标签：Linux

linux下tomcat5.0.12不能在eclipse3.1中用sysdeo的插件启�动

Redhat linux9.0下tomcat5.0.12不能在eclipse3.1中用sysdeo的tomcatPluginV31插件启动。

我现在是上述的环境，也许不限于linux, eclipse3.1和tomcat5.0.12和tomcatPluginV31，记在这里意思是说，当你在tomcat不能在eclipse中用上sysdeo的插件启动时，不妨换一个tomcat的版本。

同样是上述环境，把tomcat5.0.12换成tomcat5.0.28后就可以正常启动了。

这两天找出这个原因费了点时间，jdk, eclipse, tomcatPlugin的版本都换过了，就是没有先换tomcat的版本：），以为都是5.0.*的版本，应该没有多大区别吧。可是，问题就恰恰出在这里了。

解决Redhat linux9.0下jdk1.4.2_01-b06的中文问题

这几天准备对学习日记作点小的改动（房子虽然太简单，也需要修整修整呀），把停了一个来月的学习日记开发环境在linux下搭起来了。当我运行java软件ArgoUML建模，发现不能在软件中输入汉字，保存对话框的“是”与“否”的中文字体为方框。我知道碰到了传说中的linux下java的中文乱码问题。

于是，请出google老师，他帮我找到了一篇帖子，于是，受文中的启发，在下面目录对文件font.properties.zh_CN.Redhat8.0作了一个符号链接font.properties.zh.Redhat，中文乱码问题就没有了。如下：


ln -s /usr/jdk1.4/jre/lib/font.properties.zh_CN.Redhat8.0 /usr/jdk1.4/jre/lib/font.properties.zh.Redhat

很简单吧，但是我不知道具体原因是什么。也许font.properties.zh.Redhat是Redhat系统在java中的默认字体设置文件？哪为什么在这个目录下又有这么多的字体设置文件，如下：


[root@localhost lib]# dir font.*

font.properties                 font.properties.ja.Sun           font.properties.zh_CN.Sun

font.properties.ja              font.properties.ja.Turbo         font.properties.zh_CN_UTF8.Sun

font.properties.ja_JP_UTF8.Sun  font.properties.ja.Turbo6.0      font.properties.zh.Redhat

font.properties.ja.Redhat6.1    font.properties.ko.Redhat8.0     font.properties.zh.Turbo

font.properties.ja.Redhat6.2    font.properties.Redhat6.1        font.properties.zh_TW.Redhat8.0

font.properties.ja.Redhat7.2    font.properties.Redhat8.0        font.properties.zh_TW.Sun

font.properties.ja.Redhat7.3    font.properties.SuSE8.0          font.properties.zh_TW_UTF8.Sun

font.properties.ja.Redhat8.0    font.properties.zh_CN.Redhat8.0

[root@localhost lib]#

***********************************************************************************

附上那篇介绍有Redhat linux9.0下java中文设置的文章，实际上是一篇讲Redhat linux9.0下oracle安装的文章，也许以后用得着，收藏在这里参考：

转自：http://www.xxlinux.com/linux/article/development/database/20060905/3956.html

RedHat9.0操作的oracle9i安装

[ 作者:Linux联盟收集  加入时间:2006-09-05 21:52:36  来自:Linux联盟收集 ]

作者：pxe2

先安装修改java

标准 jre/jdk 中只带了 redhat 6 的 font.properties, 需要建一个 font.properties.zh.Redhat 放在 redhat 的 jre/lib 目录下。打开 /usr/lib/X11/fonts/ttf-zh 或者 /usr/share/fonts/zh_CN/TrueType 下面的 font.dir， 将其中的一个中文字体名复制下来，比如 -misc-ZYSong18030-medium-r-normal--0-0-0-0-c-0-iso10646-1，按照 java 的字体规则改为 -misc-ZYSong18030-medium-r-normal--*-%d-*-*-c-*-iso10646-1，将 font.properties.zh 中的内容复制到 font.properties.zh.Redhat 中。

