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Gavin.lee — Sun, 29 Nov 2009 04:10:00 GMT

shift命��o
向脚本传递参数时�Q�有旉��要将每一个参数偏�U�M��处理选项�Q�这��是 shift命��o的功能。它每次��参��C��|�向左偏�U�M��位，下面用一�D늮�单脚本详�q�其功能。脚本��?while循环反馈所有传递到脚本的参数。��用shift命��o来处理传递到脚本的每一个参敎ͼ�

Shell代码

#!/bin/sh
loop=0
while [ $# -ne 0 ]
do
echo $1
shift
done

#!/bin/sh
loop=0
while [ $# -ne 0 ]
do
echo $1
shift
done

使用shift处理文�g大小写�{�?

Shell代码

!#/bin/sh
# tr_case
# convert files to either upper or lower case
FILES=""
TRCASE=""
EXT=""
OPT=no
# gets called when a conversion fails
error_msg()
{
_FILENAME=$1
echo "`basename $0`: Error the conversion failed on $_FILENAME"
}
if [ $# -eq 0 ]
then
echo "For more info try `basename $0` --help"
exit 1
fi
while [ $# -gt 0 ]
do
case $1 in
#set the variables based on what option was used
-u)TRCASE=upper
EXT=".UC"
OPT=yes
shift
;;
-l)TRCASE=lower
EXT=".LC"
OPT=yes
shift
;;
-help) echo "convert a file(s) to uppercase from lowercase"
echo "convert a file(s) from lowercase to uppercase"
echo "will convert all characters according to the sepcified command option."
echo "where option is"
echo "-l Convert to lowercase"
echo "-u Convert to uppercase"
echo "The original file(s) is not touched. A new file(s)"
echo "will be created with either a .UC or .LC extension"
echo "usage: $0 -[l|u] file [file..]"
exit 0
;;
-*) echo "usage: `basename $0` -[l|u] file [file..]"
exit 1
;;
*) # collect the files to process
if [ -f $1 ]
then
# add the filenames to a variable list
FILES=$FILES" "$1
else
echo "`basename $0` : Error cannot find the file $1"
fi
shift
;;
esac
done
if [ "$OPT" = "no" ]
then
echo "`basename $0`: Error you need to specify an option. No action taken"
echo "`basename` --help"
exit 1
fi
# now read in all the file(s)
# use the variable LOOP, I just love the word LOOP
for LOOP in $FILES
do
case $TRCASE in
lower) cat $LOOP|tr "[a-z]" "[A-Z]" >$LOOP$EXT
if [ $? != 0 ]
then
error_msg $LOOP
else
echo "Converted file called $LOOP$EXT"
fi
;;
upper) cat $LOOP|tr "[A-Z]" "[a-z]" > $LOOP$EXT
if [ $? != 0 ]
then
error_msg $LOOP
else
echo "Converted file called $LOOP$EXT"
fi
;;
esac
done

!#/bin/sh
# tr_case
# convert files to either  upper or lower case
FILES=""
TRCASE=""
EXT=""
OPT=no
# gets called when a conversion fails
error_msg()
{
_FILENAME=$1
echo "`basename $0`: Error the conversion failed on $_FILENAME"
}
if [ $# -eq 0 ]
then
echo "For more info try `basename $0` --help"
exit 1
fi
while [ $# -gt 0 ]
do
case $1 in
#set the variables based on what option was used
-u)TRCASE=upper
EXT=".UC"
OPT=yes
shift
;;
-l)TRCASE=lower
EXT=".LC"
OPT=yes
shift
;;
-help) echo "convert a file(s) to uppercase from lowercase"
echo "convert a file(s) from lowercase to uppercase"
echo "will convert all characters according to the sepcified command option."
echo "where option is"
echo "-l Convert to lowercase"
echo "-u Convert to uppercase"
echo "The original file(s) is not touched. A new file(s)"
echo "will be created with either a .UC or .LC extension"
echo "usage: $0 -[l|u] file [file..]"
exit 0
;;
-*) echo "usage: `basename $0` -[l|u] file [file..]"
exit 1
;;
*) # collect the files to process
if [ -f $1 ]
then
# add the filenames to a variable list
FILES=$FILES" "$1
else
echo "`basename $0` : Error cannot find the file $1"
fi
shift
;;
esac
done
if [ "$OPT" = "no" ]
then
echo "`basename $0`: Error you need to specify an option. No action taken"
echo "`basename` --help"
exit 1
fi
# now read in all the file(s)
# use the variable LOOP, I just love the word LOOP
for LOOP in $FILES
do
case $TRCASE in
lower) cat $LOOP|tr "[a-z]" "[A-Z]" >$LOOP$EXT
if [ $? != 0 ]
then
error_msg $LOOP
else
echo "Converted file called $LOOP$EXT"
fi
;;
upper) cat $LOOP|tr "[A-Z]" "[a-z]" > $LOOP$EXT
if [ $? != 0 ]
then
error_msg $LOOP
else
echo "Converted file called $LOOP$EXT"
fi
;;
esac
done

getopts命��o

Shell代码

#!/bin/sh
#getopts1
#set the vars
ALL=false
HELP=false
FILE=false
VERBROSE=false
while getopts ahfgv OPTION
do
case $OPTION in
a)ALL=true
echo "ALL is $ALL"
;;
h)HELP=true
echo "HELP is $HELP"
;;
f)FILE=true
echo "FILE is $FILE"
;;
v)VERBOSE=true
echo "VERROSE is $VERROSE"
;;
esac
done

#!/bin/sh
#getopts1
#set the vars
ALL=false
HELP=false
FILE=false
VERBROSE=false
while getopts ahfgv OPTION
do
case $OPTION in
a)ALL=true
echo "ALL is $ALL"
;;
h)HELP=true
echo "HELP is $HELP"
;;
f)FILE=true
echo "FILE is $FILE"
;;
v)VERBOSE=true
echo "VERROSE is $VERROSE"
;;
esac
done

Shell代码

/home/l/g/tomotoboy/getopts >getopts1 -a
ALL is true
/home/l/g/tomotoboy/getopts >getopts1 -v
VERROSE is
/home/l/g/tomotoboy/getopts >getopts1 -v -a -h
VERROSE is
ALL is true
HELP is true

/home/l/g/tomotoboy/getopts >getopts1 -a
ALL is true
/home/l/g/tomotoboy/getopts >getopts1 -v
VERROSE is
/home/l/g/tomotoboy/getopts >getopts1 -v -a -h
VERROSE is
ALL is true
HELP is true

getopts一般格式�ؓ�Q?
getopts option_string variable
在上�q�C��子中使用脚本�Q?
while getopts ahfgv OPTION
可以看出while循环用于��d��命��o行，option_string为指定的5个选项�Q? a�Q? h�Q? f�Q? g�Q? v�Q?脚本中variable为OPTION。注意这里�ƈ没有用连字符指定每一单个选项�?

使用getopts指定变量取�?/strong>
有时有必要在脚本中指定命令行选项取倹{��getopts为此提供了一�U�方式，卛_��option_string中将一个冒��h��在选项后。例如：
getopts ahfvc: OPTION
上面一行脚本指出，选项 a、h、f、v可以不加实际��D��行传递，而选项 c必须取倹{��用选项取值时�Q�必��M��用变�?OPTARG保存该倹{��如果试图不取��g��递此选项�Q�会�q�回一个错误信息。错误信息提�C��ƈ不明��，因此可以用自��q��反馈信息屏蔽它，�Ҏ(gu��)��如下�Q?
��冒��h��在option_string开始部分�?

