<> 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