我选用字体 -misc-ZYSong18030-medium-r-normal--0-0-0-0-c-0-iso10646-1 是因为在 redhat 7.3 和 redhat 8.0 上都能用。

因为 jre/jdk 找不到 Redhat 的 true type 字体，在文件 font.properties.zh.Redhat 最后加入

appendedfontpath=/usr/lib/X11/fonts/ttf-zh

appendedfontpath=/usr/share/fonts/zh_CN/TrueType

将字体名全部替换成 -misc-ZYSong18030-medium-r-normal--*-%d-*-*-c-*-iso10646-1，替换后的 font.properties.zh.Redhat 如下：

# @(#)font.properties.zh.Redhat.linux 1.4 02/06/10

#

# Copyright 2002 Sun Microsystems, Inc. All rights reserved.

#

# Component Font Mappings

#

serif.0=-misc-ZYSong18030-medium-r-normal--*-%d-*-*-c-*-iso10646-1

serif.italic.0=-misc-ZYSong18030-medium-r-normal--*-%d-*-*-c-*-iso10646-1

serif.bold.0=-misc-ZYSong18030-medium-r-normal--*-%d-*-*-c-*-iso10646-1

serif.bolditalic.0=-misc-ZYSong18030-medium-r-normal--*-%d-*-*-c-*-iso10646-1

sansserif.0=-misc-ZYSong18030-medium-r-normal--*-%d-*-*-c-*-iso10646-1

sansserif.italic.0=-misc-ZYSong18030-medium-r-normal--*-%d-*-*-c-*-iso10646-1

sansserif.bold.0=-misc-ZYSong18030-medium-r-normal--*-%d-*-*-c-*-iso10646-1

sansserif.bolditalic.0=-misc-ZYSong18030-medium-r-normal--*-%d-*-*-c-*-iso10646-1

monospaced.0=-misc-ZYSong18030-medium-r-normal--*-%d-*-*-c-*-iso10646-1

monospaced.italic.0=-misc-ZYSong18030-medium-r-normal--*-%d-*-*-c-*-iso10646-1

monospaced.bold.0=-misc-ZYSong18030-medium-r-normal--*-%d-*-*-c-*-iso10646-1

monospaced.bolditalic.0=-misc-ZYSong18030-medium-r-normal--*-%d-*-*-c-*-iso10646-1

dialog.0=-misc-ZYSong18030-medium-r-normal--*-%d-*-*-c-*-iso10646-1

dialog.italic.0=-misc-ZYSong18030-medium-r-normal--*-%d-*-*-c-*-iso10646-1

dialog.bold.0=-misc-ZYSong18030-medium-r-normal--*-%d-*-*-c-*-iso10646-1

dialog.bolditalic.0=-misc-ZYSong18030-medium-r-normal--*-%d-*-*-c-*-iso10646-1

dialoginput.0=-misc-ZYSong18030-medium-r-normal--*-%d-*-*-c-*-iso10646-1

dialoginput.italic.0=-misc-ZYSong18030-medium-r-normal--*-%d-*-*-c-*-iso10646-1

dialoginput.bold.0=-misc-ZYSong18030-medium-r-normal--*-%d-*-*-c-*-iso10646-1

dialoginput.bolditalic.0=-misc-ZYSong18030-medium-r-normal--*-%d-*-*-c-*-iso10646-1