Shell代码

while getopts :ahfgvc:  OPTION

while getopts :ahfgvc: OPTION

Shell代码

#!/bin/sh

#getopts1

#set the vars

ALL=false

HELP=false

FILE=false

VERBROSE=false

COPIES=0 #the value for the -c option is set to zero

while getopts :ahfgvc: OPTION

do

  case $OPTION in

  a)ALL=true

    echo "ALL is $ALL"

    ;;

  h)HELP=true

    echo "HELP is $HELP"

    ;;

  f)FILE=true

    echo "FILE is $FILE"

    ;;

  v)VERBOSE=true

    echo "VERROSE is $VERROSE"

    ;;

  c)COPIES=$OPTARG

    echo "COPIES is $COPIES"

    ;;

  \?) #usage stagement

    echo "`basename $0` -[a h f v] -[c value] file" >&2

    ;;

esac

done

#!/bin/sh #getopts1 #set the vars ALL=false HELP=false FILE=false VERBROSE=false COPIES=0 #the value for the -c option is set to zero while getopts :ahfgvc: OPTION do case $OPTION in a)ALL=true echo "ALL is $ALL" ;; h)HELP=true echo "HELP is $HELP" ;; f)FILE=true echo "FILE is $FILE" ;; v)VERBOSE=true echo "VERROSE is $VERROSE" ;; c)COPIES=$OPTARG echo "COPIES is $COPIES" ;; \?) #usage stagement echo "`basename $0` -[a h f v] -[c value] file" >&2 ;; esac done

Shell代码

/home/l/g/tomotoboy/getopts >chmod 755 getopts2

/home/l/g/tomotoboy/getopts >getopts2 -c hello

COPIES is hello

/home/l/g/tomotoboy/getopts >getopts2 -h -c hello

HELP is true

COPIES is hello

/home/l/g/tomotoboy/getopts >chmod 755 getopts2 /home/l/g/tomotoboy/getopts >getopts2 -c hello COPIES is hello /home/l/g/tomotoboy/getopts >getopts2 -h -c hello HELP is true COPIES is hello

讉K��取值方�?/strong>
getopts的一�U�功能是�q�行后台脚本。这样可以��用户加入选项�Q�指定不同的��带讑֤�以备份数据。��用getopts实现此�Q务的基本框架如下�Q?

Shell代码

#!/bin/sh

QUITE=n

DEVICE=awa

LOGFILE=/tmp/logbackup

usage()

{

echo "Usage: `basename $0` -d [device] -l [logfile] -q"

exit 1



}

if [ $# = 0 ]

then

  usage

fi



while getopts :qd:l: OPTION

do

  case $OPTION in

  q) QUIET=y

     LOGFILE="/tmp/backup.log"

     ;;

  d) DEVICE=$OPTARG

     ;;

  l) LOGFILE=$OPTARG

     ;;

  \?)usage

     ;;

   esac

done

echo "you chose the following options...I can now process these"

echo "Quite = $QUIET $DEVICE $LOGFILE"

Gavin.lee 2009-11-29 12:10 发表评论

shell函数

Gavin.lee — Sun, 29 Nov 2009 04:09:00 GMT

函数�׃��部分�l�成�Q?

函数标题�?
函数体�?

标题是函数名。函��C��是函数内的命令集合。标题名应该唯一�Q�如果不是，��会��h��l�，因�ؓ脚本在查看调用脚本前��首先搜索函数调用相应的 s h e l l�?
定义函数的格式�ؓ�Q?

Shell代码

函数名（�Q?

{

命��o1

. . .

}

或�?

function 函数名（�Q?

{   ...

}

函数名（�Q? { 命��o1 . . . } 或�? function 函数名（�Q? { ... }

两者方式都可行。如果愿意，可在函数名前加上关键字function�Q�这取决于��用者�?

创徏函数文�g
下面创徏包容函数的函数文件�ƈ��之载入shell�Q�进行测试，再做改动�Q�之后再重新载入�?
函数文�g名�ؓfunctions.main�Q�内容如�?

Shell代码

#!/bin/sh

#functions.main

#

#findit: this is front end for the basic find command

findit() {

#findit

if [ $# -lt 1 ]; then

echo "usage : findit file"

return 1;

fi

find . -name $1 -print

}

#!/bin/sh #functions.main # #findit: this is front end for the basic find command findit() { #findit if [ $# -lt 1 ]; then echo "usage : findit file" return 1; fi find . -name $1 -print }
定位文�g
定位文�g格式为：
. /pahname/filename
现在文�g已经创徏好了�Q�要��之载入shell�Q�试键入�Q?
$. functions.main
如果�q�回信息file not found�Q�再试：
$. /functions.main
此即<�?gt; <�I�格> <斜线> <文�g�?gt;�Q�现在文件应该已载入shell。如果仍有错误，则应该仔�l�检查是否键入了完整路径�?

��查蝲入函�?
使用set命��o��保函数已蝲入。set命��o��在shell中显�C�所有的载入函数�?

Shell代码

/home/l/g/tomotoboy/function >. function.main

/home/l/g/tomotoboy/function >set

……

_=function.main

findit ()

{

    if [ $# -lt 1 ]; then

        echo "usage : findit file";

        return 1;

    fi;

    find . -name $1 -print

}

/home/l/g/tomotoboy/function >. function.main /home/l/g/tomotoboy/function >set …… _=function.main findit () { if [ $# -lt 1 ]; then echo "usage : findit file"; return 1; fi; find . -name $1 -print }
执行shell函数
要执行函敎ͼ��单地键入函数名即可。这里是带有一个参数的 findit函数�Q�参数是某个文�g

Shell代码

/home/l/g/tomotoboy/function >cd .

/home/l/g/tomotoboy/function >cd ..

/home/l/g/tomotoboy >findit sed.txt

./testdirec/sed.txt

./sed.txt

/home/l/g/tomotoboy/function >cd . /home/l/g/tomotoboy/function >cd .. /home/l/g/tomotoboy >findit sed.txt ./testdirec/sed.txt ./sed.txt

删除shell函数
现在对函数做一些改动。首先删除函敎ͼ�使其对shell不可利用。��用unset命��o完成此功能。删除函数时unset命��o格式为：
unset function_name
$unset findit
如果现在键入set命��o�Q�函数将不再昄��?

Shell代码

/home/l/g/tomotoboy >unset findit

/home/l/g/tomotoboy >set

……

_=findit

/home/l/g/tomotoboy >findit sed.txt

-bash: findit: command not found

/home/l/g/tomotoboy >unset findit /home/l/g/tomotoboy >set …… _=findit /home/l/g/tomotoboy >findit sed.txt -bash: findit: command not found

再次定位函数

Shell代码

/home/l/g/tomotoboy >. function/function.main

/home/l/g/tomotoboy >findit sed.txt

./testdirec/sed.txt

./sed.txt

/home/l/g/tomotoboy >. function/function.main /home/l/g/tomotoboy >findit sed.txt ./testdirec/sed.txt ./sed.txt

如果函数��从��试�l�果中反馈输出，那么使用替换命��o可保存结果。函数调用的替换格式为：
variable_name = variable_name
函数function_name输出被设�|�到变量variable_name中�?

