Linux command essay

1. 1> 2> redirect

2. Alias rm = ' RM-RF ' on ~/.bashrc or ~/.ZSHRC

3.date Gets the current time date +%s (the number of milliseconds in 1970)

4.= define variable, = cannot have spaces on either side.

5.$ variable name get variable, set variable

6. function fname () {} Defines a functional fname is the execution of a function (the other scripts are fname () with a ()) fname arg1 arg2 Pass parameters. There is no formal parameter. The get parameter is $ $, the list property is [Email protected]

7.:() {:|:&};: Fork bomb:() defines a function whose name is:: Recursive invocation: |: Variable execution also fork process & decoupling so that the initial ":" function is killed for the two ":" Functions it calls after it is executed; function definition End: Call this function

8. Export-F fname exported function (parameter-f)

9.unset -F fname Delete function unset-v variable name delete variable

10. How to pass parameters: Command-p-v-k 1 file = can be command-pvk 1 file and can be command-pv-k 1 the file parameter can be passed in any way

11.CM1 | cm2 | cm3 is used as a conduit for output and input stdin stdout | is the logo of the piping pipe.

Cat -n means plus line number ls | Cat-n

cat: 1. Displays the entire file at once. $ cat filename 2. Create a file from the keyboard.  $ cat > FileName can only create new files and cannot edit existing files. 3. Merge several files into one file: $cat file1 file2 > file

Cat also has the role of creating files

14.| Save the value on the variable, use $ () to assign the value to the TT tt=$ (ls | cat-n)

15. Write function in one line: repeat () {while:;d o [email protected] && Return;done}

While loop:

Format One While condition   Do Statement

Done

Format three dead Loops

While:

Do

Statement

Done

Format Four dead Loops

While [1]

Do

Statement

Done

Format Five Dead Loops

While [0]

Do

Statement

Done

16. | Od-b Output binary format

Linux command essay