# Missing Glyph Character

#

default.char=274f

# Component Font Character Encodings

#

fontcharset.serif.0=sun.io.CharToByteISO8859_1

fontcharset.serif.1=sun.awt.motif.CharToByteX11GBK

fontcharset.sansserif.0=sun.io.CharToByteISO8859_1

fontcharset.sansserif.1=sun.awt.motif.CharToByteX11GBK

fontcharset.monospaced.0=sun.io.CharToByteISO8859_1

fontcharset.monospaced.1=sun.awt.motif.CharToByteX11GBK

fontcharset.dialog.0=sun.io.CharToByteISO8859_1

fontcharset.dialog.1=sun.awt.motif.CharToByteX11GBK

fontcharset.dialoginput.0=sun.io.CharToByteISO8859_1

fontcharset.dialoginput.1=sun.awt.motif.CharToByteX11GBK

# Exclusion Ranges

#

# XFontSet Information

#

fontset.serif.plain=

-misc-ZYSong18030-medium-r-normal--*-%d-*-*-c-*-iso10646-1

fontset.serif.italic=

-misc-ZYSong18030-medium-r-normal--*-%d-*-*-c-*-iso10646-1

fontset.serif.bold=

-misc-ZYSong18030-medium-r-normal--*-%d-*-*-c-*-iso10646-1

fontset.serif.bolditalic=

-misc-ZYSong18030-medium-r-normal--*-%d-*-*-c-*-iso10646-1

fontset.sansserif.plain=

-misc-ZYSong18030-medium-r-normal--*-%d-*-*-c-*-iso10646-1

fontset.sansserif.italic=

-misc-ZYSong18030-medium-r-normal--*-%d-*-*-c-*-iso10646-1

fontset.sansserif.bold=

-misc-ZYSong18030-medium-r-normal--*-%d-*-*-c-*-iso10646-1

fontset.sansserif.bolditalic=

-misc-ZYSong18030-medium-r-normal--*-%d-*-*-c-*-iso10646-1

fontset.monospaced.plain=

-misc-ZYSong18030-medium-r-normal--*-%d-*-*-c-*-iso10646-1

fontset.monospaced.italic=

-misc-ZYSong18030-medium-r-normal--*-%d-*-*-c-*-iso10646-1

fontset.monospaced.bold=

-misc-ZYSong18030-medium-r-normal--*-%d-*-*-c-*-iso10646-1

fontset.monospaced.bolditalic=

-misc-ZYSong18030-medium-r-normal--*-%d-*-*-c-*-iso10646-1

fontset.dialog.italic=

-misc-ZYSong18030-medium-r-normal--*-%d-*-*-c-*-iso10646-1

fontset.dialog.bold=

-misc-ZYSong18030-medium-r-normal--*-%d-*-*-c-*-iso10646-1

fontset.dialog.bolditalic=

-misc-ZYSong18030-medium-r-normal--*-%d-*-*-c-*-iso10646-1

fontset.dialog.plain=

-misc-ZYSong18030-medium-r-normal--*-%d-*-*-c-*-iso10646-1

fontset.dialoginput.italic=

-misc-ZYSong18030-medium-r-normal--*-%d-*-*-c-*-iso10646-1

fontset.dialoginput.bold=

-misc-ZYSong18030-medium-r-normal--*-%d-*-*-c-*-iso10646-1

fontset.dialoginput.bolditalic=

-misc-ZYSong18030-medium-r-normal--*-%d-*-*-c-*-iso10646-1

fontset.dialoginput.plain=

-misc-ZYSong18030-medium-r-normal--*-%d-*-*-c-*-iso10646-1

#fontset.default=

#-b&h-lucida-medium-r-normal-sans-*-%d-*-*-p-*-iso10646-1,

#-tlc-song-medium-r-normal--*-%d-*-*-c-*-gbk-0

fontset.default=

-misc-ZYSong18030-medium-r-normal--*-%d-*-*-c-*-iso10646-1

appendedfontpath=/usr/lib/X11/fonts/ttf-zh

appendedfontpath=/usr/share/fonts/zh_CN/TrueType

