Summary of the second week learning process

1. Key points of knowledge carding:

Four Steps for GCC compilation: preprocessing (GCC-E), compiling (gcc-s), Assembly (GCC-C), linking

Static link library generation: ar rcsv libxxx.a xxx.o

Generated gcc-fpic-c xxx.c for shared libraries

Fast Memory

Vim:

VIM has 6 basic modes and 5 derivation modes, and here we simply introduce the next 6 basic modes:

• Normal mode

• Insertion modes (insert mode)

• Visual modes (visual mode)

• Selection mode (select modes)

• Command line mode

• Ex modes (ex mode)

Three common modes of switching:

Vim starts into normal mode, in insert mode or command line mode only need to press ESC or ctrl+[(this is not used in the VIM course environment) to enter the normal mode. In normal mode , press I (insert) or A (attach) key to enter the insert mode, in normal mode press : Enter command line mode. Enter WQ in the command line mode to save and exit Vim.

Several shortcut keys:

• The uppercase "K" can be used to find help for the function: Look at the man page, in command mode, place the cursor on the function name, press "K" to see the mans page directly.
• Several settings

: Set NU Displays line number

: Set AI automatically indents rows

: Set ts=4 sets a TAB key equal to several spaces

• Move cursor

[[Go to Previous ' {' in first column]

]] to go to the next "{" In the first column

{Go to previous empty row

} go to the next empty line

GD goes to the definition of the local variable that the current cursor refers to.

into Vim:

(1) Use the VIM command to enter VIM:

Vim is appended with the file name that you want to open, or that does not exist (then as a new file). Open the Xfce terminal and enter the following command

$ vim practice_1.txt

Vim editor can also be opened using Vim directly, but no files will be opened.

$ vim

Enter the command line mode and the :e 文件路径 same file can be opened.

(2) Cursor movement

After entering Vim, press the i key to enter insert mode. In this mode you can enter text information below, please enter the following three lines of information:

12345678abcdefghijkshiyanlou.com

Press Esc Enter normal mode, use the arrow keys in this mode or,,, the h j k l Key can move the cursor.

Key	Description
h	Left
l	Right (lowercase L)
j	Under
k	On
w	Move to the next word
b	Move to the previous word

Try using the arrow keys to move the cursor over these letters in normal mode shiyanlou .

(3) Insert mode

Use the following key in normal mode to enter insert mode, and to start typing from the corresponding position

Command	Description
i	Edit at current cursor
I	Insert at beginning of line
A	Inserting at the end of a row
a	Insert an edit after the cursor
o	Insert a new row after the current row
O	Insert a new row before the current line
cw	Replace the character from the position of the cursor to the end of a word

Try different ways to get into the insert mode from normal mode, add in front of the last line Shiyanlou www. , Notice that each time you go back to normal mode to switch to insert mode in different ways

(4) Save the document

Enter the : command line mode from normal mode, enter w a carriage return, and save the document. Enter to save the :w 文件名 document as a different file name or under another path.

(5) Exit

Enter : command line mode from normal mode, enter wq return, save and exit edit

Here are a few other ways to exit:

Command	Description
:q!	Force quit, do not save
:q	Exit
:wq!	Force Save and exit
:w <文件路径>	Save As
:saveas 文件路径	Save As
:x	Save and exit
:wq	Save and exit

Normal mode input Shift+zz can be saved out of vim

(6) Delete

Go to normal mode and use the following commands to quickly delete text:

Command	Description
x	Delete the character that the cursor contains
X	Delete the previous character of a cursor
Delete	Withx
dd	Delete entire row
dw	Delete a word (not in Chinese)
d$OrD	Delete to end of line
d^	Delete to beginning of line
dG	Delete to end of document
d1G	Delete to document header

In addition, you can add a number to the command before it, indicating that multiple rows are deleted at once, such as:

2ddRepresents delete 2 at a time.

