[Turn]linux under the terminal common commands and the VI command to modify the file and save the use method

Let's start by introducing the general role of the various directories under Ubuntu:

/

This is the root directory, a computer has only one root directory, all the files are started here. For example: When you enter "/home" in the terminal, you are actually telling the computer to start with the/(root directory) and then go to the home directory.

/root

The directory of the system administrator (root user). As far as the system administrator's authority is, I'm not talking nonsense here. Therefore, be careful with the root account.

/boot

system startup files, all files related to system startup are saved here.

/bin

Here is the procedure for storing the system.

/etc

The system configuration files are mainly stored.

/dev

The main store is the files related to the device (including peripherals) (Unix and Linux systems treat the device as a file). Do you want to connect the printer? The system starts working from this directory. There are also some disk drivers, USB drivers, etc. are put in this directory.

/home

Your personal data is primarily stored here. Each user's settings file, the user's desktop folder, and the user's data are all placed here. Each user has his or her own user directory, located at:/home/user name. Of course, the root user is excluded.

/tmp

This is the temp directory. For some programs, some files are used two times a time, they are no longer used, and files like this are placed here. Therefore, do not put the important data here oh.

/usr

In this directory, you can find additional tools that are not suitable for use in/bin or/etc directories. Like games, some printing tools and so on. The/usr directory contains many subdirectories: The/usr/bin directory is used for storing programs, and/usr/share is used to store some shared data, such as music files or icons, etc./usr/lib directories are used to store those that cannot be run directly, However, it is a function library file that is necessary for many programs to run. Your package Manager will automatically help you manage the/usr directory.

/opt

There are some optional programs that are mainly stored here. Would you like to try the latest Firefox beta? Put it in the/opt directory, so that when you're done trying to erase Firefox, you can simply delete it without affecting any other settings on the system. The program installed in the/OPT directory, all of its data, library files, etc. are placed under the same directory.

Usr/local

The main store is the software that is installed manually, that is, software that is not installed through "new" or apt-get. It has a similar directory structure to the/usr directory. Let the package Manager manage the/usr directory and put the custom script (scripts) under the/usr/local directory.

/media

This directory is used to mount the USB interface of the mobile hard disk (including USB stick), CD/DVD drive and so on.

One, Linux under the terminal Common command

Ubuntu Terminal Common Commands
# CTRL + L-Clear screen
# CTRL + C-Abort command
# Ctrl + D-exits the shell as if it could also represent EOF
# CTRL + Z-the current process is placed in the background and FG is restored.
# Ctrl + R-Find from command history
# CTRL + A-cursor moves to the beginning of the line
# CTRL + E-the cursor moves to the end of the line
# Ctrl + U-clear the cursor to the beginning of the character
# Ctrl + W-clear the cursor before a word
# Ctrl + K-clears the character of the cursor to the end of the line
# CTRL + T-swap the first two characters of the cursor
# Ctrl + Y-paste the characters that were removed from the previous Ctrl+u class command
# CTRL + P-Previous command
# CTRL + N-Next command
# Ctrl + V-Input control word such as CTRL + V.

Second, vi command to modify the file and how to use the Save

The VI Editor is the standard editor for all UNIX and Linux systems, introducing its usage and a small number of instructions. Because the VI editor is exactly the same for any version of UNIX and Linux systems, you can learn more about it in any other place where VI is introduced. VI is also the most basic text editor in Linux, after learning it, you will be in the world of Linux unimpeded.

Before all commands are executed, press ESC first

Basic concepts of 1 VI

Basically, vi can be divided into three states, namely command mode, insert mode (and bottom line mode), and the function of each mode is as follows:
1) command-line mode

Controls the movement of the screen cursor, the deletion of characters, words, or lines, moving and copying a section and entering insert mode, or to last line mode.

2) Insert mode

Only in the Insert mode, you can do text input, press "esc" to return to the command line mode.

3) Bottom Line mode

Save or Exit VI, or you can set the editing environment, such as looking for a string, listing line numbers ... such as

In general, however, when we use the VI to simplify the two mode, that is, the bottom row mode (last lines) is also counted in the command line mode (commands mode).

Basic operation of 2 VI

A) Enter VI

After the system prompt symbol to enter VI and file name, go to the VI Full screen editing screen:

$ VI myfile

However, it is important to note that after you enter VI, you are in command mode and you want to switch to insert mode to enter text. First Use VI people will want to use the next key to move the cursor, the result of the computer has been a beep, the gas to death, so enter the VI, do not move, switch to "insert mode" and then!

b) switch to insert mode to edit the file

Press the letter "i" under Command mode to enter "Insert Mode", and you can start typing the text again at this point.

c) Toggle of Insert

You are currently in "Insert Mode", you can only enter text, if you find the wrong word! To move back with the cursor key, delete the word, then click the "esc" key to go to "command mode" and then delete the text.

d) Exit VI and save the file

Under Command mode, click the ":" colon key to enter "last line mode", for example:

: w filename (enter "w filename" to save the article with the filename you specified)

: Wq (input "wq", save and Exit VI)

: q! (Enter q!, do not save the mandatory exit VI)

3 command-line mode function keys

1). Insert mode

Press "i" switch into insert mode "insert mode", press "I" into the insertion mode is the beginning of the cursor from the current position to enter the file;

After pressing "a" into insert mode, the text is entered from the next position at the current cursor position;

When you press "o" to enter insert mode, you insert a new line and enter text from the beginning of the beginning.

2). Switch from insert mode to command line mode

Press the "esc" key.