使用 Installanywhere 我们编译安装程序选择 "其它 java 平台" 编译成一个 java 的 setup.jar 文件，

在 Redhat 上面写一个批处理/脚本文件, set classpath , 包含 setup.jar，

批处理/脚本文件中使用 java install 启动安装程序。

繁体中文依法炮制即可，建立 font.properties.zh_TW.Redhat 文件，将其中的字体名改为一个繁体中文字体名，

在文件末尾加上合适的 appendedfontpath

___________________________________________________________

1安装好RedHat9.0操作系统，确保安装了以下的RPM开发包

gcc

cpp

glibc-devel

compat-libstdc++

glibc-kernheaders

binutils

可以使用命令来查看是否已安装了这些包

rpm -q gcc cpp compat-libstdc++ glibc-devel glibc-kernheaders binutils

2从Oracle官方网站下载Oracle9i安装文件并使用如下命令解包

zcat lnx_920_disk1.cpio.gz | cpio -idmv

zcat lnx_920_disk2.cpio.gz | cpio -idmv

zcat lnx_920_disk3.cpio.gz | cpio -idmv

(注意磁盘空间)

然后会有Disk1 Disk2 Disk3三个子目录。

3设置内核参数

echo 4294967295 > /proc/sys/kernel/shmmax，建议放到/etc/rc.local文件里。

或

编辑/etc/sysctl.conf

kernel.shmmax=4294967295

我有512MB内存，所以设置这个数值。可根据实际情况设置。

4创建Oracle用户帐号和安装目录

在shell下,作为root

groupadd dba

groupadd oinstall

useradd -g oinstall -G dba oracle

passwd oracle

mkdir /opt/oracle

mkdir /opt/oracle/product

mkdir /opt/oracle/product/9.2.0

chown -R oracle.oinstall /opt/oracle

mkdir /var/oracle

chown oracle.dba /var/opt/oracle

chmod 755 /var/opt/oracle

5设置环境变量

编辑/home/oracle/.bash_profile文件，添加下列行

export LD_ASSUME_KERNEL=2.4.1

export ORACLE_BASE=/opt/oracle

export ORACLE_HOME=/opt/oracle/product/9.2.0

export ORACLE_SID=ora9i

export ORACLE_TERM=xterm

$ORACLE_HOME/network/admin

export NLS_LANG=AMERICAN_AMERICAN.ZHS16GBK

export ORA_NLS33=$ORACLE_HOME/ocommon/nls/asmin/data

LD_LIBRARY_PATH=$ORACLE_HOME/lib:/lib:/usr/lib

LD_LIBRARY_PATH=$LD_LIBRARY_PATH:/usr/local/lib

export LD_LIBRARY_PATH

export PATH=$PATH:$ORACLE_HOME/bin

CLASSPATH=$ORACLE_HOME/JRE:$ORACLE_HOME/jlib:$ORACLE_HOME/rdbms/jlib

CLASSPATH=$CLASSPATH:$ORACLE_HOME/network/jlib

export CLASSPATH

6安装

进入Disk1目录

./runInstaller

当link进行到61%时出现一个关于ins_oemagent错误，选择ignore，安装完后修复

当link进行到84%时出现一个关于ins_ctx错误，编辑$ORACLE_HOME/ctx/lib/env_ctx.mk文件，把$(LDLIBFLAG)dl加到以下位置

INSO_LINK=-L$(CTXLIB)$ (LDLIBFLAG)m $(LDLIBFLAG)dl处。

安装完成

修复第一个错误

在shell下，oracle用户

cd $ORACLE_HOME/network/lib

make -f ins_client.mk install

编辑$ORACLE_HOME/ctx/lib/ins_ctx文件

13-14行处

$(LINK) $(CTXHXOBJ) $(INSO_LINK)

为

$(LINK) -ldl $(CTXHXOBJ) $(INSO_LINK)

7启动数据库、监听程序、web server。

启动数据库

Sqlplus " / as sysdba"

SQL>startup

启动监听程序

lsnrctl

启动web server

cd $ORACLE_HOME/Apache/Apache/bin

./startJServ.sh'

来源：linuxfans

还有问题请来论坛寻求帮助：http://www.xxlinux.com/bbs/

9.2. Manipulating Strings

9.2. Manipulating Strings

1、String Length

expr "$string" : '.*'

3、Index这个表达式跟java的用法好像不同

expr index $string $substring

    Numerical position in $string of first character in $substring that matches.