Gcc

We can divide the compilation process into four steps:

• Preprocessing: Gcc–e hello.c–o hello.i;gcc–e Call CPP
• Compilation: Gcc–s hello.i–o hello.s;gcc–s Call CCL
• Compilation: Gcc–c hello.s–o hello.o;gcc-c Call as
• Link: gcc hello.o–o hello; gcc-o call ld

Gdb

The most basic commands of GDB are:

• GdB Programm (Start gdb)
• B Set Breakpoints (4 breakpoints are set: Line breakpoint, function breakpoint, conditional breakpoint, temporary breakpoint)
• Run starts running the program
• BT Print function Call stack
• P View variable values
• C continue running from the current breakpoint to the next breakpoint
• N Single Step operation
• S Single Step operation
• Quit Quit GDB

Debug command:

• Change of display tracking variable value
• Until jump out of the loop
• Finish Jump function
• Help

2. Detailed Introduction

Vim repeating command repeatedly executes last command

In normal mode . (decimal point) means the last command operation is repeated

Copy test files to a local directory

$ cp /etc/protocols .

Open a file for editing

$ vim protocols

Normal mode input x , delete the first character, the input . (decimal point) will be deleted again a character, in addition to also can be repeated dd delete operation

Execute commands of the same number of times

Enter Normal mode input N<command> , n indicates the number of repetitions, and the following is the practice:

In normal mode, you can also dw daw delete a word with or (delete a word), so you can easily associate (n with the dnw corresponding number ) to delete n words

Quick Jump for Cursors

In normal mode, the following command allows the cursor to be quickly reversed to the specified position, we discuss the rapid implementation of the inline jump and in-line jump

Inline jump

Command	Description
nG(n shift+g)	Cursor moves to nth row (if no line number is displayed by default, enter command mode first :set nu to display line numbers)
gg	Cursor moves to the first row
G(SHIFT+G)	To the last line

tip: After you have completed the jump, you can use the Ctrl+o quick to go back to the previous (before the jump) cursor position , this technique is very practical, such as when you write code, suddenly think of a bug, need to change, this time you jump over to change, just need to press Ctrl+o You can go back to where you were before. Vim will be waiting for you to explore with a lot of similar tips.

In-line jump

In normal mode, use the following command to jump within a line in a word

Command	Description
w	To the beginning of the next word
e	To the end of the next word
b	To the beginning of the first word
ge	To the end of the previous word
0Or^	to the wardrobe.
$	To end of line
f<字母>	Search backwards < letters > and jump to the first matching position (very useful)
F<字母>	Search forward < letters > and jump to the first matching position
t<字母>	Search backwards < letters > and jump to a letter before the first matching position (not used)
T<字母>	Search forward < letter > and jump to a letter after the first matching position (not used)

Do the following exercises in turn:

• In normal mode, jump to a line, use w jump to the beginning of a word, and then use dw the word delete
• In normal mode, use e jump to the end of a word and use ~ the letter that contains the cursor to capitalize or lower case

Copy paste and Cut Copy and paste text

• Use replication in normal mode y

  • In normal mode, yy the entire line where the cursor is copied ( 3yy representing the replication of 3 rows)
  • In normal mode, y^ copy to the beginning of the line, or y0 . Does not contain the character at which the cursor is located.
  • In normal mode, y$ copy to end of line. The character where the light is contained.
  • In normal mode, yw copy a word.
  • In normal mode, y2w copy two words.
  • In normal mode, yG copy to the end of the text.
  • In normal mode, y1G copy to the beginning of the text.

• Use paste in normal mode p

  • In normal mode, p (lowercase) represents pasting to the cursor (bottom)
  • In normal mode, P (uppercase) means pasting to the front of the cursor (top)

Open the file into normal mode practice the above command, you can now feel free yy to

$ vim protocols

Cut and paste

In fact, the dd deletion of the command is cut, each time you dd delete the contents of the document can be used p to paste, also this allows us to achieve a very refreshing function-exchange up and down line:

ddp, so simple, that it implements the fast Exchange cursor where the line is with the line below it

Experiment experience: familiar with the command. In normal mode. (decimal point) indicates that the last command operation was repeated. For example: Enter x in normal mode, delete the first character, enter. (The decimal point) will delete one character again, or you can repeat the deletion of the DD. NG (n shift+g) GG g (shift+g) Ctrl+o, if a bug needs to be modified, simply press Ctrl+o to return to the previous position.

