Linux C Programming (1) VIM and GCC commands

1. Enter the following command to start VI:

      (1) VI: Do not specify a file name, you will need to specify a filename when saving it.       (2) VI file name: The file can be either existing or new.       (3) vi +n file name: Enter VI, the cursor stops at the beginning of the nth line.       (4) vi + file name: Enter VI, the cursor stops at the beginning of the last line of the file.       (4) vi +/string file name: Enter VI, the cursor stops at the first string where the row. 2. Save the file in VI and exit:      (1) W file name: Saves the contents of the current file in a new file specified by "file name" and generates an error if the file already exists.       (2) w! File name: Saves the contents of the current file in a new file specified by file name, overwriting the original file if it already exists. 3. Cursor Movement:      (1) NW: Right shift n words, n is a number, the cursor is at the top of the nth word.       (2) W: move 1 words to the right, and the cursor is at the beginning of the next word.       (3) NB: Shift left n characters, n is number, and the cursor is at the top of the nth word.       (4) B: Move left 1 words, the cursor is at the beginning of the next word.       (5) (: Move to the beginning of the sentence, if you are already at the beginning of the sentence, move to the beginning of the previous sentence.)       (6)): Move the first sentence of the next sentence.       (7) {: Move to the beginning of paragraph of this paragraph, if it is already in the beginning of the paragraph, move to the beginning of the previous paragraph.       (8) 1G: Move to the beginning of the first voyage of the file; G: Move to the beginning of the last line of the file; NG: Moves to the beginning of the nth row of the file.       (9) <ctrl>+g: reports where the cursor is located. 4. Deletion of the text:      (1) DW: Delete A word in the clerical position of the cursor; NDW: Deletes the n characters from the beginning of the cursor.       (2) DB: Deletes a word before the cursor; NDB: Deletes the first n characters from the cursor.   &NBSP;   (3) D0: Removes all characters from the previous character to the beginning of the cursor.       (4) d$: Removes all characters from the cursor to the end of the line.       (5) d (: Removes all characters from the beginning of the current character to the first sentence.       (6) d): Removes all characters from the beginning of the current period character to the end of a sentence.       (7) d{: Removes all characters from the beginning of the current character to the top of the paragraph.       (8) d}: Removes all characters from the beginning of the current character to the short tail. 5. Text find and replace:      (1)? String<enter>: Find string       (2): s/old/new: Replace old with new in the current line and replace it only once.       (3): s/old/new/g: Replace old  with new in current line     (4): 1,10s/old/new/g: Replace old  with new on 1~10 line     (5): 1, $s/old/new/g: replace Old6 with new in the entire file. Copy and paste text       (1) YW: Copy the character from the cursor position to the end of the word into the buffer       (2) NYW: Copies the n characters starting at the cursor position into the buffer     & nbsp; (3) YB: Copy a WORD from the cursor to the left       (4) NYB: Copy n characters from the cursor to the left       (5) y0: Copy all characters from the previous character of the cursor to the beginning of the start   & nbsp   (6) y$: Copy all characters from the beginning of the cursor to the end of the line       (7) NP: Inserts the copied text after the cursor position, replicates n times       (8) NP: Inserts the copied text in front of the cursor position, replicating n times. 7. Naming rules for variables under Linux:      (1) Variable names must be meaningful and accurate;      (2) not recommended for case mixing;      (3) in case of loss of meaning, try to use a shorter variable name.       (4) The type of the variable is not represented by the Hungarian nomenclature.       (5) The function name should begin with a verb because the function is a set of statement blocks with a specific function;      (6) Avoid using global variable  8 as much as possible. The GCC compiler can be divided into 4 stages:      (1) preprocessing (pre-processing)       pre-processing stage, input C language source files, usually *.c, mainly processing #ifdef, # Include and # define preprocessing commands. This phase typically generates an intermediate file *.i. The command is:    &NBSP;GCC-E test.c-o test.i      (2) compilation (compling)       During the compile phase, the intermediate file is entered *.I , build assembly language file *.s after compiling. The command is:     gcc-s test.i-o test.s      (3) assembly (assembling)       in the assembly phase, the input assembly file * . s converted to binary machine code *.O, whose commands are:     gcc-c test.s-o test.o      (4) Link (linking)       in link Stage the input binary machine code file *.S with other machine code files and library files into an executable binary code file with commands:    &NBSP;GCC test.o-o test      Finally, the executable file test is generated.       can be simplified to: gcc test.c-o test9. GCC compiles multiple source files with the command:     gcc-o test testmain.c other1.c other2.c      The command compiles 3 source files at the same time, and finallyGenerates an executable program test.       NOTE: When generating an executable program, a program must have only one main function in all compiled and connected source files, whether it is a single source file or multiple source files. Options for GCC:      (1)-C: Compile only, do not link to executable file, compiler only generated by input. C as suffix source code file. O is the suffix of the target file, usually used to compile a subroutine file that does not contain the main program.       (2)-G: Generate the symbolic information necessary for the debugger gdb, to debug the source code, you must include this option when compiling the program.       (3)-O: Optimize the program to compile, link, the resulting executable file execution efficiency is high, but in the compilation, link speed is correspondingly slower.       (4)-o2: Better than-O to optimize compilation, linking.       (5)-wall: Output all warning messages       (6)-W: Turn off all warnings, we recommend not using       (7)- Idirname: Add a directory named DirName to the program header file directory list       (8)-ldirname: Adds a directory named DirName to the library file search directory list of the program, which is the parameter used in the link process.       (9)-lname: Instructs the compiler to mount a function library named Libname.a at link time, which is located in a predefined directory of the system or a directory specified by the-l option. One. GCC error types and Countermeasures       (1) C syntax errors       (2) header file or library file errors       (3) undefined symbol 12. strcpy is insecure and has a security vulnerability, so you should generally use STRNCPY,STRCAT and strncat as well. Strstr is looking for the first occurrence of S2 from the string s1, returns a pointer to the first occurrence of the S2 position, and returns null if not found. STRCHR finds the position of the first occurrence of the character C in the string s, returns the first occurrence of the character C pointer, and returns NULL if there is no C in S.

Linux C Programming (1) VIM and GCC commands