   5 echo `expr index "$stringZ" 1c`              # 3

   6 # 'c' (in #3 position) matches before '1'.

4?{string:position:length}负数参数的用法有点怪

    Extracts $length characters of substring from $string at $position.


  16 echo ${stringZ:-4}                           # abcABC123ABCabc

  17 # Defaults to full string, as in ${parameter:-default}.

  18 # However . . .

  19

  20 echo ${stringZ:(-4)}                         # Cabc

  21 echo ${stringZ: -4}                          # Cabc

  22 # Now, it works.

  23 # Parentheses or added space "escape" the position parameter.

  24

  25 # Thank you, Dan Jacobson, for pointing this out.

而且下面这段不懂：


    If the $string parameter is "*" or "@", then this extracts a maximum of

$length positional parameters, starting at $position.

       1 echo ${*:2}          # Echoes second and following positional

parameters.

       2 echo ${@:2}          # Same as above.

       3

       4 echo ${*:2:3}        # Echoes three positional parameters, starting

at second.

5、Example 9-12. Emulating getopt其中的字符串处理不甚明了


  14       if [ ${1:0:1} = '/' ]

  15       then

  16           tmp=${1:1}               # Strip off leading '/' . . .

  17           parameter=${tmp%%=*}     # Extract name.

  18           value=${tmp##*=}         # Extract value.

  19           echo "Parameter: '$parameter', value: '$value'"

  20           eval $parameter=$value

  21       fi

6、awk处理函数不懂


  14 # The awk equivalent of ${string:pos:length} is

substr(string,pos,length).

  15 echo | awk '

  16 { print substr("'"${String}"'",3,4)      # skid

  17 }

  18 '

7、9.2.2. Further Discussion进一步讨论的几个例子没看

英语疑问：

1、emulation, getopt

A simple emulation of getopt  using substring extraction constructs.

9.1. Internal Variables

9.1. Internal Variables

1、不懂：


$DIRSTACK

    the top value in the directory stack (affected by pushd and popd)

    This builtin variable corresponds to the dirs command, however dirs shows

    the entire contents of the directory stack.

2、

 


$EUID

    "effective" user ID number

    Identification number of whatever identity the current user has assumed,

    perhaps by means of su.

    Caution The $EUID is not necessarily the same as the $UID.

3、


  $GLOBIGNORE

    A list of filename patterns to be excluded from matching in globbing.

4、


     root# echo ${GROUPS[1]}

     1

5、


    $IFS defaults to whitespace (space, tab, and newline), but may be changed,

    for example, to parse a comma-separated data file. Note that $* uses the

    first character held in $IFS. See Example 5-1.

     bash$ echo $IFS | cat -vte

     $

     bash$ bash -c 'set w x y z; IFS=":-;"; echo "$*"'

     w:x:y:z

6、IFS是空格时，字符间的多个空格视为一个分隔符，第一个字符前面的空格会忽略不计。见例子ifs.sh。


              14 IFS=" "

              15 var=" a  b c   "

 ...

              26 IFS=:

              27 var=":a::b:c:::"               # Same as above, but substitute

运行结果：


[mdx@localhost abs-exercises]$ ./ex9-1.sh

IFS=" "

-------

the arg is: [a]

the arg is: [b]

the arg is: [c]

IFS=:

-----

the arg is: []

the arg is: [a]

the arg is: []

the arg is: [b]

the arg is: [c]

the arg is: []

the arg is: []

[mdx@localhost abs-exercises]$

7、$LINENO 不懂


$LINENO

    This variable is the line number of the shell script in which this

variable

    appears. It has significance only within the script in which it appears,

    and is chiefly useful for debugging purposes.