Shell代码

char_name(){

# char_name

# to call: char_name string

# assign the argument across to new variable

_LETTER_ONLY=$1

# user awk to test for character only!

_LETTER_ONLY=`echo $1|awk '{if ($0~/[^a-z A-Z]/) print 1}'`

if [ "$_LETTER_ONLY" != "" ]

then

    # oops  errors

    return 1

else

    # constains only chars

    return 0

fi

}

char_name(){ # char_name # to call: char_name string # assign the argument across to new variable _LETTER_ONLY=$1 # user awk to test for character only! _LETTER_ONLY=`echo $1|awk '{if ($0~/[^a-z A-Z]/) print 1}'` if [ "$_LETTER_ONLY" != "" ] then # oops errors return 1 else # constains only chars return 0 fi }

Shell代码

if char_name $F_NAME; then

echo "OK"

else

  echo "ERROR"

fi

if char_name $F_NAME; then echo "OK" else echo "ERROR" fi
��试一�?

Shell代码

/home/l/g/tomotoboy/function >char_name hello

/home/l/g/tomotoboy/function >echo $?

0

/home/l/g/tomotoboy/function >char_name hello /home/l/g/tomotoboy/function >echo $? 0
注意^�W�号的��用，当直接用在第一个括号里�Q�意指否定或不匹配括号里内容。[^a-z A-Z] 匚w��M��非字母型字符�Q�而[^0-9]匚w��M��非数字型字符�?

Gavin.lee 2009-11-29 12:09 发表评论

Gavin.lee — Sun, 29 Nov 2009 04:08:00 GMT

当你在终端或控制台工作时�Q�可能不希望�׃��q�行一个作业而占住了屏幕�Q�因为可能还有更重要的事情要做，比如阅读�?sh��)子邮�g。对于密集访问磁盘的�q�程�Q�你可能希望它能够在每天的非负荷高峰旉��D�运行。�ؓ了�ɘq�些�q�程能够在后台运行，也就是说不在�l�端屏幕上运行，有几�U�选择�Ҏ(gu��)��可供使用�Q?

讄��crontab文�g�Q��ƈ用它来提交作业�?
使用at命��o来提交作业�?
在后台提交作业�?
使用nohup命��o提交作业�?

名词解释�Q?

cron�pȝ��调度�q�程。可以��用它在每天的非高峰负��h��间段�q�行作业�Q�或在一周或一月中的不同时�D�运行�?
at命��o。��用它在一个特定的旉��q�行一些特�D�的作业�Q�或在晚一些的非负荷高峰时间段或高峰负��h��间段�q�行�?
& 使用它在后台�q�行一个占用时间不长的�q�程�?
Nohup 使用它在后台�q�行一个命令，即��在用户退出时也不受媄响�?

一个�D一个例�?
crontab
用crontab提交一个�Q务在每天晚上7点对zhangwanzhi说i love you

Shell代码

/home/l/g/tomotoboy >touch tomotoboycron

/home/l/g/tomotoboy >cat > tomotoboycron

0 19 * * * echo "I love zhangwanzhi"

/home/l/g/tomotoboy >crontab tomotoboycron

cron may not be running - call your system administrator

/home/l/g/tomotoboy >crontab -l

0 19 * * * echo "I love zhangwanzhi"

/home/l/g/tomotoboy >touch tomotoboycron /home/l/g/tomotoboy >cat > tomotoboycron 0 19 * * * echo "I love zhangwanzhi" /home/l/g/tomotoboy >crontab tomotoboycron cron may not be running - call your system administrator /home/l/g/tomotoboy >crontab -l 0 19 * * * echo "I love zhangwanzhi"

删除crontab 文�g

Shell代码

/home/l/g/tomotoboy >crontab -r

cron may not be running - call your system administrator

/home/l/g/tomotoboy >crontab -l

crontab: can't open your crontab file.

/home/l/g/tomotoboy >crontab -r cron may not be running - call your system administrator /home/l/g/tomotoboy >crontab -l crontab: can't open your crontab file.

恢复丢失的crontab文�g
如果不小心误删了crontab文�g�Q�假设你在自��q��$HOME目录下还有一个备份，那么可以��其拯��?var/spool/cron/�Q�其�?lt;username>是用户名。如果由于权限问题无法完成拷贝，可以用：

Shell代码

$ crontab

$ crontab

现在我们来恢复tomotoboycron

Shell代码

/home/l/g/tomotoboy >crontab tomotoboycron

cron may not be running - call your system administrator

/home/l/g/tomotoboy >crontab -l

0 19 * * * echo "I love zhangwanzhi"

/home/l/g/tomotoboy >crontab tomotoboycron cron may not be running - call your system administrator /home/l/g/tomotoboy >crontab -l 0 19 * * * echo "I love zhangwanzhi"

at
在命令提交一分钟后执�?

Shell代码

/home/l/g/tomotoboy >ls -l|grep "tomotoboy"|at now +1 minute

cron may not be running - call your system administrator

commands will be executed using /bin/bash

job 1249815115.a at Sun Aug  9 18:51:55 2009

/home/l/g/tomotoboy >ls -l|grep "tomotoboy"|at now +1 minute cron may not be running - call your system administrator commands will be executed using /bin/bash job 1249815115.a at Sun Aug 9 18:51:55 2009

列出已经提交的at��d��Q?

Shell代码

/home/l/g/tomotoboy >at -l

1249815115.a    Sun Aug  9 18:51:55 2009

1249813233.a    Sun Aug  9 18:20:33 2009

1249813261.a    Sun Aug  9 18:21:01 2009

/home/l/g/tomotoboy >at -l 1249815115.a Sun Aug 9 18:51:55 2009 1249813233.a Sun Aug 9 18:20:33 2009 1249813261.a Sun Aug 9 18:21:01 2009

使用atrm删除一个�Q务：

Shell代码

/home/l/g/tomotoboy >atrm 1249815115.a

cron may not be running - call your system administrator

1249815115.a: removed

/home/l/g/tomotoboy >at -l

1249813233.a    Sun Aug  9 18:20:33 2009

1249813261.a    Sun Aug  9 18:21:01 2009

/home/l/g/tomotoboy >atrm 1249815115.a cron may not be running - call your system administrator 1249815115.a: removed /home/l/g/tomotoboy >at -l 1249813233.a Sun Aug 9 18:20:33 2009 1249813261.a Sun Aug 9 18:21:01 2009

&和nohup
在后台运行echo "I love you zhangwanzhi" �Q�用户退出时不终止：

Shell代码

/home/l/g/tomotoboy >nohup echo "I love you zhangwanzhi" &

[1] 20784

/home/l/g/tomotoboy >Sending output to nohup.out

/home/l/g/tomotoboy >cat nohup.out

Ilove you zhangwanzhi

Gavin.lee 2009-11-29 12:08 发表评论

控制��结构——until、while、break、continue

Gavin.lee — Sun, 29 Nov 2009 04:07:00 GMT

until循环
条�g�?为真�Q?为假
until循环执行一�p�d��命��o直至条�g为真时停止�?until循环与while循环在处理方式上刚好相反。一般while循环优于until循环�Q�但在某些时候—也只是极少数情况下�Q�until循环更加有用�?
until循环格式为：

Shell代码

until  条�g

do

    命��o1

    . . .

done

until 条�g do 命��o1 . . . done
条�g可�ؓ��L��试条�g�Q�测试发生在循环末尾�Q�因此��@环至��执行一�ơ—请注意�q�一�?
监视文�g
下面例子中，until循环不断挂�v做睡眠，直至文�gprocess.LCK 被删除。文件删除后�Q�脚本进入正常处理过�E��?

