Michael's blog

2011-03-22T17:18:00.005+08:00

256 colors in VIM and xterm

For bourne shells (bash, zsh, pdksh) this is done in ~/.bashrc

if [ -e /lib/terminfo/x/xterm-256color ]; then
    export TERM='xterm-256color'
else
    export TERM='xterm-color'
fi

PS. 也許在X windows 下, 只要修改以下檔案, 不用修改~/.bashrc
1.
 Add following line in ~/.Xdefaults
    XTerm*termName: xterm-256color
2.
 ($ eval `dircolors ~/.coloursrc`)
 Add following line in ~/.coloursrc
    TERM xterm-256color

2011-03-15T10:14:00.005+08:00

VIM: Hightlighting with the match command.

The :match command specifies the name of a highlight group and a pattern. Any text matching the pattern will be displayed in the foreground and background colors defined by the highlight group. :help :match :help :2match

Some examples follow. These use a highlight group named ExtraWhitespace which could be defined with one of the following in your vimrc. :help :highlight

:highlight ExtraWhitespace ctermbg=red guibg=red
" The following alternative may be less obtrusive.
:highlight ExtraWhitespace ctermbg=darkgreen guibg=lightgreen
" Try the following if your GUI uses a dark background.
:highlight ExtraWhitespace ctermbg=darkgreen guibg=darkgreen

However, be aware that future colorscheme commands may clear all user-defined highlight groups. Using,

:autocmd ColorScheme * highlight ExtraWhitespace ctermbg=red guibg=red

before the first colorscheme command will ensure that the highlight group gets created and is not cleared by future colorscheme commands. :help :colorscheme

Once this highlight group is created, it can be associated with matching text as in the following examples.

" Show trailing whitespace:
:match ExtraWhitespace /\s\+$/

" Show trailing whitepace and spaces before a tab:
:match ExtraWhitespace /\s\+$\| \+\ze\t/

" Show tabs that are not at the start of a line:
:match ExtraWhitespace /[^\t]\zs\t\+/

" Show spaces used for indenting (so you use only tabs for indenting).
:match ExtraWhitespace /^\t*\zs \+/

" Switch off :match highlighting.
:match

Alternatively, the following pattern will match trailing whitespace, except when typing at the end of a line.

:match ExtraWhitespace /\s\+\%#\@ If you use this alternate pattern, you may want to consider using the following autocmd to let the highlighting show up as soon as you leave insert mode after entering trailing whitespace: 
 :autocmd InsertLeave * redraw!
 Or alternatively, the following can be used: 
 :au InsertEnter * match ExtraWhitespace /\s\+\%#\@ random[0]=0xff, random[1]=0xff

char random[2]
  --> random[0]=0xffffffff, random[1]=0xffffffff

2010-05-07T12:26:00.004+08:00

網路效能測試工具 - iperf

Server side:
# iperf -s

Client side:
# iperf -c 192.168.1.11 -t 30 -i 5 -f MBytes

-t, --time # time in seconds to transmit for (default 10 secs)
-i, --interval # seconds between periodic bandwidth reports
-f, --format [kmKM] format to report: Kbits, Mbits, KBytes, MBytes

2010-03-22T11:38:00.002+08:00

Welcome! My friend.
His name is "Polanshyh".

2010-03-22T11:34:00.002+08:00

Goodbye my good friend.

2010-03-04T15:07:00.001+08:00

又搞斷了一支。
太久沒練, 握力都退步了。

2010-02-12T15:34:00.006+08:00

新踏板到。
感謝維格換了一組新踏板給我。
(不過, 這是消費者基本的權利。也是保固該有的權利。)
框有加厚, 應該會比較耐用。
希望這組踏板可以陪我到下個一萬公里。

2010-02-11T12:07:00.008+08:00

用不到一年、騎不到1萬公里的踏板 xpedo MX-13 居然壞了 ~
真不耐操。
這是值 1500 元的踏板嗎?
輕量化真的跟堅固性成反比。

不過, 維格還不錯, 答應換一組新的給我。

2009-12-23T00:43:00.004+08:00

好用的 sscanf

int sscanf ( const char * str, const char * format, ...);

Read formatted data from string

Reads data from str and stores them according to the parameter format into the locations given by the additional arguments. Locations pointed by each additional argument are filled with their corresponding type of value specified in the format string.