       1 # *** BEGIN DEBUG BLOCK ***

       2 last_cmd_arg=$_  # Save it.

       3

       4 echo "At line number $LINENO, variable \"v1\" = $v1"

       5 echo "Last command argument processed = $last_cmd_arg"

       6 # *** END DEBUG BLOCK ***

8、$PIPESTATUS不懂，并且在本机上的执行结果与书中的不同


     bash$ echo $PIPESTATUS

     0

     bash$ ls -al | bogus_command

     bash: bogus_command: command not found

     bash$ echo $PIPESTATUS

     141

     bash$ ls -al | bogus_command

     bash: bogus_command: command not found

     bash$ echo $?

     127

...

          bash$ echo ${PIPESTATUS[@]}

9、不懂

$PWD的：


      22 # rm -f .[^.]* ..?*   to remove filenames beginning with multiple

dots.      23 # (shopt -s dotglob; rm -f *)   will also work.

      24 # Thanks, S.C. for pointing this out.

10、不懂$SHELLOPTS的用法


[mdx@localhost abs-exercises]$ echo $SHELLOPTS

braceexpand:emacs:hashall:histexpand:history:interactive-comments:monitor

11、$SHLVL的用法


$SHLVL

    Shell level, how deeply Bash is nested. If, at the command line, $SHLVL is

    1, then in a script it will increment to 2.

12、$TMOUT的用法不懂，例子example9-2~9-4不懂

13、$UID，下面这段话的意思不懂

This is the current user's real id, even if she has temporarily assumed

    another identity through su.

14、example9-7太复杂了，留在这里备忘


    Caution The $* and $@ parameters sometimes display inconsistent and

            puzzling behavior, depending on the setting of $IFS.

    ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━

    Example 9-7. Inconsistent $* and $@ behavior

15、set命令的用法


[mdx@localhost abs-exercises]$ set a b c

[mdx@localhost abs-exercises]$ echo $1 $2 $3

a b c

[mdx@localhost abs-exercises]$

16、$!的用法

书上的例子：

LOG=$0.log

COMMAND1="sleep 100"

echo "Logging PIDs background commands for script: $0" >> "$LOG"

# So they can be monitored, and killed as necessary.

echo >> "$LOG"

# Logging commands.

echo -n "PID of \"$COMMAND1\":  " >> "$LOG"

${COMMAND1} &

echo $! >> "$LOG"

# PID of "sleep 100":  1506

# Thank you, Jacques Lederer, for suggesting this.

#下面这句不大懂：eval, kill -9

#possibly_hanging_job & { sleep ${TIMEOUT}; eval 'kill -9 $!' &> /dev/null; }      

# Forces completion of an ill-behaved program.

# Useful, for example, in init scripts.

# Thank you, Sylvain Fourmanoit, for this creative use of the "!" varia

英语疑问:

1、subtleties, nuances

This requires learning their subtleties and nuances.

2、necessarily

$SHELL does not necessarily give the correct answer.

3、collation order, mishandled

$LC_COLLATE

    Often set in the .bashrc or /etc/profile files, this variable controls

    collation order in filename expansion and pattern matching. If mishandled,

    LC_COLLATE can cause unexpected results in filename globbing.

4、revert, customary

To revert to the customary behavior of bracket matching, set LC_COLLATE to C by an export LC_COLLATE=C in /etc/profile and/or ~/.bashrc.

5、expedient

In a script, it may be expedient to temporarily add a directory to the path

    in this way.

6、likewise

         $SHELL, the name of the user's login shell, may be set from /

         etc/passwd or in an "init" script, and it is likewise not a

         Bash builtin.

