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UNIX Shells by Example(Fourth Edition)��M��W�记-2.Shells�~�程快速入�?�? 之Korn Shell

Mon, 30 Jun 2008 02:25:00 GMT

摘要: 阅读全文

一叶笑�?/a> 2008-06-30 10:25 发表评论

UNIX Shells by Example(Fourth Edition)��M��W�记-2.Shells�~�程快速入�?�? 之Bourne Shell

Wed, 25 Jun 2008 10:29:00 GMT

摘要: Bourne shell语法和结构： Shbang�? "shbang" 是脚本�v始行�Q�告诉kernel那个shell解析. #!位于行头�?!/bin/sh ... 阅读全文

一叶笑�?/a> 2008-06-25 18:29 发表评论

UNIX Shells by Example(Fourth Edition)��M��W�记-2.Shells�~�程快速入�?一)之C Shell和TC Shell

Thu, 19 Jun 2008 05:52:00 GMT

2.1 快速浏览Shell脚本�Q?br /> C shell �?TC shell �c�M��于C语言语法
Bourne shell 是基于Algol语言
Bash和Korn shells 混合了Bourne和C shells, 但是��h��于Bourne shell.
2.3 C 和TC Shell 语法�l�构

shbang�?	"shbang" 行告诉采用哪个shell来解析脚�? 首先�?tt>#, `!`, shell的�\�?例如�Q?!/bin/csh or #!/bin/tcsh
注释	�?tt>#�W�号。例如： # This is a comment
通配�W?/p>	``, `?`, and `[ ]` 用于文�g名的扩展. `!` 是历史字�W?br /> `<` , `>` , `>>` , `<&`, and `\|` 用于标准IO的重定向和管�?br /> ��Z��避免�q�些�W�号被shell解析器解释，shell中必��M��用\或�?。例如： rm ; ls ??; cat file[1-3]; !! echo "How are you?" echo Oh boy\!
输出昄��	`echo` 输出昄�� echo "Hello to you\!"
局部变�?/p>	局部变量存在于当前shell中。��用set讄��。例�?br /> set variable_name = value set name = "Tom Jones"
全局变量	全局变量被称为环境变量。例�?br /> setenv VARIABLE_NAME value setenv PRINTER Shakespeare
从变量中提取�?/p>	��Z��从变量中提取之，使用$在变量前。例如： echo $variable_name echo $name echo $PRINTER
��d��用户输入	使用 `$<` ��d��一行到一个变量中�Q�例如： echo "What is your name?" set name = $<
参数	可以从命令行中传入参数。两�U�方式接受这些参数��\|��一个是位置参数�Q�另外一个是argv数组。例如： % scriptname arg1 arg2 arg3 ... 使用位置参数:
	`echo $1 $2 $3`		`arg1` 指定�?/span>`$1`, `arg2` to `$2`, etc.
	`echo $*`		所有的参数
	使用argv数组:
	`echo $argv[1] $argv[2] $argv[3]`
	`echo $argv[*]`		所有参�?/span>
	`echo $#argv`		参数�?/span>
数组	数组是一列被�I�格分隔的字�W�。��?)把字�W�都包含�q�去�?br /> 用内建的`shift`命名可以�U�d��左边的字从list中�?br /> 不同于C, index起始值是1而不�?. 例如�Q?/p>
	`set word_list = ( word1 word2 word3 )`
	set names = ( Tom Dick Harry Fred ) shift names		从list中删�?/span>`Tom`
	echo $word_list[1] echo $word_list[2] echo $word_list or $word_list[] echo $names[1] echo $names[2] echo $names[3] echo $names or echo $names[]		昄��W�一�?br /> 昄��W�二�?br /> 昄��所�?/span>
命��o替换	使用` `例如�Q?/span>
	set variable_name=`command` echo $variable_name
	set now = `date` echo $now echo "Today is `date`"
��术	使用@来表�C��结果的保存变量。例�?br /> @ n = 5 + 5 echo $n
操作�W?/p>
	相等�?
	`==`
	`!=`
	Relational:
	`>`	greater than
	`>=`	greater than or equal to
	`<`	less than
	`<=`	less than or equal to
	逻辑�?
	`&&`	and
	`\|\|`	or
	`!`	nSot
条�g语句	`if` `then.` `if` 必须�?tt>endif�l�尾. �q�可以��?tt>if/else。例如：
	The `if` construct is: if ( expression ) then block of statements endif The `if/else` construct is: if ( expression ) then block of statements else block of statements endif			The `if/else/else if` construct is: if ( expression ) then block of statements else if ( expression ) then block of statements else if ( expression ) then block of statements else block of statements endif switch ( "$color" ) case blue: echo $color is blue breaksw case green: echo $color is green breaksw case red: case orange: echo $color is red or orange breaksw default: echo "Not a valid color" endsw
	switch �l�构: switch variable_name case constant1: statements case constant2: statements case constant3: statements default: statements endsw
循环	两种�c�d��循环语句�Q?tt>while�?tt>foreach 循环控制中可以��?tt>break�?tt>continue.例如�Q?br /> while ( expression ) block of statements end foreach variable ( word list ) block of statements end ------------------------------ foreach color (red green blue) echo $color end
文�g��试	例如�Q?/span>
	`–r`	当前用户能读文�g
	`–w`	当前用户能写文�g
	`–x`	当前用户能执行文�?/span>
	`–e`	文�g存在
	`–o`	当前用户拥有文�g
	`–z`	文�g长度�?
	`–d`	文�g是目�?/span>
	`–f`	文�g是普通文�?/span>