Parameters

str

C string that the function processes as its source to retrieve the data.

format

C string that contains one or more of the following items:

Whitespace character: the function will read and ignore any whitespace characters (this includes blank spaces and the newline and tab characters) which are encountered before the next non-whitespace character. This includes any quantity of whitespace characters, or none.
Non-whitespace character, except percentage signs (%): Any character that is not either a whitespace character (blank, newline or tab) or part of a format specifier (which begin with a % character) causes the function to read the next character from str, compare it to this non-whitespace character and if it matches, it is discarded and the function continues with the next character of format and str. If the character does not match, the function fails and returns.
Format specifiers: A sequence formed by an initial percentage sign (%) indicates a format specifier, which is used to specify the type and format of the data to be retrieved from the str string and stored in the locations pointed by the additional arguments. A format specifier follows this prototype:

[=%[*][width][modifiers]type=]

where:

* An optional starting asterisk indicates that the data is to be retrieved from the str string but ignored, i.e. it is not stored in the corresponding argument.

width Specifies the maximum number of characters to be read in the current reading operation

modifiers Specifies a size different from int (in the case of d, i and n), unsigned int (in the case of o, u and x) or float (in the case of e, f and g) for the data pointed by the corresponding additional argument:
h : short int (for d, i and n), or unsigned short int (for o, u and x)
l : long int (for d, i and n), or unsigned long int (for o, u and x), or double (for e, f and g)
L : long double (for e, f and g)

type A character specifying the type of data to be read and how it is expected to be read. See next table.

fscanf type specifiers:
type Qualifying Input Type of argument

c Single character: Reads the next character. If a width different from 1 is specified, the function reads width characters and stores them in the successive locations of the array passed as argument. No null character is appended at the end. char *

d Decimal integer: Number optionally preceeded with a + or - sign. int *

e,E,f,g,G Floating point: Decimal number containing a decimal point, optionally preceeded by a + or - sign and optionally folowed by the e or E character and a decimal number. Two examples of valid entries are -732.103 and 7.12e4 float *

o Octal integer. int *

s String of characters. This will read subsequent characters until a whitespace is found (whitespace characters are considered to be blank, newline and tab). char *

u Unsigned decimal integer. unsigned int *

x,X Hexadecimal integer. int *

additional arguments

type	Qualifying Input	Type of argument
`c`	Single character: Reads the next character. If a width different from 1 is specified, the function reads width characters and stores them in the successive locations of the array passed as argument. No null character is appended at the end.	`char *`
`d`	Decimal integer: Number optionally preceeded with a `+` or `-` sign.	`int *`
`e`,`E`,`f`,`g`,`G`	Floating point: Decimal number containing a decimal point, optionally preceeded by a `+` or `-` sign and optionally folowed by the `e` or `E` character and a decimal number. Two examples of valid entries are -732.103 and 7.12e4	`float *`
`o`	Octal integer.	`int *`
`s`	String of characters. This will read subsequent characters until a whitespace is found (whitespace characters are considered to be blank, newline and tab).	`char *`
`u`	Unsigned decimal integer.	`unsigned int *`
`x`,`X`	Hexadecimal integer.	`int *`

The function expects a sequence of references as additional arguments, each one pointing to an object of the type specified by their corresponding %-tag within the format string, in the same order.
For each format specifier in the format string that retrieves data, an additional argument should be specified.
These arguments are expected to be references (pointers): if you want to store the result of a fscanf operation on a regular variable you should precede its identifier with the reference operator, i.e. an ampersand sign (&), like in:

int n; sscanf (str,"%d",&n);

Return Value

On success, the function returns the number of items succesfully read. This count can match the expected number of readings or fewer, even zero, if a matching failure happens.
In the case of an input failure before any data could be successfully read, EOF is returned.