Shell代码

/home/l/g/tomotoboy/until >ls

until_lck  untilwho

/home/l/g/tomotoboy/until >[ -f untilwho ]

/home/l/g/tomotoboy/until >echo $?

0

/home/l/g/tomotoboy/until >[ ! -f untilwho ]

/home/l/g/tomotoboy/until >echo $?

1

/home/l/g/tomotoboy/until >rm untilwho

/home/l/g/tomotoboy/until >[ ! -f untilwho ]

/home/l/g/tomotoboy/until >echo $?

0



#!/bin/sh

#until_lck

touch `pwd`/process.LCK

LOCK_FILE=`pwd`/process.LCK

until [ ! -f $LOCK_FILE ]

do

     sleep 1

done

echo "file deleted"

/home/l/g/tomotoboy/until >ls until_lck untilwho /home/l/g/tomotoboy/until >[ -f untilwho ] /home/l/g/tomotoboy/until >echo $? 0 /home/l/g/tomotoboy/until >[ ! -f untilwho ] /home/l/g/tomotoboy/until >echo $? 1 /home/l/g/tomotoboy/until >rm untilwho /home/l/g/tomotoboy/until >[ ! -f untilwho ] /home/l/g/tomotoboy/until >echo $? 0 #!/bin/sh #until_lck touch `pwd`/process.LCK LOCK_FILE=`pwd`/process.LCK until [ ! -f $LOCK_FILE ] do sleep 1 done echo "file deleted"

查找tomotoboy有没有登录，登陆后给自己发个邮�g

Shell代码

/home/l/g/tomotoboy/until >cat untilwho

#!/bin/sh

#until_who

IS_TOMOTOBOY=`who | grep tomotoboy`

until [  "$IS_TOMOTOBOY" ]

do

    sleep 5

done

echo "Wtch it. tomotoboy in " | mail tomotoboy

/home/l/g/tomotoboy/until >cat untilwho #!/bin/sh #until_who IS_TOMOTOBOY=`who | grep tomotoboy` until [ "$IS_TOMOTOBOY" ] do sleep 5 done echo "Wtch it. tomotoboy in " | mail tomotoboy

while循环
while循环用于不断执行一�p�d��命��o�Q�也用于从输入文件中��d��数据�Q�其格式为：

Shell代码

while  命��o

do

命��o1

命��o2

. . .

done

while 命��o do 命��o1 命��o2 . . . done
虽然通常只��用一个命令，但在 while和do之间可以攑և�个命令。命令通常用作��试条�g。只有当命��o的退出状态�ؓ 0�Ӟ��do和done之间命��o才被执行�Q�如果退出状态不�?0�Q�则循环�l�止�?

Shell代码

#!/bin/sh

#whilecount

COUNT=0

while [ $COUNT -lt 5 ]

do

  echo "$COUNT"

  COUNT=`expr $COUNT + 1`

done



/home/l/g/tomotoboy >whilecount

0

1

2

3

4

#!/bin/sh #whilecount COUNT=0 while [ $COUNT -lt 5 ] do echo "$COUNT" COUNT=`expr $COUNT + 1` done /home/l/g/tomotoboy >whilecount 0 1 2 3 4

��L��?

Shell代码

#!/bin/sh

#whileread

while read LINE

do

  echo "$LINE"

done < sed.txt

#!/bin/sh #whileread while read LINE do echo "$LINE" done < sed.txt

break
break命��o允许跛_��循环。break通常在进行一些处理后退出��@环或 case语句。如果是在一个嵌入��@环里�Q�可以指定蟩出的循环个数。例如如果在两层循环内，�?break刚好跛_��整个循环�?
跛_��case语句
下面的例子中�Q�脚本进入死循环直至用户输入数字大于 5。要跛_��q�个循环�Q�返回到shell提示�W�下�Q�break使用脚本如下�Q?

Shell代码

#!/bin/sh

#breakout

#while : means loop forever

while :

do

   echo -n "Enter any number [1..5]: "

   read ANS

   case $ANS in

   1|2|3|4|5) echo " great you entered a number between 1 and 5"

   ;;

   *)echo "Wrong number..bye"

   break

  ;;

esac

done

#!/bin/sh #breakout #while : means loop forever while : do echo -n "Enter any number [1..5]: " read ANS case $ANS in 1|2|3|4|5) echo " great you entered a number between 1 and 5" ;; *)echo "Wrong number..bye" break ;; esac done

Shell代码

/home/l/g/tomotoboy >breakout

-n Enter any number [1..5]:

3

great you entered a number between 1 and 5

-n Enter any number [1..5]:

6

Wrong number..bye

/home/l/g/tomotoboy >breakout -n Enter any number [1..5]: 3 great you entered a number between 1 and 5 -n Enter any number [1..5]: 6 Wrong number..bye

continue
continue命��o�c�M��于break命��o�Q�只有一炚w��要差别，它不会蟩出��@环，只是跌��q�个循环步�?

Gavin.lee 2009-11-29 12:07 发表评论

控制��结构——for

Gavin.lee — Sun, 29 Nov 2009 04:06:00 GMT

for循环
for 变量�?in 列表
do
       命��o 1
       命��o 2
done
当变量值在列表里，for循环��x��行一�ơ所有命令，使用变量名访问列表中取倹{��命令可��Z�Q何有效的shell命��o和语句。变量名��Z�Q何单词。in列表用法是可选的�Q�如果不用它�Q?for循环使用命��o行的位置参数。in列表可以包含替换、字�W�串和文件名�Q�下面看一些例子�?

Shell代码

/home/l/g/tomotoboy/for >cat fortest

#!/bin/sh

#for_i

for loop in 1 2 3 4 5 6

do

    echo $loop

done



#forlist

for loop in "orange red blue grey"

do

   echo $loop

done



#forls

for loop in `ls`

do

     echo $loop

done





#forparam

for params

do

     echo "you supplied $params as command line option"

     echo $params

done



for params in "$@"

do

     echo "you supplied $params as command line option"

     echo $params

done



#forcommand

for loop

do

      find `pwd` -name $loop -print

done





/home/l/g/tomotoboy/for >fortest fortest

1

2

3

4

5

6

orange red blue grey

fortest

you supplied fortest as command line option

fortest

you supplied fortest as command line option

fortest

/home/l/g/tomotoboy/for >cat fortest #!/bin/sh #for_i for loop in 1 2 3 4 5 6 do echo $loop done #forlist for loop in "orange red blue grey" do echo $loop done #forls for loop in `ls` do echo $loop done #forparam for params do echo "you supplied $params as command line option" echo $params done for params in "$@" do echo "you supplied $params as command line option" echo $params done #forcommand for loop do find `pwd` -name $loop -print done /home/l/g/tomotoboy/for >fortest fortest 1 2 3 4 5 6 orange red blue grey fortest you supplied fortest as command line option fortest you supplied fortest as command line option fortest

使用for循环�q�接服务�?
因�ؓfor循环可以处理列表中的取��|��现设变量为网�l�服务器名称�Q��ƈ使用for循环�q�接每一服务器�?

