1. 关于我
个人信息
Jick Nan |
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2. C
2.1. Coding Style
先看 [http://lxr.linux.no/source/Documentation/CodingStyle Linux kernel coding style]
2.1.1. Indentation
- 8-char indent
- If you need more than 3 levels of indentation, you're screwed anyway, and should fix your program.
- Don't put multiple statements on a single line unless you have something to hide.
- Get a decent editor, and don't leave whitespace at the end of lines.
2.1.2. Breaking long lines and strings
- Coding style is all about readability and maintainabilty using commonly avaible tools.
- The limit on the length of lines is 80 colums and this is a hard limit.
2.1.3. Placing braces
- The preferred way, as shown to us by the prophets Kernighan and Ritchie, is to put the opening brace last on the line, and put the closing brace first.
- namely function have the opening brace at the begining of the next line.
2.1.4. Naming
- C is a Spartan language, and so should your naming be.
- GLOBAL variables (to be used only if you _really_need them) need to have descriptive name, as do global functions.
- LOCAL variable name should be short, and to the point.
2.1.5. Fuctions
- Fuctions should be short and sweet, and do just one thind.
- Another measure of the functions is the number of local variables, They shouldn't exceed 5-10, or you're doing something wrong.
2.1.6. Centralized exiting of functions
- About gogo statement.
2.1.7. Commenting
- Comments are good, but there is also a demage of over-commenting.
- Generally, you want your comments to tell WHAT your code does, not HOW.
2.1.8. You've made a mess of it
- About GNU Emacs and GNU indent.
- 'indent' is not a fix for bad programing.
2.1.9. Data structures
- Data structures that have visibility outside the single-threaded environment they are created and destoryed in should always have reference counts.
- Locking is _not_ a replacement for reference counting.
- If another thread can find your data structure, and you don't have a reference count on it, you almost certainly have a bug.
2.1.10. Macros, Enums, Inline functions and RTL
- Names of macros defining contants and labels in enums are capitalized.
- Enums are preferred when defining serval related constants.
- Generally, inline functions are preferable to macros resembling functions.
- Macros with multiple statements should be enclosed in a do-while block.
2.2. malloc, calloc, free
- 一个严重的错误：释放不是通过调用 malloc, calloc 得到的指针所指向的存储空间。
- 使用已释放空间同样是错误的。
3. GNU Tools
3.1. GCC
- ./configure --target=arm-elf --prefix=/opt/gcc-3.4.6-arm
3.2. Vim
先看 [http://chinaunix.net/jh/28/194152.html 进行有效编辑的七种习惯] by Bram Moolenaar, the author of vim.
再看 [http://www-128.ibm.com/developerworks/cn/linux/l-tip-vim1/ Vim 实用技术] at DeveloperWorks.
- vim7 config
- ./configure --with-features=huge --enable-cscope --enable-multibyte --enable-xim --enable-fontset --enable-gui=gnome2
3.2.1. Edit a file
3.2.1.1. Move around quickly
If you set the incsearch option, Vim will show the first match for the pattern, while you are still typing it. This quickly shows a typo in the pattern.
If you set hlsearch option, Vim will highlight all matches for the pattern with a yellow background. :nohlsearch will close it.
If you see a specific word and want to search for other occurrences of the same word, use the * command to grab the word from under the cursor and search for the next one, while # search for the previous one.
- In structured text(C/C++)
% can jump to many different matching items. It is very useful to check if() and {} constructs are balanced properly.
Use [{ to jump back to the "{" at the start of the current code block, and ]} for '}'.
Use gd to jump from the use of variable to its local declaration.
可视（visual）模式，用于选定文本块；可以在正常模式下输入v（小写）来按字符选定，输入V（大写）来按行选定，或输入Ctrl-V来按方块选定。
`.（跳转到最近修改过的位置）
ZQ（无条件退出）
ZZ（存盘退出）
ga（显示光标下的字符在当前使用的 encoding 下的内码）
guw（光标下的单词变为小写）
gUw（光标下的单词变为大写）
:TOhtml （根据 Vim 的语法加亮的方式生成 HTML 代码）
K （显示光标下单词的 man 手册页）
将当前行提到页首：zt，页尾：zb。
gg 定位到文件开头，G 定位到文件的结尾。
3.2.1.2. Don't type it twice
If you want to change one word into another in the whole file, you can use the :s(substitute) command.
