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How to display commands after typed letters in Linux?

The tab key is a shortcut key for completing commands.

Linux refresh shortcut key?

Press F5 to refresh the page. Press "F5" to refresh, and press "Ctrl F5" to force a refresh.

Please answer, "Terminal control key Ctrl C in Linux?

tty (teletypewriter) telex machine, press a button here, the host side receives a data, the host side transmits Outputs a piece of data, and the telex machine prints a character.

This is the ancestor of all terminals. Inputting characters and printing characters are integrated, and what runs in the host is called a program.

I input a character, and the host receives a character. Then I think it will be troublesome to wrap the line, because this is a control character, so an interpreter must be able to analyze and process the input characters. This interpreter is called a shell.

The emergence of the monitor separated input and output. With the development of the times, we no longer need telex machines. We plug the monitor and keyboard into the host computer. The monitor is responsible for displaying the output of the program, and the keyboard is responsible for input. characters into the program, these two are still called terminals.

Because everything in Linux is a file, and the terminal is also a file, you can create a virtual terminal, but these files (virtual terminals) must also be used. Complete the input of information into the host and accept the data from the host.

The console is a terminal that is directly plugged into the host and interacts with the host system, and directly controls the host.

Later. You don’t need to plug it in directly, it is a virtual console, which is characterized by being able to control core things. It is also used to refer to a lower-level terminal that can only process characters and control the host through characters. This concept is the command line window, which is not available here. The mouse is different from the graphical terminal.

The pseudo-terminal is a terminal simulated by a terminal emulator program such as xterm. It consists of two terminals. The terminal consists of a pseudo terminal master ptmx and a pseudo terminal servant pts. Operations on the terminal master will be transmitted to the terminal servant and vice versa. They are mostly used in remote login state. When I operate the remote host on the computer, I operate the remote host. The terminal master on the host computer, and the remote host thinks that a person is operating on his own terminal, that is, the terminal servant. The information told by the program on the host computer will be transmitted to my computer through the terminal master.

The numeric keyboard of the Linux system is malfunctioning?

1. If all the keys are vector, first check each key on the keyboard. It may be that one keyboard is pressed and the key is pressed. If the keyboard is damaged, it may be caused by the aging of the keyboard or dirt on the circuit board inside the keyboard, which may cause the keyboard to malfunction. In this case, it is recommended to replace the keyboard with a new one. It is not very expensive.

2. Check whether the keyboard interface is loose or has poor contact. If the user knows how to use a multimeter, he can use a multimeter to detect whether the computer keyboard is damaged.

Learn Linux file types and suffixes a day at a time?

Common file types in Linux

General files

This is the file we list through ls-l. The first character in the first column is - , according to the content of the file, it can also be divided into several categories:

Plain text file (ASCII): This is equivalent to Notepad, called a plain text file, and we can directly read the contents of the file. This kind of files occupies a lot in Linux systems.

Binary file (binary): The executable file (scripts) in the Linux system is a binary file, and this file must have x permissions to be executed. Some commands in our system are files of this type.

Data format file (data): In the Linux system, some programs will read certain databases when running. These files are data files. For example, the last command we mentioned earlier calls /var/log/wtmp. If we use the cat command to view the /var/log/wtmp file, you will find that it is all garbled.

Regarding some other file types, such as connection files, device files, data interface files (sockets), pipe files (pipe), etc., these are also special file types, we only need to understand them Yes, in the subsequent study, you just need to know what it is when you see it. If you want to learn more deeply, then find relevant information and study slowly, such as how to view a data file, etc.

Linux file suffix

We also said at the beginning that on the Linux system, the requirements for this suffix are not as strict as Microsoft's win system, but In order to make it easier to confirm what kind of file the file is, the corresponding suffix is ​​added at the end. If the contents of a file can be read using the cat command, after we change the suffix, it can still be read using cat.

We also know that on Microsoft's win system, commonly used executable files generally end with .com, .bat, and .exe. It's different on our Linux system. I can add X (executable) permissions to any file, but whether it can be executed successfully depends on the content of the file itself. An important point here is that there is a difference between being able to be executed and being able to be executed successfully. For example, we have an install.log file in the home directory of the root user. We add X permissions to it. Although it is an executable file, there will be no results after execution because the content in this file is not accessible to our system. Executed, of course he failed to execute it!

So, in order to make it easier for us to understand what the files in the system are for. The Linux system will still use the corresponding suffix name to indicate the type of file. Let's take a look at some common suffixes

.sh: These are usually some scripts files we write ourselves, usually written through the shell, so they are represented by .sh.

.z, .tar, .tar, .gz, .zip, .tgz: This type of file is a compressed file, but the compression method used is different.

.log: This type of file is a log file.

.conf: This type of file is some configuration files, which are most commonly seen on Linux systems.

.rpm: This is a Red Hat software package. Of course, the suffixes of the software packages used by different Linux distributions are different.

.php, .jsp, .html, .css: This category is all website type files.

Of course, there are some other suffixes, which don’t have much meaning. They are just for our convenience to identify. Let’s take a brief look at them.

This length is already very long, enough for us. In the subsequent study, you will find that on the Linux system, many software names are very long. It will be a waste of time if you type each word one by one, and sometimes you will make mistakes. Isn't this too inconvenient? Of course not. Long file names help us know what this file is for (I think so). It is actually convenient for us. In order to prevent us from typing so many words, there is an important function key on the Linux system, which is TAB. This has a completion function. Just type the first few words and press TAB to complete them. If you press If used twice, content related to these words will be displayed.

Haha, if friends who use Linux don’t know this function, or don’t know how to do it, then it’s a failure!

Naming rules for files in Linux systems

We know that on Linux systems, commands are basically used to operate. The shell we use has many special features. Characters, if our file name is the same as the special characters in this shell, it will be difficult to handle, so when we name the file, we should avoid some special characters while making it easy to identify. We list them below. For your reference (it’s not that you can’t command these characters, it’s just recommended to avoid them).