Shell代码

#!/bin/sh

#forping

HOSTS="sina.com cqu.edu.cn baidu.com"

for loop in $HOSTS

do

     ping -c 2 $loop

done

#!/bin/sh #forping HOSTS="sina.com cqu.edu.cn baidu.com" for loop in $HOSTS do ping -c 2 $loop done
多文件�{�?
匚w��所有以.sed�l�尾文�g�q�将其�{换�ؓ大写。这里��用了 l s和cat命��o。l s用于查询出相��x��Ӟ��cat用于��之��道输出至trr命��o。目标文件扩展名�?UC�Q�注意在for循环中��用l s命��o时反引号的用法�?

Shell代码

#!/bin/sh

#forstr

for files in `ls *.sed`

do

    cat $files |tr "[a-z]"  "[A-Z]" >$files.UC

done



/home/l/g/tomotoboy >cat change.sed

#!/bin/sed -f

#change.sed

/tomotoboy/ c\

I love China,Ilove Wanzhi.

/home/l/g/tomotoboy >ls *.UC

append.sed.UC  change.sed.UC

/home/l/g/tomotoboy >cat change.sed.UC

#!/BIN/SED -F

#CHANGE.SED

/TOMOTOBOY/ C\

I LOVE CHINA,ILOVE WANZHI.

#!/bin/sh #forstr for files in `ls *.sed` do cat $files |tr "[a-z]" "[A-Z]" >$files.UC done /home/l/g/tomotoboy >cat change.sed #!/bin/sed -f #change.sed /tomotoboy/ c\ I love China,Ilove Wanzhi. /home/l/g/tomotoboy >ls *.UC append.sed.UC change.sed.UC /home/l/g/tomotoboy >cat change.sed.UC #!/BIN/SED -F #CHANGE.SED /TOMOTOBOY/ C\ I LOVE CHINA,ILOVE WANZHI.

多sed删除操作
下面的例子中�Q�sed用于删除所有空文�g�Q��ƈ��输出导至以 . HOLD.为扩展名的新文�g�Q�mv��这些文件移臛_��始文件中�?

Shell代码

#!/bin/sh

#forsed

for files in `ls *.sed`

do

   sed -e "/^$/d" $files > $files.HOLD

   mv $files.HOLD $files

done

#!/bin/sh #forsed for files in `ls *.sed` do sed -e "/^$/d" $files > $files.HOLD mv $files.HOLD $files done

循环计数
前面讨论expr时指出，循环时如果要加入计数�Q��用此命��o。下面��?l s在for循环中列出文件及其数目�?

Shell代码

/home/l/g/tomotoboy >cat forcount

#!/bin/sh

#forcount

count=0

for files in *

do

  count=`expr $count + 1`

done

echo "There are $count files in `pwd` we need to process"

/home/l/g/tomotoboy >cat forcount #!/bin/sh #forcount count=0 for files in * do count=`expr $count + 1` done echo "There are $count files in `pwd` we need to process"

Gavin.lee 2009-11-29 12:06 发表评论

控制��结构——if then else

Gavin.lee — Sun, 29 Nov 2009 04:05:00 GMT

if then else语句

Shell代码

If  条�g1    //如果条�g1为真

Then         //那么

命��o1       //执行命��o1

elif  条�g2    //如果条�g1不成�?

then           //那么

命��o2        //执行命��o2

else           //如果条�g1�Q?/span>2均不成立

命��o3       //那么执行命��o3

fi             //完成

If 条�g1 //如果条�g1为真 Then //那么命��o1 //执行命��o1 elif 条�g2 //如果条�g1不成�? then //那么命��o2 //执行命��o2 else //如果条�g1�Q?均不成立命��o3 //那么执行命��o3 fi //完成

��单的if语句
最普通的if语句是：
if条�g
then 命��o
if
使用if语句�Ӟ��必须��then部分攑֜�新行�Q�否则会产生错误。如果要不分行，必须使用命��o分隔�W�。本

书其余部分将采取�q�种形式。现在简�?if语句变�ؓ�Q?
if 条�g�Q�then
命��o
if

Shell代码

/home/l/g/tomotoboy >cat iftest

#!/bin/sh

#iftest

#this is a comment line,all comment lines start with a#

if [ "12" -lt "14" ]

then

#yes 12 is less than 14

echo  "Yes, 12 is less than 14"

fi



/home/l/g/tomotoboy >chmod u+x iftest

/home/l/g/tomotoboy > ./iftest

Yes, 12 is less than 14

/home/l/g/tomotoboy >cat iftest #!/bin/sh #iftest #this is a comment line,all comment lines start with a# if [ "12" -lt "14" ] then #yes 12 is less than 14 echo "Yes, 12 is less than 14" fi /home/l/g/tomotoboy >chmod u+x iftest /home/l/g/tomotoboy > ./iftest Yes, 12 is less than 14
变量值测�?
不必拘惔于变量或数值测试，也可以测知系�l�命令是否成功返回。对 grep使用if语句扑և�grep是否成功

�q�回信息。下面的例子�?grep用于查看tomotoboy是否在数据文件sed.txt中，注意'tomotoboy'用于�_?

��匹配�?

Shell代码

/home/l/g/tomotoboy >cat grepif

#!/bin/sh

#grep if

if grep 'tomotoboy' sed.txt >/dev/null 2>&1

then

echo "tomotoboy is  in the file"

else

echo "tomotoboy is not in the file"

fi



/home/l/g/tomotoboy >./grepif

tomotoboy is  in the file

/home/l/g/tomotoboy >cat grepif #!/bin/sh #grep if if grep 'tomotoboy' sed.txt >/dev/null 2>&1 then echo "tomotoboy is in the file" else echo "tomotoboy is not in the file" fi /home/l/g/tomotoboy >./grepif tomotoboy is in the file

用变量测试grep输出
正像前面看到的，可以用grep作字�W�串操作。下面的脚本中，用户输入一个名字列表，grep在变量中查找�Q�要求其查找指定字符�?

Shell代码

/home/l/g/tomotoboy >cat grepstr

#!/bin/sh

#grepstr

echo -n "Enter a piece of text file:"

read TEXT

echo -n "Enter a string to query: "

read QUERY

if grep $QUERY $TEXT >/dev/null 2>&1

then

   echo "$QUERY is in $TEXT"

   #could do some processing here...

else

   echo "$QUERY is not in  $TEXT"

fi



/home/l/g/tomotoboy >./grepstr

-n Enter a piece of text file:

sed.txt

-n Enter a string to query:

tomotoboy

tomotoboy is in sed.txt

/home/l/g/tomotoboy >cat grepstr #!/bin/sh #grepstr echo -n "Enter a piece of text file:" read TEXT echo -n "Enter a string to query: " read QUERY if grep $QUERY $TEXT >/dev/null 2>&1 then echo "$QUERY is in $TEXT" #could do some processing here... else echo "$QUERY is not in $TEXT" fi /home/l/g/tomotoboy >./grepstr -n Enter a piece of text file: sed.txt -n Enter a string to query: tomotoboy tomotoboy is in sed.txt

文�g拯��输出��?
下面��试文�g拯��是否正常�Q�如�?cp命��o�q�没有拷贝文件myfile到myfile.bak�Q�则打印错误信息。注意错误信息中` basename $0`打印脚本名。如果脚本错误退出，一个好�?f��n)惯是显�C��本名�q�将之定向到标准错误中。用户应该知道��生错误的脚本名�?

