How do you back up commands in Linux?

In Linux, how do you back up commands? in linux, this road is quite rough! Unfortunately, I still cannot carry a few commands... Lsdircdssh is the most common .. In the face of this dilemma, I came up with all the tricks and couldn't carry them back. I just checked out some commands ..... In Linux, how do you back up commands? in linux, this road is quite rough! Unfortunately, I still cannot carry a few commands... The most likely to be ls dir cd ssh, no more .. In the face of this dilemma, I came up with all the tricks and couldn't carry them back. I just checked out some commands .. Therefore, we will introduce the introduction, summary, and query commands to query all linux commands ([Tab] completion commands) and open a Terminal at will ), press two [Tab] [Tab] Display all 2384 possibilities (y or n) to Display all 2384 possibilities? There are 2384 types of commands, but I can't do it anyway. no matter you can't do it, I can't do it anyway. [Html] [Tab] Key, with "command completion" and "file completion" features. If you do not enter anything, Press [Tab] [Tab] and the system will retrieve the command with a null value. all the commands will be retrieved. So we can find all the commands. If you forget the file name (File completion), open the terminal, enter cd w and press [Tab]. then, the folder name will be automatically completed. now that you know so many commands in this directory, how to use it? At this time, we will pay homage to the man and info commands. Artifact 1: The man command is commonly known as "finding a man", the abbreviation of manual, and the meaning of the operation instructions. you can use this command to view how to use the command you want to view. [Html] format: man [space] [command to be viewed]. for example, if you use the common command ls to input man ls and press enter, the ls information is displayed, this page is called man page. The first line of [plain]: ls (1) number 1 indicates that a common user can use the following command in shell: ps: man number: among them, 1, 5, 8 should remember, 1 is the user command, 5 is the configuration file, 8 is the system command requires root permission. Is to use man query to obtain man content parts [plain] NAME introduction SYNOPSIS command syntax DESCRIPTION command complete DESCRIPTION (this part is important) OPTIONS Parameter FILES related File example see also other reference BUGS known bug man page Operation [plain] Mark page Flip/123 search down 123? 123 search up 123 and then press u to view the previous result. Press n to view the next result. q: Exit man. the storage path of man is usually in the/usr/share/man Directory, if there is no slight difference in version, you can try to check the ls to see the second: info command. if man is a man, info is a woman, why? It's just a matter of emotion ~ Both commands can query command usage or file format, but man is displayed at a time. Info is divided into one page and one node is displayed. [Plain] format: info [command to be viewed] Similarly, let's take a look at the common command ls enter info ls and press enter to explain a little: [plain] the first line: the File explanation page is from the document Node. the current Node is Next, and the Next Node is Up. Next, the text is started under the previous Node. you can see it yourself. The Complete English document is as follows, when the English language is improved, the "info" operation [plain] space key goes down to flip the page [Enter] to Enter the node B cursor next to node n pointed by the current cursor to node n, to the end of node B cursor to start e cursor? Command list q exit info page info to store the directory/usr/share/info: other instructions/usr/share/doc. so I am scared of linux, ask a man to teach me the command. If you forget the command, go to [Tab] [Tab] and help me think about it.