3). Move the cursor

VI can be directly on the keyboard with the cursor to move up and down, but the normal VI is the lowercase English letter "h", "j", "k", "l", respectively, control the cursor left, bottom, upper, and right one grid.

Press "ctrl"+"b": The screen moves one page to the back.

Press "ctrl"+"f": The screen moves one page to the front.

Press "ctrl"+"u": The screen moves the half page toward the back.

Press "ctrl"+"d": The screen moves the half page toward the front.

"0" by number: Moves to the beginning of the article.

Press "g": Move to the end of the article.

Press "$": Moves to the end of the line where the cursor is located.

Press "^": Moves to the beginning of the line where the cursor is located

Press "w": Cursor jumps to the beginning of the next word

Press "e": Cursor jumps to the end of the next word

Press "b": Cursor back to the beginning of the last word

Press #l: The cursor moves to the first # position of the line, such as: 5l,56l.

4). Delete text

"x": Each time you press the cursor, delete the "after" character at the position where the pointer is located.

#x: For example, "6x" represents the "after" 6 characters of the location where the cursor was deleted.

"x": Uppercase X, each time it is pressed, deletes the "front" character at the location of the cursor.

"#X": for example, "20x" represents the "front" 20 characters of the location where the cursor was deleted.

"dd": Delete the line where the cursor is located.

"#dd": Deletes the # line starting at the line where the cursor is located

5). Copy

"yw": Copies the characters from the cursor to the end of the word into the buffer.

"#yw": Copy # words to Buffer

"yy": Copy cursor line to buffer.

"#yy": for example, "6yy" represents a copy of 6 lines of text from the line where the cursor is located.

"p": Paste the characters in the buffer to the cursor location. Note: All copy commands related to "Y" must be mated with "P" to complete the copy and paste function.

6). Replace

"r": Replaces the character at which the cursor is located.

"r": Replaces the character where the cursor is located until the "esc" key is pressed.

7). Reply to Last action

"u": If you mistakenly execute a command, you can press "u" immediately to go back to the previous action. Multiple replies can be performed by pressing "U" multiple times.

8). Change

"cw": Change the word-to-tail at the cursor location

"c#w": For example, "c3w" represents a change of 3 words

9). Jump to the specified line

"ctrl"+"g" lists the line number of the line where the cursor is located.

"#G": for example, "15g", which means moving the cursor to the beginning of the 15th line of the article.

4 last command about line mode

Before using "last line mode", remember to press "esc" to make sure you are under "command mode" and then press ":" Colon to enter "last line mode".

A) List line numbers

"set nu": After you enter "set nu", the line numbers are listed before each line in the file.

B) jump to a line in the file

The "#":"#" number represents a number, enter a number after the colon, and then press ENTER to jump to the line, such as entering the number 15, and then enter, you will jump to the 15th line of the article.

C) Find characters

"/Keyword: First press the"/"key, and then enter the character you want to look for, if the first keyword is not what you want, you can always press"n"will look back to the keyword you want.

"? keyword": Press "?" first Key, and then enter the character you want to find, if the first keyword is not what you want, you can always press "n" will look forward to the keyword you want.

D) Save the file

"w": Enter the letter "w" the colon to save the file.

E) Leave VI

"q": Press "q" is to exit, if you cannot leave VI, can be "q" followed by a "!" Forced to leave VI.

"wq": Generally recommended to leave, use with "w", so you can also save the file when exiting.

5 VI Command List

1. The following table lists the functions of some keys in the command mode:

H

Move left cursor one character

L

Move the cursor one character to the right

K

Move the cursor up one line

J

Move the cursor down one line

^

Cursor moves to the beginning of the line

0

Number "0", the cursor moves to the beginning of the article

G

Cursor moves to the end of the article

$

Move cursor to end of line

Ctrl+f

Flip the screen forward

Ctrl+b

Flip the screen backwards

Ctrl+d

Turn Half-screen forward

Ctrl+u

Turn Back half screen

I

Insert a character before the cursor position

A

The next character at the cursor position begins to increment

O

Insert a new row, starting at the beginning of the line

Esc

Fallback from input state to command state

X

Delete the character following the cursor

X

# characters after the cursor is deleted

X

(uppercase x), delete the character in front of the cursor

X

Delete the # characters before the cursor

Dd

Delete the line where the cursor is located

Dd

Remove the # line from the number of lines that the cursor contains

yw

Copy a word where the cursor is located

yw

Copy the # Word where the cursor is located

Yy

Copy a row where the cursor is located

Yy

Copy the # line from the number of lines where the cursor is located

P

Paste

U

Cancel operation

cw

Change a word in the position of your cursor

cw

Change the # Word where the cursor is located

2, the following table lists some instructions in the line command mode

W filename

Save the file you are editing as filename

WQ filename

Save the file being edited as filename and exit VI

Q!

Discard all changes, exit VI

Set Nu

Show line Numbers

Or?

Find, enter what you are looking for in/after

N

with/or, if the search is not the keyword you are looking for, press N or backwards (with/to) or forward (with?) to continue looking until you find it.

For the first use VI, there are a few notes to remind:

1. When you open a file with VI, you are in command mode, and you want to switch to insert mode to enter text. Toggle method: Click on the letter "i" "Command mode" to enter "Insert Mode", then you can start to enter the text.
2, after editing, you need to switch from insert mode to command line mode in order to save the file, switch method: Press the "esc" key.

3. Save and exit the file: Enter in command mode: WQ! (Don't forget to wq the front:)

[Turn]linux under the terminal common commands and the VI command to modify the file and save the use method