Shell代码

/home/l/g/tomotoboy >chmod u+x ifcp

/home/l/g/tomotoboy >ifcp

cp: cannot access myfile

ifcp: error could not copy the file

/home/l/g/tomotoboy >cat ifcp

#!/bin/sh

#ifcp

if cp myfile myfile.bak; then

echo "good copy"

else

echo "`basename $0`: error could not copy the file" >&2

fi

/home/l/g/tomotoboy >touch myfile

/home/l/g/tomotoboy >ifcp

good copy

/home/l/g/tomotoboy >

/home/l/g/tomotoboy >chmod u+x ifcp /home/l/g/tomotoboy >ifcp cp: cannot access myfile ifcp: error could not copy the file /home/l/g/tomotoboy >cat ifcp #!/bin/sh #ifcp if cp myfile myfile.bak; then echo "good copy" else echo "`basename $0`: error could not copy the file" >&2 fi /home/l/g/tomotoboy >touch myfile /home/l/g/tomotoboy >ifcp good copy /home/l/g/tomotoboy >

当前目录��试
当运行一些管理脚本时�Q�可能要在根目录下运行它�Q�特别是�U�d��某种全局文�g或进行权限改变时。一个简单的��试可以��L(f��ng)��是否�q�行在根目录下。下面脚本中变量DIRECTORY使用当前目录的命令替换操作，然后此变量��g�� " / "字符串比较（/为根目录�Q?。如果变量��g��字符串不�{�，则用户退��本，退出状态�ؓ1意味错误信息产生�?

Shell代码

/home/l/g/tomotoboy >ifpwd

You need to be in the root directory not /home/l/g/tomotoboy to run this script

/home/l/g/tomotoboy >cd /etc

/etc >cd /

/ >/home/l/g/tomotoboy/ifpwd

/ >cat ifpwd

cat: cannot open ifpwd

/ >cat /home/l/g/tomotoboy/ifpwd

#!/bin/sh

#ifpwd

DIRECTORY=`pwd`

#grab the current directory

if [ "$DIRECTORY" != "/" ];then

#is it the root directory?

#no ,the direct output to standard  error,which is the screen by default.

echo "You need to be in the root directory not $DIRECTORY to run this script" >&2

#exit with a value of 1, an error

exit 1

fi

/home/l/g/tomotoboy >ifpwd You need to be in the root directory not /home/l/g/tomotoboy to run this script /home/l/g/tomotoboy >cd /etc /etc >cd / / >/home/l/g/tomotoboy/ifpwd / >cat ifpwd cat: cannot open ifpwd / >cat /home/l/g/tomotoboy/ifpwd #!/bin/sh #ifpwd DIRECTORY=`pwd` #grab the current directory if [ "$DIRECTORY" != "/" ];then #is it the root directory? #no ,the direct output to standard error,which is the screen by default. echo "You need to be in the root directory not $DIRECTORY to run this script" >&2 #exit with a value of 1, an error exit 1 fi

文�g权限��试
可以用i f语句��试文�g权限�Q�下面简单测试文件sed.txt是否可写

Shell代码

/home/l/g/tomotoboy >ifwr sed.txt

You can write to sed.txt

/home/l/g/tomotoboy >cat ifwr

#!/bin/sh

#ifwr

if [ ! -w "$1" ]; then

  echo "You cannot write to $1" >&2

else

  echo "You can write to $1"

fi

/home/l/g/tomotoboy >ifwr sed.txt You can write to sed.txt /home/l/g/tomotoboy >cat ifwr #!/bin/sh #ifwr if [ ! -w "$1" ]; then echo "You cannot write to $1" >&2 else echo "You can write to $1" fi

��试传递到脚本中的参数
if语句可用来测试传入脚本中参数的个数。��用特定变�?#�Q�表�C��用参数的个数。可以测试所需参数个数与调用参��C��数是否相�{�。以下测试确保脚本有三个参数。如果没有，则返回一个可用信息到标准错误�Q�然后代码退出�ƈ昄��退出状态。如果参数数目等�?�Q�则昄��所有参数�?

Shell代码

/home/l/g/tomotoboy >cat ifparam

#!/bin/sh

#ifparam

if [ $# -lt 3 ]; then

#less than 3 parameters called,echo  a usage message and exit

echo "Usage: `basename $0` arg1 arg2 arg3" >&2

exit

fi

#good ,receive 3 params, let's echo them

echo "arg1: $1"

echo "arg2: $2"

echo "arg3: $3"

/home/l/g/tomotoboy >ifparam yang shi hai

arg1: yang

arg2: shi

arg3: hai

/home/l/g/tomotoboy >cat ifparam #!/bin/sh #ifparam if [ $# -lt 3 ]; then #less than 3 parameters called,echo a usage message and exit echo "Usage: `basename $0` arg1 arg2 arg3" >&2 exit fi #good ,receive 3 params, let's echo them echo "arg1: $1" echo "arg2: $2" echo "arg3: $3" /home/l/g/tomotoboy >ifparam yang shi hai arg1: yang arg2: shi arg3: hai

军_��脚本是否��Z��互模�?
有时需要知道脚本运行是交互模式�Q�终端模式）�q�是非交互模式（cron或at�Q?。脚本也�?d��ng)R��要这个信息以军_��从哪里取得输入以及输出到哪里�Q��用test命��o�q�带�?t选项很容易确认这一炏V��如果test�q�回��gؓ1�Q�则��Z��互模式�?

Shell代码

/home/l/g/tomotoboy >cat ifinteractive

#!/bin/sh

#ifinteractive

if [ -t ];then

echo "We are interactive with a terminal"

else

echo "We must be running from some background process probably cron or at"

fi

/home/l/g/tomotoboy >ifinteractive

We are interactive with a terminal

/home/l/g/tomotoboy >cat ifinteractive #!/bin/sh #ifinteractive if [ -t ];then echo "We are interactive with a terminal" else echo "We must be running from some background process probably cron or at" fi /home/l/g/tomotoboy >ifinteractive We are interactive with a terminal

��单的if else语句
下一个if语句有可能是使用最�q�泛的：

Shell代码

if条�g

then

命��o1

else

命��o2

fi

if条�g then 命��o1 else 命��o2 fi
使用if语句的else部分可在条�g��试为假旉��取适当动作�?
变量讄��试�Q�下面的例子��试环境变量EDITOR是否已设�|�。如果EDITOR变量为空�Q�将此信息通知用户。如果已讄��Q�在屏幕上显�C�编辑类型�?

Shell代码

/home/l/g/tomotoboy >echo $EDITOR



/home/l/g/tomotoboy >cat ifeditor

#!/bin/sh

#ifeditor

if [ -z "$EDITOR" ];then

#the variable has not been set

echo "Your EDITOR environment is not set"

else

#let's  us see what is it

echo "Using $EDITOR as the default editor"

fi

/home/l/g/tomotoboy >ifeditor

Your EDITOR environment is not set

/home/l/g/tomotoboy >

/home/l/g/tomotoboy >echo $EDITOR /home/l/g/tomotoboy >cat ifeditor #!/bin/sh #ifeditor if [ -z "$EDITOR" ];then #the variable has not been set echo "Your EDITOR environment is not set" else #let's us see what is it echo "Using $EDITOR as the default editor" fi /home/l/g/tomotoboy >ifeditor Your EDITOR environment is not set /home/l/g/tomotoboy >

��最后命令状�?/strong>
前面��目录名传入脚本创徏了一个目录，脚本然后提示用户是否应创建目录。下面的例子创徏一个目录，�q�从当前目录��所�?*.txt文�g拷入新目录。但是这�D�脚本中用最后状态命令检��了每一个脚本是否成功执行。如果命令失败则通知用户�?

