first hard disk; the first hard disk of the first SCSI target address of the first controller (the third partition of the first hard disk of the first controller ( 13) Set the step of setting up the network (1) Log in to UNIX with root users (2) View whether HOSTS, NETWORKS and GATEWAYS files exist in / etc directory, if there is no creation (3) Modify the three file content to ensure correct parameters, pay attention to the relationship between the three file parameters (4) Reconnect the kernel (for SCO UNIX can run sysadmsh "SYSTEM-> kernal-> reelink) (5) Run Reboot Restart UNIX