8.2. Numerical Constants

8.2. Numerical Constants

1、Example 8-4. Representation of numerical constants

同C语言一样，字符也是整数。但是@和_代表是多少不知道？而且把它们转化为十进制的方法忘记了。

  32 let "b64 = 64#@_"

  33 echo "base-64 number = $b64"             # 4031

  34 # This notation only works for a limited range (2 - 64) of ASCII characters  35 # 10 digits + 26 lowercase characters + 26 uppercase characters + @ + _

  36

  37

  38 echo

  39

  40 echo $((36#zz)) $((2#10101010)) $((16#AF16)) $((53#1aA))

  41                                          # 1295 170 44822 3375

英语疑难: evaluates

A number with an embedded # evaluates as BASE#NUMBER (with range and notational restrictions).

8.1. Operators

Chapter 8. Operations and Related Topics

8.1. Operators

1、Example 8-1. Greatest common divisor最大公约数的算法不懂，里面的练习：判断命令行参数是否是整数不懂，记在这里。

2、发现一个问题，bash的算术操作符只能进行整数的运算，要进行其它的复杂点的运算：如开方、小数等怎么办呢？

3、Example 8-2. Using Arithmetic Operations

这个例子有不少地方不明白，记在这里以后进一步解决：

我知道 let "z = 2 + 3" 相当于 (( z = 2 + 3 ))，根据：


Similar to the let command, the ((...)) construct permits arithmetic expansion

and evaluation.

1）、


      10 : $((n = $n + 1))

      11 #  ":" necessary because otherwise Bash attempts

      12 #+ to interpret "$((n = $n + 1))" as a command.

2)、      20 n=$(($n + 1))

3)、

      23 : $[ n = $n + 1 ]

      24 #  ":" necessary because otherwise Bash attempts

      25 #+ to interpret "$[ n = $n + 1 ]" as a command.

      26 #  Works even if "n" was initialized as a string.

4)、

      29 n=$[ $n + 1 ]

      30 #  Works even if "n" was initialized as a string.

      31 #* Avoid this type of construct, since it is obsolete and

nonportable.

      32 #  Thanks, Stephane Chazelas.

5)、      44 : $(( n++ ))       # : $(( ++n )) also works.

6）、      47 : $[ n++ ]         # : $[ ++n ]] also works

4、bash不能处理浮点数：


Bash does not understand floating point arithmetic. It treats numbers containing a decimal point as strings.

5、

if [ $condition1 -a $condition2 ] 相当于 if [[ $condition1 && $condition2 ]]

，但是&&不能用在[...]结构中，这些有什么规律吗？真不好掌握啊。

6、Example 8-3. Compound Condition Tests Using && and ||


6 if [ "$a" -eq 24 ] && [ "$b" -eq 47 ]

17 #  Note:  if [[ $a -eq 24 && $b -eq 24 ]]  works.

20 #    (The "&&" has a different meaning in line 17 than in line 6.)

我不懂&&在6行和17行有什么区别？

7、不懂 $((...))的用法


     bash$ echo $(( 1 && 2 )) $((3 && 0)) $((4 || 0)) $((0 || 0))

     1 0 1 0

英语疑问:

1、Modulo turns up surprisingly often in various numerical recipes.

2、erroneous

An operation that takes a variable outside these limits will give an erroneous result.

3、flip, relevant, fly

"Bit flipping" is more relevant to compiled languages, such

as C and C++, which run fast enough to permit its use on the fly.

4、miscellaneous operators

5、evaluated

All the operations are evaluated (with possible side effects), but only the last operation is returned.