Substitution and revocation of characters (undo action) Replace and undo (undo) commands

Both the Replace and undo commands are for normal mode operations

Command	Description
r+< to replace letters >	Replace the letter that contains the cursor with the specified letter
R	Continuous replacement until you press theEsc
cc	Replace the entire row, which deletes the row of the cursor and enters insert mode
cw	Replace a word, delete a word, and enter insert mode
CUppercase	Replace cursor later to end of line
~	Reverses the case of a cursor in the same letter
uN	Undo One or N operations
UUppercase	Undo all changes to the current line
Ctrl+r	Redo, that is, undo undo operation

To open a file for editing:

$ vim practice_2# 输入以下文本www.shiyanlou.com

Then do the following:

• Input 11G , jump to 11 lines
• Enter FA to jump to the first a character
• Input r , and the input b,a character is replaced by the B character (practical)
• Enter a R replacement character, enter a new string, press ESC to return to normal mode (useful)
• Enter cc replace whole line character, enter new string, press ESC to return to normal mode after entering
• Enter cw replace one English word (word), press ESC to return to normal mode (useful)
• Input ~ , the case of the character in which the rollover cursor is located
• The input is C replaced with the end of the line, that is, the word will be replaced after the cursor is in place, press ESC to return to normal mode
• Enter u undo Last action

Quick indent using commands for quick-adjust indent operations

This section learns how to indent quickly in vim and indent operations are effective in normal mode

Open a file for editing

$ vim protocols

• Normal mode input 15G , jump to 15 lines
• Input entire line in normal mode >> indent right (used to format code super cool)
• Enter the entire line in normal mode to the << left fallback
• Normal mode enter : command line mode to shiftwidth set values to control the number of characters for indentation and fallback

Shiftwidth command

shiftwidthThe command refers >> to the indentation generated by the previous command (which can be abbreviated sw ). Enter : command line mode to set values in normal mode to control the number of characters in shiftwidth indentation and fallback get current setpoint

:set shiftwidth?

Set indent to 10 characters

:set shiftwidth=10

Enter ESC back into normal mode and try again to >> see if the indent changes

Adjust text position

Command line mode enter :ce (center) command to center the contents of the bank

:ce

Command line mode enter :ri (right) command to make our text

:ri

Command line Mode enter: le (left) command to leave the contents of the bank

:le

Find Quick Find

Enter Normal mode / and then type the string you want to find and press ENTER to find it. ？is the same as the / function, but ？ looks up and / down. After entering the lookup, the input n and N can continue to find n the expression to continue the lookup, N reverse Lookup

Advanced Find

• Enter \* a word in normal mode to find where the cursor is located
• Normal mode input \# Ibid, but \* forward (up) to find, #则是向后 (bottom) find
• Normal mode g\* \* , but partially matches the word
• Normal mode g\# \# , but partially matches the word

n N The Continue find command for the above lookup is still available.

Experimental experience: Learn to execute commands of the same number of times, replace and Undo commands are for normal mode operation
Command r+< to replace the letter > R cc Description replace the letter with the specified letter with the word, until you press ESC to replace the entire row, deleting the row of the cursor and entering insert mode.

Multi-file editing using Vim to edit multiple files

There are two forms of editing multiple files, one being a parameter that is used before entering Vim is multiple files. Another is to enter vim and then edit the other files. Create two new files and edit them simultaneously

$ vim 1.txt 2.txt

Default Access 1.txt to file editing interface

• Command line mode input :n edit 2.txt file, you can ! :n! Force switch, the input of a file is not saved, just switch to another file
• Command line mode input :N edit 1.txt file, can be ! forced to :N! switch, the input in the previous file is not saved, just switch to another file

Open new file after entering vim

• Command line mode enter :e 3.txt open new file 3.txt
• Command line mode input :e# back to the previous file
• command-line mode input :ls to list previously edited documents
• Command line mode input :b 2.txt (or number) can be directly into the file 2.txt edit
• Enter :bd 2.txt (or number) in command-line mode to delete a file item from a previously edited list
• Command line mode input :e! 4.txt , new open file 4.txt, discard the file being edited
• Enter :f The file name you are editing in command line mode
• Input in command line mode :f new.txt , change the file being edited name to New.txt

Recover files

If the document is not saved due to a power outage, you can use the recovery method, enter the vim -r document, input :ewcover 1.txt to restore

$ vim -r 1.txt

Introduction to Visual mode Visual mode commands

• Enter in normal mode v (lowercase), enter the character selection mode, you can move the cursor, where the cursor will be selected. The selection is deselected when the V-meeting is pressed again.
• In normal mode input Shift+v (lowercase), enter the line selection mode, press V will be the entire row selection, you can move up and down the cursor select more rows, again, press once Shift+v can be deselected.
• In normal mode Ctrl+v (lowercase), this is the area selection mode, you can select the rectangular region, and then cancel the selection by one time Ctrl+v .
• Enter d Delete selection area in normal mode
• Enter y Copy selection area contents in normal mode

