A preliminary study of Linux--basic knowledge

1 Everything is a file (contains hardware)

2 small, single-use programs

3 linking programs to accomplish complex tasks together

4 Avoiding the confusing user interface

5 configuration data is stored in text

Two Linux important concepts what the shell is

In the process of learning Linux, the word shell is often heard. Maybe everyone in the use of Windows when this feeling, I want to listen to songs, I open a player, then the speaker can make a sound, to print a document, we just click on the program in the Print button, printing will automatically print the document. But we did not manually control the speakers and printers and other hardware equipment, because the system has been done for us. In fact, we can call Windows shell, we do not have to know the principle of the printer, and do not need to control it, we only need a gentle click of the mouse, the system for us to control these hardware devices.

When the user uses the system, in fact, and the shell in dealing with, our windows has a variety of features graphically expressed, when the user issued instructions, actually first send these instructions to the shell, and then by the shell to translate the user's instructions to the kernel, The kernel then controls the work of the hardware. The kernel then sends the hardware to the shell, and finally the shell returns the hardware's work information and situation.

The 1 shell is the user interface of the Linux system and provides an interface for users to interact with the kernel, which accepts commands entered by the user and sends it to the kernel for execution.

2 Shell is also known as the Linux command interpreter (commands interpreter)

3 Shell is a high-level programming language

Three of the shells used by CentOS

The gun Bourne-again Shell (bash) is one of the most important tool software in the gun program and is currently the Linux standard Shell, compatible with SH

Echo $SHELL shows what SHELL is currently in use (note case)

Cat/etc/shells shows all shells used by the current system

Follow-up attach to explain 5w1h thought

"5W" was in 1932 by the American political scientist Lasville first put forward a set of communication model, after people's continuous use and summary, and gradually formed a set of mature "5w+ih" model.

5W1H analysis, also known as the six-way analysis, is a method of thinking, can also be said to be a creative technique. It is the choice of the project, operation or operation, from the reason (why), the object (what), the place (where), time (when), people (WHO), methods (how) and other six questions to think about. This seemingly ridiculous, very naïve questioning and thinking method, can make the content of thinking deepen, scientific. See the following table for details:

Table: 5w1h Analysis method

　　

Object

What products does the company produce? What parts does the workshop produce? Why do you want to produce this product? Can you produce anything else? What exactly should I produce? For example, if this product does not make money now, change a profit high

Place

Where did the production go? Why do you have to do it in this place? How about a different place, okay? Where in the world should I do it? This is the choice of workplace should be considered.

Time and program

For example, when is this process or component being done now? Why do you do it at this time? Can you do it at any other time? Can you refer to the previous procedure? At what time should I do it?

Personnel

Now, who's doing this thing? Why did you let him do it? If he is irresponsible and has a big temper, is it possible to change someone? Sometimes a person, the whole production will be up.

Means

The method is the process, for example, how do we do it now? Why do you do it this way? Is there any other way to do it? What the hell should I do? Sometimes the methods change, and the whole world changes.

[Edit four techniques for analysis of]5w1h analytical methods

Cancel

is to see the scene can not rule out a process, if you can cancel the process.

Merge

is to see if it is possible to combine several processes, especially in the assembly line production to improve and improve efficiency immediately.

Change

As mentioned above, changing the order, changing the process can improve efficiency.

Simplified

Make complex processes simpler and more efficient.

No matter what kind of work, process, action, layout, time, location, etc., can be used to cancel, merge, change and simplify the analysis of four techniques to form a new person, object, place the combination of new concepts and new methods. As shown in the following:

Figure: Four skill analysis diagram

A preliminary study of Linux--basic knowledge