Example

1 2 3 4 5 6 7 8 9 10 11 12 13 14

/* sscanf example */
#include 

int main ()
{
 char sentence []="Rudolph is 12 years old";
 char str [20];
 int i;

 sscanf (sentence,"%s %*s %d",str,&i);
 printf ("%s -> %d\n",str,i);

 return 0;
}

Output:
Rudolph -> 12

下列範例會示範如何使用 sscanf() C 執行階段函式來讀取分隔逗號 (，) 的欄位為內部緩衝區。索引鍵是使用中括號，sscanf() 函式的格式。格式會 %[^ '，'] 的告知函式讀取緩衝區，逗號 (，) 為止。

範例程式碼

/* The following sample illustrates the use of brackets and the
  caret (^) with sscanf().
  Compile options needed: none
*/

#include 
#include 
#include 

char *tokenstring = "first,25.5,second,15";
int result, i;
double fp;
char o[10], f[10], s[10], t[10];

void main()
{
  result = sscanf(tokenstring, "%[^','],%[^','],%[^','],%s", o, s, t, f);
  fp = atof(s);
  i  = atoi(f);
  printf("%s\n %lf\n %s\n %d\n", o, fp, t, i);
}

2009-04-14T10:33:00.009+08:00

看那四個黑點像什麼？

癢了好久的腳，今天終於找到了原兇：『跳蚤』。

有一隻母貓跑到了地下室生了幾隻小貓。跳蚤應該就是這麼被帶來的。
早上到地下室牽了我的腳踏車準備上班, 一出地下室發現褲管上怎麼一隻、隻的蟲蛇來蛇去，還有兩隻正附著在腳上, 捏死一看, 雖然沒看過跳蚤, 當下覺得應該就是跳蚤沒錯。
請同事拍了一張特寫, 雖然沒很清楚, 但放大還是可以穩約看出是跳蚤。

這應該是跳蚤沒錯吧？

2009-04-12T22:55:00.007+08:00

違背了零件沒壞不換的原則，花了1500大洋替單車(Giant IGUANA) 換了個奢侈品。維格 XPEDO MX-13 踏板。
花這麼多錢就只是換個踏板，心理實在是有很大罪惡感。

不過，花錢還是值得的啦！踩踏面積更大、抽車更穩、重量更輕(390g)，加上了用的是培林(Bearings: 3 Caridge)軸承，比原廠的滾珠式踏板更順暢、更有效率了。　

跑了一趟中寮山，新踏板再加上把前叉鎖死，比以前更輕鬆的就騎到了台視的發射站。

2009-04-03T09:54:00.000+08:00

依照學習寫程式的傳統, 第一個程式就是 Hello World !
這是我的第一篇 Blog 文章,
Hello World !

*	An optional starting asterisk indicates that the data is to be retrieved from the str string but ignored, i.e. it is not stored in the corresponding argument.
width	Specifies the maximum number of characters to be read in the current reading operation
modifiers	Specifies a size different from `int` (in the case of `d`, `i` and `n`), `unsigned int` (in the case of `o`, `u` and `x`) or `float` (in the case of `e`, `f` and `g`) for the data pointed by the corresponding additional argument: h : `short int` (for `d`, `i` and `n`), or `unsigned short int` (for `o`, `u` and `x`) l : `long int` (for `d`, `i` and `n`), or `unsigned long int` (for `o`, `u` and `x`), or `double` (for `e`, `f` and `g`) L : `long double` (for `e`, `f` and `g`)
type	A character specifying the type of data to be read and how it is expected to be read. See next table.