《Linux程序设计第四版》读书笔记 - 第一章 入门

1. UNIX Philosophy:

Simplicity

Focus
Reusable Components
Filters
Open File Formats

2. Directories:

/bin: Binaries, programs used in booting the system
/usr/bin: User binaries, standard programs available to users
/usr/local/bin: Local binaries, programs specific to an installation
/opt: Optional operating system components and third-party applications

3. PATH variable is divided by ":", not ";"

4. gcc

-o    Name option that tells the compiler where to place the executable

-I     Specific header files in sub directories or nonstandard places

-l     Search a library by the given name, example, -lm is to find lib named "m", full file name is libm.a     

-L    Add search directory to compile

-c    Prevent the compiler from trying to create a complete program, only create object file *.o

5. ar     Create archive static library *.a

6. grep     example: grep exad *.h     Find all ".h" files which contain "exad" text 

7. Static library "*.a" will be copied when it is used by many applications, and it will consume large amount of memory and disk space; Share library can be arranged as a single copy, also it can be updated independently by naming libxxx.so.N, N is the version code.

8. Help "man" can show brief manual, "info" will show total manual.