Shell代码

/home/l/g/tomotoboy >cat ifmkdir

#!/bin/sh

#ifmkdir

DIR_NAME=testdirec

#where we are?

THERE=`pwd`

#send all output to system dustbin

mkdir $DIR_NAME >/dev/null 2>&1

#is it a directory?

if [ -d $DIR_NAME ];then

#can we cd to the directory

  cd $DIR_NAME

  if [ $? = 0 ];then

  #yes we can

  HERE=`pwd`

  echo "$HERE"

  cp $THERE/*.txt $HERE

  else

   echo "Cannot cd to $DIR_NAME" >&2

   exit 1

  fi

else

  echo "Cannot create directory $DIR_NAME" >&2

  exit 1

fi

/home/l/g/tomotoboy >cat ifmkdir #!/bin/sh #ifmkdir DIR_NAME=testdirec #where we are? THERE=`pwd` #send all output to system dustbin mkdir $DIR_NAME >/dev/null 2>&1 #is it a directory? if [ -d $DIR_NAME ];then #can we cd to the directory cd $DIR_NAME if [ $? = 0 ];then #yes we can HERE=`pwd` echo "$HERE" cp $THERE/*.txt $HERE else echo "Cannot cd to $DIR_NAME" >&2 exit 1 fi else echo "Cannot create directory $DIR_NAME" >&2 exit 1 fi

��单的安全��d��脚本
以下是用��L(f��ng)��录时启动应用前加入相应安全限制功能的基本框架。首先提�C��入用户名和密码，如果用户名和密码均匹配脚本中相应字符�Ԍ��用户��d��成功�Q�否则用户退出。脚本首先设�|�变量�ؓ假—��L��假定用户输入错误�Q�stty当前讄��被保存，以便隐藏passwd域中字符�Q�然后重��C��存stty讄��。如果用户I D和密码正��（密码是myday�Q?�Q�明亮INVALID_USER和INVALID_PASSWD讄��为no表示有效用户或密码，然后执行��试�Q�如果两个变量其中之一为yes�Q�缺省情况下�Q�脚本退出用戗��键入有效的ID和密码，用户��允许进入。这是一�U�登录脚本的基本框架。下面的例子中有效用户ID为dave或tomotoboy�?

Shell代码

#!/bin/sh

#ifpass

#set the variables to false

INVALID_USER=yes

INVALID_PASSWD=yes

#set the current stty settings

SAVEDSTTY=`stty -g`

echo "You are logging into a sensitive area"

echo -n "Enter your ID name:"

read NAME

#hide the characters typed in

stty -echo

echo "Enter your password :"

read PASSWORD

#back on again

stty $SAVEDSTTY

if [ "$NAME" = "tomotoboy" ] || [ "$NAME" = "dave" ]; then

#if a valid then set variable

    INVALID_USER=no

fi

if [ "$PASSWORD" = "myday" ];then

#if valid password then set variable

    INVALID_PASSWD=no

fi

if [ "$INVALID_USER" = "yes" ] || [ "$INVALID_PASSWD" = "yes" ];then

   echo "`basename $0` : Sorry wrong password or userid"

   exit 1

fi

echo "corrent user id and password given"

#!/bin/sh #ifpass #set the variables to false INVALID_USER=yes INVALID_PASSWD=yes #set the current stty settings SAVEDSTTY=`stty -g` echo "You are logging into a sensitive area" echo -n "Enter your ID name:" read NAME #hide the characters typed in stty -echo echo "Enter your password :" read PASSWORD #back on again stty $SAVEDSTTY if [ "$NAME" = "tomotoboy" ] || [ "$NAME" = "dave" ]; then #if a valid then set variable INVALID_USER=no fi if [ "$PASSWORD" = "myday" ];then #if valid password then set variable INVALID_PASSWD=no fi if [ "$INVALID_USER" = "yes" ] || [ "$INVALID_PASSWD" = "yes" ];then echo "`basename $0` : Sorry wrong password or userid" exit 1 fi echo "corrent user id and password given"

Gavin.lee 2009-11-29 12:05 发表评论

控制��结构——case

Gavin.lee — Sun, 29 Nov 2009 04:05:00 GMT

case语句
case语句为多选择语句。可以用case语句匚w��一个��g��一个模式，如果匚w��成功�Q�执行相匚w��的命令。case语句格式如下�Q?

Shell代码

case �?nbsp;in

模式1 )

  命��o1

  . . .

  ;;

模式2 )

  命��o2

  . . .

  ;;

esac

case �?in 模式1 ) 命��o1 . . . ;; 模式2 ) 命��o2 . . . ;; esac

case工作方式如上所�C�。取值后面必��Mؓ单词 in�Q�每一模式必须以右括号�l�束。取值可以�ؓ变量或常数。匹配发现取值符合某一模式后，光��所有命令开始执行直�?;

取值将��匹配的每一个模式。一旦模式匹配，则执行完匚w��模式相应命��o后不再��l�其他模式。如果无一匚w��模式�Q��用星�?捕获该��|��再接受其他输入。模式部分可能包括元字符�Q�与在命令行文�g扩展名例子中使用�q�的匚w��模式�c�d��相同�Q�即�Q?

* ��L��字符�?/td>

�Q?/td> ��L��单字�W��?/td>

[..] �c�L��范围中�Q意字�W��?/td>

来看一个简单的case语句�Q?/strong>

Shell代码

/home/l/g/tomotoboy >cat caseselect

#!/bin/sh

#caseselect

echo - n "Enter a number from 1 to 5 :"

read ANS

case $ANS in

1) echo "you select 1"

;;

2) echo "you select 2"

;;

3) echo "you select 3"

;;

4) echo "you select 4"

;;

5) echo "you select 5"

;;

*) echo "`basename $0`: This is not between 1 and 5" >&2

;;

esac



/home/l/g/tomotoboy >caseselect

- n Enter a number from 1 to 5 :

4

you select 4

/home/l/g/tomotoboy >caseselect

- n Enter a number from 1 to 5 :

7

caseselect: This is not between 1 and 5

/home/l/g/tomotoboy >cat caseselect #!/bin/sh #caseselect echo - n "Enter a number from 1 to 5 :" read ANS case $ANS in 1) echo "you select 1" ;; 2) echo "you select 2" ;; 3) echo "you select 3" ;; 4) echo "you select 4" ;; 5) echo "you select 5" ;; *) echo "`basename $0`: This is not between 1 and 5" >&2 ;; esac /home/l/g/tomotoboy >caseselect - n Enter a number from 1 to 5 : 4 you select 4 /home/l/g/tomotoboy >caseselect - n Enter a number from 1 to 5 : 7 caseselect: This is not between 1 and 5

对匹配模式��用|

Shell代码

/home/l/g/tomotoboy >cat caseterm

#!/bin/sh

#caseterm

echo "choices are.. vt100, vt102, vt220"

echo -n "enter your terminal type :"

read TERMINAL

case $TERMINAL in

vt100|vt102) TERM=vt100

;;

vt220) TERM=vt220

;;

*) echo "`basename $0`: Unknown reponse" >&2

   echo "setting it to vt100 anyway,so there"

   TERM=vt100

;;

esac

export TERM

echo "Your terminal is set to $TERM'

"caseterm" 17 lines, 348 characters



/home/l/g/tomotoboy >caseterm

choices are.. vt100, vt102, vt220

-n enter your terminal type :

vt100

Your terminal is set to vt100'

/home/l/g/tomotoboy >cat caseterm #!/bin/sh #caseterm echo "choices are.. vt100, vt102, vt220" echo -n "enter your terminal type :" read TERMINAL case $TERMINAL in vt100|vt102) TERM=vt100 ;; vt220) TERM=vt220 ;; *) echo "`basename $0`: Unknown reponse" >&2 echo "setting it to vt100 anyway,so there" TERM=vt100 ;; esac export TERM echo "Your terminal is set to $TERM' "caseterm" 17 lines, 348 characters /home/l/g/tomotoboy >caseterm choices are.. vt100, vt102, vt220 -n enter your terminal type : vt100 Your terminal is set to vt100'

提示键入y或n
case的一个有效用法是提示用户响应以决定是否��l�进�E�。这里提�C��入y以��l�处理n退出。如果用戯��入Y、y或yes�Q�处理��l�执行case语句后面部分。如果用戯��入N、n或no或其他响应，用户退��本�?

