<> The simplest command ：
key word ：date cal pwd cd ls mkdir rmdir cp cat diff head tail wc(word count)
* Current time
dl@dl-virtual-machine:~$ date
* Current date
dl@dl-virtual-machine:~$ cal
* Calendar for the specified year （ Show year round ）
dl@dl-virtual-machine:~$ cal 2020
* Calendar for the specified month （ Show month ）
dl@dl-virtual-machine:~$ cal 1 2020
* View current folder
dl@dl-virtual-machine:~$ pwd
* View the files contained in the folder
dl@dl-virtual-machine:~$ ls
* View details of files contained in multiple folders
dl@dl-virtual-machine:~$ ls -l
* Jump to the general directory
dl@dl-virtual-machine:~$ cd /
* Skip to the specified folder (home) lower
dl@dl-virtual-machine:~$ cd home
* Go back to the previous level ( folder )
dl@dl-virtual-machine:~$ cd ..
* Create a new folder in your location
dl@dl-virtual-machine:~$ mkdir cc( Folder name )
* Clear created folder ( Cannot delete across folders )
dl@dl-virtual-machine:~$ rmdir cc/( Folder name )
* Copy file to another
dl@dl-virtual-machine:~$ cp -r cc( File name copied ) cc1( File name after copying / Copy the previous folder under this folder )
* View the contents of the file
dl@dl-virtual-machine:~$ cat file name ( - The beginning is OK cat)
* Compare two files
dl@dl-virtual-machine:~$ diff folder 1 folder 2
identical ：
inequality ：
* View the header of a file ( The first few lines specified )
dl@dl-virtual-machine:~$ head file name -n 5
* View the last few lines of the file
dl@dl-virtual-machine:~$ tail file name -n 5
* Statistics Number of rows word Number of characters
dl@dl-virtual-machine:~$ wc file name
* Count rows only
dl@dl-virtual-machine:~$ wc -l file name
* Only count the number of words
dl@dl-virtual-machine:~$ wc -w file name
* Count only characters
dl@dl-virtual-machine:~$ wc -c file name
* Screen clear
dl@dl-virtual-machine:~$ clear
Technology