Introduction to Windows Operation window operation

Vim can open multiple windows in one interface for editing, which are called Vim windows. There are many ways to open a method, for example, you can use the command line mode input to :new open a new Vim window, and enter the window to edit a new file (Normal mode Ctrl+w can also be entered, but Ctrl+w in Chrome will be closed tab page with Chrome shortcut keys conflict, So with this shortcut you can practice in IE or other browsers, in addition to the :new command, the following list of methods can also be used in command mode or Normal mode to open a new window:

• Command-line mode enter :sp 1.txt open new Landscape window to edit 1.txt
• Command-line mode :vsp 2.txt to open a new vertical window to edit 1.txt
• Ctrl-w ssplit the current window into two horizontal windows in normal mode
• Ctrl-w vsplit the current window into two vertical windows in normal mode
• In normal mode Ctrl-w q , it is: Q ends the split window. If you have input in a new window, you need to use the mandatory character! namely: q!
• Ctrl-w oOpen a window in normal mode and hide all previous windows
• Ctrl-w jmove to the following window in normal mode
• Ctrl-w kmove to the upper window in normal mode
• Ctrl-w hmove to the left window in normal mode
• Ctrl-w lmove to the right window in normal mode
• Ctrl-w Jmove the current window below in normal mode
• Ctrl-w Kmove the current window to the top in normal mode
• Ctrl-w Hmove the current window to the left in normal mode
• Ctrl-w Lmove the current window to the right in normal mode
• Ctrl-w -reduce the height of the window in normal mode
• Ctrl-w +increase the height of the window in normal mode

Windows Operation exercises

• command-line mode input :new open a new vim window
• Command-line mode enter :sp 2.txt open new Landscape window to edit 2.txt
• Command-line mode enter :vsp 3.txt open new Landscape window to edit 3.txt
• If you use a non-Chrome browser, you can use Ctrl+w the jump between windows
• Enter :q! exit multi-window editing in command-line mode of different windows

Document encryption create an encrypted document

$ vim -x file1

Enter your password to confirm the password so that the next time you open, VIM will ask you to enter the password

Executing external commands in vim

Enter command-line mode ! to execute external shell commands

• :!lsUsed to display the contents of the current directory
• :!rm FILENAMEUsed to delete a file named filename
• :w FILENAMESave the file you are editing in the current VIM as a filename file

Help system vim in view Help

• Press F1 vim to open your own preset help document in normal mode
• Enter :h shiftwidth shiftwidth The open Help file in command line mode
• Input :ver display version and parameters in command line mode

Function setting Vim's function setting

Can be set when editing the file function settings, such as the command line mode input :set nu (display number of lines), set value exit Vim will not be saved. To permanently save the configuration, you need to modify the Vim configuration file. Vim configuration file ~/.vimrc , you can open the file for modification, but be careful not to affect the normal use of vim

Get the current settings

• Enter :set or :se display all modified configurations in command line mode
• command-line mode input :set all displays all the SetPoint values
• Command-line mode :set option? to enter a setting value that displays option
• Command line mode to enter the :set nooption cancel current set value

Description of the Set function

• :set autoindent(ai)automatic indentation of input settings in command line mode
• Command line mode input :set autowrite(aw) set AutoArchive, default not open
• Enter or in command line :set background=dark mode light , set the background style
• Command line mode input :set backup(bk) set automatic backup, default not open
• Command line mode input : set cindent(cin) set C language style indent

3. Questions and Answers

1. When using "x" to delete the character at the cursor location, the character is deleted by mistake and will not be recalled.

Use the U key to undo.

2. Problem: GDB's n (next) command lets GDB execute the next line and then pause. The s (step) command acts like this, except that the step command enters the function when the function is called, so what should be preferred in actual use? Why?

Next is a single-step tracker that does not enter the function body when it encounters a function call, and step encounters a user-defined function that steps into the function to run, and next calls the function directly, not into the function body.

Step command, if there is a function call on the source line on which the step command will run, then the Step command causes GDB to enter the inside of the called function.

3. Some pairs of commands can not be clearly remembered, resulting in wasting a lot of time, such as F and F,? and/

Multiple memories, repetitive exercises

Summary of the second week learning process