2.3.1 C/TC Shell 脚本

Example 2.2.

1   #!/bin/csh –f
2   # The Party Program––Invitations to friends from the "guest" file
3   set guestfile = ~/shell/guests
4   if ( ! –e "$guestfile" ) then
echo "$guestfile:t non–existent"
exit 1
5   endif
6   setenv PLACE "Sarotini's"
7   @ Time = `date +%H` + 1
8   set food = ( cheese crackers shrimp drinks "hot dogs" sandwiches )
9   foreach person ( `cat $guestfile` )
10      if ( $person =~ root ) continue
11      mail –v –s "Party" $person << FINIS   # Start of here document 

         Hi $person!Please join me at $PLACE for a party!

         Meet me at $Time o'clock. I'll bring the ice cream.

        Would you please bring $food[1] and anything else you would like to eat?

        Let me know if you can make it. Hope to see you soon.
Your pal,
ellie@`hostname`       # or `uname -n`
12       FINIS
13       shift food
14       if ( $#food ==  0 ) then
set food = ( cheese crackers shrimp drinks "hot dogs" sandwiches )
endif
15   end
echo "Bye..."

解释�Q?/pre>
1.告诉kernel�Q�这是C shell脚本. ”–f“表示快速启�?���是说不要执�?tt>.cshrc.

2.注释�?br />
3.变量guestfile 被设�|��ؓ调用guests的全路径

4.行读入，如果guests不存在，打印 "guests nonexistent" �Q�退�����本�?br />
5.endif

6.PLACE 环境变量

7.Time局部变量�?tt>@是内建算术�?br />
8.food数组�?br />
9.foreach循环。命令替�?tt>`cat $guestfile`. 

10.条�g���试

11.foreach循环

12.FINIS是用户定义的�l�结�W?br />
13.shift命��o取得下一个person

14.如果food为空�Q�将会重�|��?br />
15.循环�l�束标志
 

一叶笑�?/a> 2008-06-19 13:52 发表评论

Wed, 18 Jun 2008 02:37:00 GMT

Shell是一些特定的�E�序接口�Q�用于用户和UNIX/Linux操作�pȝ��怺�互。如下图所�C�：
1.Unix Shell
(1) Bourne shell (sh)是标准的UNIX shell, 用于��理�pȝ��. 很多�pȝ��理的脚本。例�?tt>rc start�?/tt>stop脚本以及shutdown 是Bourne shell 脚本;�~�省的Bourne shell 表示�?$)
(2) C shell (csh)是伯克利开发的�Q�增加了很多新的特征, 例如command-line history, aliasing, built-in arithmetic, filename completion, and job control. Bourne shell 脚本快于和简单于C shell. �~�省C shell 表示�?%)
(3) Korn shell是Bourne shell的超�? Korn shell 增强的特征有editable history, aliases, functions, regular expression wildcards, built-in arithmetic, job control, coprocessing, and special debugging features. Bourne shell is 完全向上兼容Korn shell,q�~�省的Korn shell提示�W�是 ($)
2.Shell的职责是�Q?br /> (1)��d��输入和解析命令行
(2)计算�Ҏ(gu��)��字符�Q�例如wildcards和历史字�W?br /> (3)建立��道�Q�重定向和后台处�?br /> (4)处理信号
(5)建立可执行程�?br /> 3.Shell命��o执行图：