7.4. Nested if/then Condition Tests 7.5. Testing Your Knowledge of Tests

7.4. Nested if/then Condition Tests

嵌套条件测试相当于复合条件测试中的 &&

7.5. Testing Your Knowledge of Tests


  10      if [ -f /usr/bin/netscape -a -f /usr/share/doc/HTML/index.html ]; then  11              netscape /usr/share/doc/HTML/index.html &

  12      fi

有2个问题:

1、在测试条件中多个测试条件(如上：-f -a -f)的组合规则和形式是怎么样的？

2、"netscape /usr/share/doc/HTML/index.html &"后面加一个&是什么意思？

另外，这章布置了习题，分析/etc/X11/xinit/xinitrc文件中的条件语句，这遍就略过习题了。下同。

英语疑问：

1、excerpt

This file contains quite a number of if/then tests, as the following excerpt shows.

2、failsafe, fallbacks

 # failsafe settings.  Although we should never get here

 # (we provide fallbacks in Xclients as well) it can't hurt.

linux文本模式下w3m/0.5.1,zhcon0.2.6看big5网页

今天，在linux文本模式下（w3m/0.5.1,zhcon0.2.6）看一位朋友推荐的http://linux.vbird.org时，发现是big5网页，默认的配置不能正常查看。经试验，作下列改动解决：

在zhcon.conf里把：


#auto,auto-gb,auto-big5,manual

autoencode = manual

改为：


#auto,auto-gb,auto-big5,manual

autoencode = auto

在w3m/0.5.1中按"o"调出设置页面：

把


Charset Settings

Display charset                                  [Chinese Taiwan (Big5, CP950)]

Default document charset                         [Chinese (EUC-CN, GB2312)    ]

中的Display charset由：Chinese (EUC-CN, GB2312)改为：Chinese Taiwan (Big5, CP950)

但是，这样每次都要手工修改w3m中的设置，还没有找到自动的切换设置。有谁知道了告诉一下。

7.3. Other Comparison Operators

1、太复杂了，记不住的，有没有什么规则呀？

The == comparison operator behaves differently within a double-brackets         test than within single brackets.


            1 [[ $a == z* ]]    # True if $a starts with an "z" (pattern matchin            2 [[ $a == "z*" ]]  # True if $a is equal to z* (literal matching).

            3

            4 [ $a == z* ]      # File globbing and word splitting take place.

            5 [ "$a" == "z*" ]  # True if $a is equal to z* (literal matching).

            6

            7 # Thanks, St?phane Chazelas

2、测试数值用[ "$a" -ne "$b" ]，测试字符串用[ "$a" != "$b" ]。

3、Example 7-6. Testing whether a string is null通过几个例子反复说：测试字符串一定要用双引号把字符串变量括起来!从前面看，测试数值变量同样是把变量用双引号括起来的，这样，可以总结说，无论是数值变量和字符串变量都必须加双引号。

4、Example 7-7. zmore中测试文件类型的语句，不懂


if [ ${filename##*.} != "gz" ]

# Using bracket in variable substitution.

then

  echo "File $1 is not a gzipped file!"

  exit $NOTGZIP

fi

5、复合比较：

1）、[[ condition1 && condition2 ]]相当于 [ "$exp1" -a "$exp2" ]

2）、在比较空字符串时，应该在有可能是空字符串的字符串前加上额外的字符，文中说：


As S.C. points out, in a compound test, even quoting the string variable

     might not suffice. [ -n "$string" -o "$a" = "$b" ] may cause an error with

     some versions of Bash if $string is empty. The safe way is to append an

     extra character to possibly empty variables, [ "x$string" != x -o "x$a" =

     "x$b" ] (the "x's" cancel out).

英语疑问：

1、globbing

File globbing and word splitting take place.

2、Caution advised, however.

  10 #  Bash permits integer operations and comparisons on variables

  11 #+ whose value consists of all-integer characters.

  12 #  Caution advised, however.

3、sealing wax, cabbages and kings

   2 #  str-test.sh: Testing null strings and unquoted strings,

   3 #+ but not strings and sealing wax, not to mention cabbages and kings . . .

4、compound comparison

5、suffice:

As S.C. points out, in a compound test, even quoting the string variable

     might not suffice.

6、the "x's" cancel out（上面5的2））