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This article introduces the relevant knowledge of "what are the Linux command formats". In the operation of actual cases, many people will encounter such a dilemma, so let the editor lead you to learn how to deal with these situations. I hope you can read it carefully and be able to achieve something!

Command prompt

When we log in to the server, we will see the following:

[root@localhost ~] #

What does that mean? This is the Linux command prompt. The following describes common command prompts and their meanings

[]: this is the separator of the prompt and has no special meaning.

Root: shows the current logged in user.

@: a separator with no special meaning.

Localhost: the abbreviated hostname of the current system (the full hostname is localhost.localdomain).

~: represents the directory where the user is currently located. In this case, the directory where the user is currently located is the home directory.

The home directory of the superuser: / root.

The home directory of the normal user: / home/ username.

#: command prompt, which is used by Linux to identify the level of user permissions logged in. If you are a superuser, the prompt is #; if you are a normal user, the prompt is $.

Since users have full permissions in their own home directory, it is recommended that you switch to the home directory to operate:

[root@localhost ~] # cd / usr/local

[root@localhost local] #

Note: if you switch the user's directory, the command prompt will become the last directory of the user's current directory local

Basic format of Linuxm command

The basic format of the command:

[root@localhost ~] # command [options] [parameters]

The [] in the command format represents optional, meaning that some commands can be executed without writing options or parameters. So, let's use the most common ls command in Linux to explain the format of the command. If classified according to the command, then the ls command should belong to the directory operation command.

[root@localhost ~] # lsanaconda-ks.cfg install.log install.log.syslog

The role of option

The ls command can be executed without options and arguments, but only the most basic function is to display the file name in the current directory.

[root@localhost ~] # Is-l

Total dosage 44

-rw-.1 root root 1207 January 14 18:18 anaconda-ks.cfg

-rw-r--r--.1 root root 24772 January 14 18:17 install.log

-rw-r--r--.1 root root 7690 January 14 18:17 install.log.syslog

In the above code, if you add a "- l" option, you can see that the content displayed has increased significantly. "- l" means long list, that is, to display the details of the file.

The options for Linux are divided into short format (- l) and long format (--all). The short format option is abbreviated in English and is called with a minus sign, for example:

[root@localhost ~] # ls-l

The long format option is a complete word in English and is usually called with two minus signs, such as:

[root@localhost] # ls-- all

In general, the short format option is an abbreviation for the long format option, that is, a short format option will have a corresponding long format option. Of course, there are exceptions, such as the short format option-l of the ls command, which has no corresponding long format option.

The role of parameters

Parameters are the operation objects of commands, and general files, directories, users and processes can be ordered to operate as parameters. For example:

[root@localhost ~] # ls-l anaconda-ks.cfg

-rw-.1 root root 1207 January 14 18:18 anaconda-ks.cfg

Commands generally need to add parameters to specify who the object of the command operation is. If parameters can be omitted, there are generally default parameters. For example:

[root@localhost ~] # ls

Anaconda-ks.cfg install.log install.log.syslog

No arguments are specified after this ls command, and the default parameter is the current location, so the file name in the current directory is displayed.

This is the end of the content of "what Linux command formats". Thank you for reading. If you want to know more about the industry, you can follow the website, the editor will output more high-quality practical articles for you!

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