【读书笔记0102】Beginning linux programming-3rd

Chapter 1: getting start
任何一本书都不可能适合任何人，这本书适合没有任何linux经验的C程序员
这章主要是介绍了unix linux gun的发展历史，
Unix is a trademark by The Open Group and source code belongs to SCO.
Unix phliosophy: The why we choose Unix.有点老掉牙的话题
这本书讲的却非常精辟：
1 what is Simplicity,
Small&simple in utilites
2 Focus,
It means,from the requirement ,we first break down the user needs.Then we try very small utilites which combined to perform. a single purpose so that easy to perform. and improve later for the better algorithms and interface.
3 Reusable,
To realize the reusable,you should have the ability to find out the core of your applications. then make it a lib.
And you should well documented with simple but flexible programming interface to helps others programmer.
4 Filters,
Filter is just transform. input and output ,to helps combining the programs.
5 Openfileformat
6 Flexibility:
is for the ingeniously users , never assume that user might want to do.
avoid arbitrary limits on field size,numbers limitation
Remember the famous name:AT&T,Linus Torvalds,Helsinki,Richard Stallman on GNU,Dennis Ritchie,
Programming Linux
1 Linux programs: two special typs: executables and scripts:
these two type can replace each other vice versa.
What the tips I learn form. this charpter:
1  / forward slash ,remember the UNIX got the first, the DOS not.
2  C compiler C89
3  emacs is a important editor in linux
4  ./  what that means
5  the RoadMap actually -- where the tools and development resources are located.
ok,这是个入门的重点：那就是知道linux是如何组织和应用各个应用和工具的： 默认路径，这个往往是初学者不知道的东西：
general applications: /usr/bin
administrator specific: /usr/local/bin  or /opt
usr/local will not remove while you reinstall the OS

You need to know the applications / include header files/ and the library files.
Some very useful flags for:
-I (uppercase letter for "i")  used for libs include path
-l (lowercase letter for "L")  find a lib's full path and name standard lib path. eg. -lm include a math libs in standard path
-L  add search directory , if not specify then it means just in current directory.
how to generate a lib and use
1 use -C while we compile the program:
2 use ar to creat a archive
then chapter said how a shared libraries are works
Getting helps show us the basic help method：
1 man
2 info
3 help  eg: used in bash shell:
help set