Question：

Compare usages for more than two types of operating systems. for example,  how to create directory.

 

 

• Windows
  
  
  
  • Keyboard win+R, call up the run window, type cmd to open
  
  
  
  

 

• The create folder can be created using the md <folderName> or mkdir <folderName> commands, where md and mkdir both mean to create a new directory make directory. The complete command is md [drive:\][path\]new directory name, For example: md c:\zhaochenjiang\folder

 

 

 

• The directory was created successfully

 

• Mac OS
  
  
  
  • First cd to the path where you want to create the folder
  
  
  • Create a folder using the mkdir directive
  
  
  • The directory was created successfully
  
  
  
  

 

 

 

3. Introduce

 

（1）Windows terminal: 

All software is installed on the server and runs on the server, and the results are sent to the terminal display. The terminal is only responsible for displaying and mouse keyboard input, not running the software. When different terminals are logged in, the server opens up a space for it, so running the same program on different terminals does not cause conflict. The operating effect of the Windows terminal depends on the server, which is not required for maintenance of the device and hardware and software upgrades, so it is also called "thin-client". The thin-client Windows terminal can configure, manage, maintain, support, and run various applications on the server. It has the advantages of high efficiency and safety. Windows terminal is a system that accesses and USES all software and hardware and data resources on the terminal server through ICA/RDP protocol. The software runs completely on the server and displays the results on the terminal.

（2）Linux systems: 

Like other unix-like systems, Linux itself is based on command lines. Its console, which is what Linux really is. Linux provides more than one terminal in the console, enabling multiple users to log in simultaneously, including at the same time. Generally, the Linux distribution provides 7 virtual screens, 1~6 is the console terminal, and the 7 top runs X-Window. As stated earlier, the console terminal "is the true face of Linux." You can only "count" because the command-line programs running in each terminal are not the terminal itself, nor Linux itself. Many command-line programs are essentially peripheral programs called shells. "Shell", the shell. You see something from the name. It contains the user interface function, which is responsible for receiving input from the user, and then sending it to the Linux kernel for processing. If there is an output, it also displays the output. The shell can also perform batch processing with several commands. A slightly more powerful shell script already has a high-level language syntax. In general, the "terminal" is opened on the console terminal or in the graphical interface, and a shell is started by default to host the user. Can start first think terminal is the parent process, the process will perform the login procedure, in order to handle the login action, after the completion of the login, the login will perform user shell, at this moment is the default for the user assigned a shell. The shell executes the commands that the user types. Also, the shell can open its sub shell to perform user input, and when the subshell ends, it sends a signal to its parent. So when the user leaves the system, its login shell tells init, and init knows that it will create a new process for that terminal, and then the loop repeats itself. You can start another shell in the shell command line. The general command to exit the current shell is "exit". If the current shell is started after the console login, the "exit" is equivalent to "logout". The background program started in the shell will not terminate due to normal exit. The so-called abnormal exit, means to kill the shell forcibly; Closing a terminal with a "fork" in a graphical interface is also a way to force a shell off. There are many kinds of shells, each with its own characteristics. The most widely used shell is "bash", and the main Linux distribution is used as the default shell. "Bash" and other mainstream shells support multiple commands at one time, supporting the startup of background programs. If you want to execute multiple commands in turn, use ";" Separated; If you want the program to run in the background, add "&" after the command.

（3）MAC OS： 

OS X's command line, I've never been called "friendly" by me; Instead, we respect and understand each other, not confuse each other. (well, the mutual respect between people and code Windows is the same.)

The average person should not have any reason to access the terminal, and apple's command-line interface application actually allows you to access a lot of clever and shortcuts... If you want to peek.

What is a terminal?

Apple's terminal application is the direct interface of OS X's bash shell - part of its UNIX base. When you open it, the terminal displays a white text screen, and by default you log in with your OS X user account.

The following is an important part: using the system administrator account and password, you can directly adjust almost all the content of the computer software code; This means that although this small window provides great power, it brings great responsibility. In short, be careful before using the terminal to execute commands, and make sure you understand what you're typing.

You can also use a terminal to securely connect to other machines, network servers, or even create your own scripts, but these are another day's methods. Now, we'll focus on using Terminal to explore our own computers.

Basic terminal commands you should know.

Before we get into the fun of things, let's learn some basic terminologies and commands. These frameworks form a framework for more complex interactions (that is, interesting things).

How to execute terminal commands?

You can type content in the terminal window until you turn blue on your face, but only after pressing the Return key on the keyboard. At this point, if you type the wrong thing, it will return an error, or execute the command.

(4)、the difference between r\ r\n \t.

\n soft enter:

In Windows, it represents the beginning of a line break and back to the next line. That's the same thing as the \r in Mac OS.

In Linux, Unix only means line breaks, but not the beginning of the next line.

\r soft  space:

In Linux, Unix means returning to the beginning of the line.

In the Mac OS, it's the beginning of the line that returns to the next line, which is equivalent to the effect of \n in Windows.

\t jump (move to the next column).

They are valid in double quotation marks or delimiter strings and are not valid in a single quoted string.

\r\n is commonly used to represent the return key on the keyboard, or to use \n.

\t represents the TAB key on the keyboard.

Line breaks in the file:

Linux, Unix: \ r \ n

Windows: \ n

Mac OS: \ r

Corresponding:

\n LF or 0x0A(10) in ASCII

\r CR or 0x0D(13) in ASCII

\t horizontal TAB -HT or 0x09 in ASCII (9)

\ \ the backslash

Operator \ $dollars

\ "double quotation marks

\ 'single quotes