去掉所有的行尾空格：“:%s/\s\+$//”。
去掉所有的空白行：“:%s/\(\s*\n\)\+/\r/”。
去掉所有的“//”注释：“:%s!\s*//.*!!”。
去掉所有的“/* */”注释：“:%s!\s*/\*\_.\{-}\*/\s*! !g”。
If you want to change one word into another only a few locations, a quick method is to use the * command to find the next occurrence of the word and use cw to change the word. Then type n to find the next word and .(dot) to repeat the cw command.
CTRL-N can auto complete function and variable names. Vim looks up words in the file you are editing, and also in #include'd files.
Vim has a mechanism to record a macro. You type qa to start recording into register 'a'. Then you type your commands as usual and finally hit q again to stop recording. When you want to repeat the recorded commands you type @a.
- 寄存器
- 除了有一个无名寄存器外，Vim 还有一大堆有名的寄存器，可以通过“"”（参见“:help "”）或“Ctrl-R”（参见“:help i_CTRL-R”和“:help c_CTRL-R”）加寄存器名（字母、数字和某些特殊字符，参见“:help registers”；“无名”寄存器的名字是“"”）来访问。比如，你先使用“"ayy”复制了一行，然后使用“dd”删掉了一行，然后移动光标到要复制到的位置，就可以使用“"aP”把先前复制的内容粘贴上去了。
- 在使用 X Window 系统时，有两个特殊的寄存器是需要注意一下的：“"*”访问的寄存器是 X 的主选择区域（primary selection），“"+”访问的寄存器是 X 的剪贴板（clipboard）。
- 还有一个很特殊的“寄存器”：“=”。在插入模式或命令模式中，键入“Ctrl-R=”，Vim 会提示你输入一个表达式，普通的整数运算在此完全有效。
3.2.1.3. Fix it when it's wrong
It's normal to make errors while typing, this can be corrected with abbreviations: :abbr Lunix Linux.
The same mechanism can be used to type a long word with just a few characters: :abbr pn pinguin.
- To find errors in your text Vim has a clever hightlighting mechanism. This was actually meant to be used to do syntax hightlighting of programs, but it can catch and highlight errors as well.
Modeline for C coding style(see above): /* vim:shiftwidth=8:tabstop=8:filetype=c:norl: */
把光标移到要重新格式化的文本开头，使用gq命令后面跟一个光标移动命令确定重新格式化的范围。比如gq}（格式化一段），gq5j（格式化 5 行），gqG（格式化至文件末尾）。
:set list 查看所有不可见字符; :set nolist 关闭
- A more complex example: English text.
3.2.2. Edit more files
3.2.2.1. A file seldom comes alone
- Tag mechanism works for jumping between files.
- :tag 关键字（跳转到与“关键字”匹配的标记处）
- :tselect [关键字]（显示与“关键字”匹配的标记列表，输入数字跳转到指定的标记）
- :tjump [关键字]（类似于“:tselect”，但当匹配项只有一个时直接跳转至标记处而不再显示列表）
- :tn（跳转到下一个匹配的标记处）
- :tp（跳转到上一个匹配的标记处）
- Ctrl-]（跳转到与光标下的关键字匹配的标记处；除“关键字”直接从光标位置自动获得外，功能与“:tags”相同）
- g]（与“Ctrl-]”功能类似，但使用的命令是“:tselect”）
- g Ctrl-]（与“Ctrl-]”功能类似，但使用的命令是“:tjump”）
- Ctrl-T（跳转回上次使用以上命令跳转前的位置）
Another powerful mechanism is to find all occurrences of a name in a group of files, using the :grep command. Vim makes a list of all matches, and jumps to the first one. The :cn command takes you to each next match.
Positions the cursor on the name of the function in your file and type [i: Vim will show a list of all matches for the function name in the included files.
- In vim you can split the text erea in several parts to edit different files.
:split 上下分屏； :vsplit 左右分屏。
- There are more uses of multiple window. The preview-tag mechanism is a very good example.
- 可以使用“gf”命令方便地跳转到光标下的文件名所代表的文件中。使用“Ctrl-O”（参见“:help CTRL-O”）可返回到原先的文件中。
3.2.2.2. Let's work together
Select some structured text in a list and sort it: !sort.