4.�pȝ��启动和登录Shell
启动�pȝ��->>调用init->>分配PID=1->>打开�l�端�U?>>建立stdin,stdout�?/tt>stderr->>输入login name,->>输入password->> /bin/login通过passwd文�g验证你的密码.如果login验证成功�Q�则会开始徏立初始环�?HOME, SHELL, USER, �?LOGNAME 是从passwd中抽取的变量�? HOME变量指定你的home目录, SHELL指定��d��shell的名�U?它是passwd文�g的最后一个入�? USER �?LOGNAME 变量指定你的��d��? ->>执行passwd文�g中的最后一个入口程�?font face="Courier New">. 通常�q�个�E�序��是shell. 如果passwd文�g中的最后一个程序是 /bin/csh, C shell被执行，如果�?/bin/bash 或者null, Bash shell执行. 如果�?/bin/ksh 或�?/bin/pdksh, Korn shell 被执�? ->>��查系�l�初始化文�g建立->>��查登录目录下的初始化文�g. ->>�{�待用户输入�?br /> 4.1解析命��o行的�q�程�Q?br /> (1)执行历史记录替换 (2)命名行被分割成符合或者字 (3)更新历史记录 (4)处理引用 (5)别名替换和定义函�?br /> (6)建立重定�?后台和管�?br /> (7)执行变量($user, $name, etc.) 替换 (8)执行命��o替换 (9)文�g名替换，调用globbing (cat abc.??, rm *.c, etc.) (10)执行命��o 4.2命��o的类�?br /> (1)别名 (2)关键�?br /> (3)函数 (4)内徏命��o (5)可执行命�?br /> 5.�q�程和Shell 5.1查看�q�程 $ ps aux (BSD/Linux ps) (use ps -ef for SVR4) $ pstree 6.环境和��?br /> 1 $ id uid=502(ellie) gid=502(ellie) 查看用户的标识user identification (UID), group identifications (GID), 6.3修改文�g许可 chmod Permission Modes Decimal Binary Permissions 0 000 none 1 001 --x 2 010 -w- 3 011 -wx 4 100 r-- 5 101 r-x 6 110 rw- 7 111 rwx chmod is as follows: r = read; w = write; x = execute; u = user; g = group; o = others; a = all. 1 $ chmod 755 file $ ls –l file –rwxr–xr–x 1 ellie 0 Mar 7 12:52 file 2 $ chmod g+w file $ ls -l file –rwxrwxr-x 1 ellie 0 Mar 7 12:54 file 3 $ chmod go-rx file $ ls -l file –rwx-w---- 1 ellie 0 Mar 7 12:56 file 4 $ chmod a=r file $ ls -l file –r--r--r-- 1 ellie 0 Mar 7 12:59 file chown改变文�g和目录的所有属�?br /> 1 $ ls -l filetest -rw-rw-r-- 1 ellie ellie 0 Jan 10 12:19 filetest 6.4工作目录 1 > cd / 2 > pwd / 3 > bash 4 $ cd /home 5 $ pwd /home 6 $ exit 7 > pwd / > 6.5查看变量 $ env 6.6重定向和��道重定�?br /> 1 $ who > file 2 $ cat file1 file2 >> file3 3 $ mail tom < file 4 $ find / -name file -print 2> errors 5 % ( find / -name file -print > /dev/tty) >& errors ��道 | who | wc 6.7Shell和信�?br /> 标准信号 Number Name Description Action 0 EXIT Shell exits Termination 1 SIGHUP Terminal has disconnected Termination 2 SIGINT User presses Ctrl-C Termination 3 SIGQUIT User presses Ctrl-\ Termination 4 SIGILL Illegal hardware instruction Program error 5 SIGTRAP Produced by debugger Program error 8 SIGFPE Arithmetic error; e.g., division by zero Program error 9 SIGKILL Cannot be caught or ignored Termination 一叶笑�?/a> 2008-06-18 10:37 发表评论

Decimal	Binary	Permissions
0	000	none
1	001	`--x`
2	010	`-w-`
3	011	`-wx`
4	100	`r--`
5	101	`r-x`
6	110	`rw-`
7	111	`rwx`

Number	Name	Description	Action
0	`EXIT`	Shell exits	Termination
1	`SIGHUP`	Terminal has disconnected	Termination
2	`SIGINT`	User presses Ctrl-C	Termination
3	`SIGQUIT`	User presses Ctrl-\	Termination
4	`SIGILL`	Illegal hardware instruction	Program error
5	`SIGTRAP`	Produced by debugger	Program error
8	`SIGFPE`	Arithmetic error; e.g., division by zero	Program error
9	`SIGKILL`	Cannot be caught or ignored	Termination

7777久久亚洲中文字幕,亚洲av午夜国产精品无码中文字 ,国产成人亚洲精品

UNIX Shells by Example(Fourth Edition)��M���W�记-2.Shells�~�程快速入�?�? 之Korn Shell

UNIX Shells by Example(Fourth Edition)��M���W�记-2.Shells�~�程快速入�?�? 之Bourne Shell

UNIX Shells by Example(Fourth Edition)��M���W�记-2.Shells�~�程快速入�?一)之C Shell和TC Shell

2.3.1 C/TC Shell 脚本

Example 2.2.

UNIX Shells by Example(Fourth Edition)��M��W�记-2.Shells�~�程快速入�?�? 之Korn Shell

UNIX Shells by Example(Fourth Edition)��M��W�记-2.Shells�~�程快速入�?�? 之Bourne Shell

UNIX Shells by Example(Fourth Edition)��M��W�记-2.Shells�~�程快速入�?一)之C Shell和TC Shell