- 如果想把外部命令执行的结果插入到当前编辑的缓冲区中，可以考虑使用“:r!”。
当使用可视模式选中文本行后然后键入“:!”（命令行上将出现“:'<,'>!”，表示命令的范围是选定的文本），或者使用“:%!”（表示命令的范围是整个缓冲区中的文本），Vim 在执行后面的命令时，将把命令范围里的文本行作为后面执行的命令标准输入，并用命令执行后的标准输出替换当前缓冲区中的这些文本行。
- 要对所有的非空行进行编号，只需要“:%!nl”；要对包含空行的所有行进行编号？OK，“:%!nl -ba”。
3.2.2.3. Text is structured
One of the simpler things is to speed up the edit-compile-fix cycle. Vim has the :make command, which starts your compilations, catches the errors it produces and lets you jump to the error locations to fix the problems.
- :cn（显示下一个错误）
- :cp（显示上一个错误）
- :cl（列出所有的错误及其编号）
- :cc（跳转到指定编号的错误）
- :copen（打开快速修订窗口，在其中显示所有错误，可在错误上双击鼠标或按回车键跳转至该错误）
3.2.3. Sharpen the saw
3.2.3.1. Make it a habit
- You need to learn new commands and turn them into a habit.
3.2.4. Task
3.2.4.1. Editing in hex mode
- vim -b NSLU2?_v23R29.bin
- :%!xxd
- When completed, :%!xxd -r
3.3. CVS
先看 [http://www.chedong.com/tech/cvs_card.html CVS使用手册] by Chedong.
4. File System
先看 [http://www.debian-administration.org/articles/388 Filesystems (ext3, reiser, xfs, jfs) comparison on Debian Etch].
4.1. Ext3
- 稳定，中庸
4.2. JFS
- JFS is the lowest CPU-usage FS.
4.3. ReiserFS
- It's the only filesystem that supports shrinking a filesystem now
- Nothing here will shake my own choice of ReiserFS for most general purpose filesystems, it has a good performance on real world benchmarks, and is the most mature of the journalling file systems presented.(simonw)
4.4. XFS
[http://www.madpenguin.org/cms/html/67/6045.html File System Design part 1: XFS]
Technical Specifications:
- Journaled 64-bit filesystem with guaranteed filesystem consistency.
- Online Administration: XFS supports filesystem growth for mounted volumes, allows filesystem "freeze" and "thaw" operations to support volume level snapshots, and provides an online file defragmentation utility.
- Quotas: XFS supports user and group quotas. XFS considers quota information as filesystem metadata and uses journaling to avoid the need for lengthy quota consistency checks after a crash.
- XFS supports the ACL semantics and interfaces described in the draft POSIX 1003.1e standard.
XFS appears to be the most appropriate filesystem to install on a file server for home or small-business needs :
- It uses the maximum capacity of your server hard disk(s)
- It's the quickest FS to create, mount and unmount
It's the quickest FS for operations on large files (>500MB)
- This FS gets a good place for operations on a large number of small to moderate-size files and directories
- It constitutes a good CPU vs time compromise for large directory listing or file search
5. Samba
5.1. CIFS 修改之主要目的
- 简化与精练 SMB 协议中一些比较混乱的部分
- 增加 unicode 支持
- 改善文件锁
- 支持硬连接
- 彻底消除对 NetBIOS 的依赖
- Linux 增强 SMB-Unix 非 Windows 的文件类型（如：符号连接）
6. Misc
6.1. Opera Browser
For Opera 9 Beta
- Multi-tab: Ctrl-t:new Ctrl-w:close '1':previous '2':forward Ctrl-Tab: switch
- Resize with only one key press, using '0', '9'
- Reopen with Ctrl-z
- Fastest speed
- Mouse Genust: don't used, but it's really cool!
- Content blocker
- Site preference
- F9: 激活快捷键。如在编辑区，需要先激活。
- Q: 上一个链接 A: 下一个链接 W: 上一个标题 S: 下一个标题 E: 上一句 D: 下一句
- Shift + ← ↑ → ↓ : 定位超链接
- Ctrl + L 聚焦到地址栏
- Z: 后退 X: 前进
- Ctrl + Enter 自动已保存的输入密码
- Ctrl + B: 打开剪贴板中的地址（不用聚焦到地址栏）Ctrl + shift + B: 在后台打开剪贴板中的地址
6.2. IRC channel
- irc.freenode.net
- #nslu2-general // for end-user
- #nslu2-linux // for core development
- #openslug
7. 反馈
欢迎大家对我说三道四哪