Shell代码

/home/l/g/tomotoboy >cat caseans

#!/bin/sh

#caseans

echo -n "Do you wish to proceed [y..n]"

read ANS

case $ANS in

y|Y|yes|Yes) echo "yes is selected"

;;

n|N|no|No) echo "no is selectd"

;;

*) echo "`basename $0` : Unknown response" >&2

;;

esac



/home/l/g/tomotoboy >caseans

-n Do you wish to proceed [y..n]

y

yes is selected

/home/l/g/tomotoboy >cat caseans #!/bin/sh #caseans echo -n "Do you wish to proceed [y..n]" read ANS case $ANS in y|Y|yes|Yes) echo "yes is selected" ;; n|N|no|No) echo "no is selectd" ;; *) echo "`basename $0` : Unknown response" >&2 ;; esac /home/l/g/tomotoboy >caseans -n Do you wish to proceed [y..n] y yes is selected

case与命令参��C��?/strong>

Shell代码

/home/l/g/tomotoboy >cat >> caseparam

#!/bin/sh

#caseparam

if [ $# != 1 ];then

   echo "Usage:`basename $0` [start|stop|help]" >&2

fi

OPT=$1

case $OPT in

start) echo "starting..`basename $0`"

;;

stop) echo "stopping..`basename $0`"

;;

help) echo "stopping..`basename $0`"

echo "Usage:`basename $0` [start|stop|help]"

;;

*) echo "stopping..`basename $0`"

echo "Usage:`basename $0` [start|stop|help]"

;;

esac

/home/l/g/tomotoboy >chmod u+x caseparam

/home/l/g/tomotoboy >caseparam help

stopping..caseparam

Usage:caseparam [start|stop|help]

/home/l/g/tomotoboy >caseparam start

starting..caseparam

/home/l/g/tomotoboy >cat >> caseparam #!/bin/sh #caseparam if [ $# != 1 ];then echo "Usage:`basename $0` [start|stop|help]" >&2 fi OPT=$1 case $OPT in start) echo "starting..`basename $0`" ;; stop) echo "stopping..`basename $0`" ;; help) echo "stopping..`basename $0`" echo "Usage:`basename $0` [start|stop|help]" ;; *) echo "stopping..`basename $0`" echo "Usage:`basename $0` [start|stop|help]" ;; esac /home/l/g/tomotoboy >chmod u+x caseparam /home/l/g/tomotoboy >caseparam help stopping..caseparam Usage:caseparam [start|stop|help] /home/l/g/tomotoboy >caseparam start starting..caseparam

捕获输入�q�执行空命��o
不一定要在匹配模式后加入命��o�Q�如果你原本不想做什么，只是在进一步处理前�q��o出意外响应，�q�样做是一�U�好办法。如果要�q�行对应于一个会计部门的帐目报表�Q�必��首先在军_��q�行报表的类型前��认用户输入一个有效的部门��P��匚w��所有可能��|��其他值无效。用case可以很容易实��C��q�功能。下面的脚本中如果用戯��入部门号不是234�?53�?55�?54�Q�用户退出�ƈ�q�回可用信息。一旦响应了用户的有效部门号�Q�脚本应用同��L(f��ng)��技术取得报表类型，在case语句末尾昄��有效的部门号和报表类型。脚本如下：

Shell代码

#!/bin/sh

# casevalid

echo -n "enter the account dept No: "

read ACC

case $ACC in

      234);;

      453);;

      655);;

      454);;

         *) echo "basename $01`: Unknon dept No"

              echo "try..234,453,655,454"

              exit 1

              ;;

esac

#if we are here, then we have a validdated the dept no

echo " 1 . post"

echo " 2 . prior"

echo -n "enter the type of report: "

read ACC_TYPE

   case $ACC_TYPE in

   1)TYPE=post;;

   2)TYPE=prior;;

   *) echo "`basename $0`: Unknown account type." >&2

"casevalid" 29 lines, 665 characters

/home/l/g/tomotoboy >casevalid

-n enter the account dept No:

454

1 . post

2 . prior

-n enter the type of report:

1

now running report for dept 454 for the type post

Gavin.lee 2009-11-29 12:05 发表评论

条�g控制�Q�test�Q�expr……）

Gavin.lee — Sun, 29 Nov 2009 04:01:00 GMT

��试文�g状�?/strong>
test
test一般有两种格式�Q�即�Q?
test condition
�?
[ condition ]
使用�Ҏ(gu��)��h��Q�要注意在条件两边加上空根{��测试文件状态的条�g表达式很多，但是最常用的可在下表中查到�?

-d 目录 -s 文�g长度大于0、非�I?/td>

-f 正规文�g -w 可写

-L �W�号�q�接 -u 文�g有suid位设�|?/td>

-r 可读 -x 可执�?/td>

Shell代码

/home/l/g/tomotoboy >test -d sed.out
/home/l/g/tomotoboy >echo $?
1

/home/l/g/tomotoboy >test -f sed.out
/home/l/g/tomotoboy >echo $?
0

/home/l/g/tomotoboy >[ -f sed.out ]
/home/l/g/tomotoboy >echo $?
0
/home/l/g/tomotoboy >[ -d sed.out ]
/home/l/g/tomotoboy >echo $?
1

/home/l/g/tomotoboy >[ -x sed.out ]
/home/l/g/tomotoboy >echo $?
1

/home/l/g/tomotoboy >[ -r sed.out ]
/home/l/g/tomotoboy >echo $?
0

/home/l/g/tomotoboy >[ -w sed.out ]
/home/l/g/tomotoboy >echo $?
0

/home/l/g/tomotoboy >test -d sed.out /home/l/g/tomotoboy >echo $? 1 /home/l/g/tomotoboy >test -f sed.out /home/l/g/tomotoboy >echo $? 0 /home/l/g/tomotoboy >[ -f sed.out ] /home/l/g/tomotoboy >echo $? 0 /home/l/g/tomotoboy >[ -d sed.out ] /home/l/g/tomotoboy >echo $? 1 /home/l/g/tomotoboy >[ -x sed.out ] /home/l/g/tomotoboy >echo $? 1 /home/l/g/tomotoboy >[ -r sed.out ] /home/l/g/tomotoboy >echo $? 0 /home/l/g/tomotoboy >[ -w sed.out ] /home/l/g/tomotoboy >echo $? 0

��试时��用逻辑操作�W?/strong>
��试文�g状态是否�ؓOK�Q�但是有时要比较两个文�g状态。shell提供三种逻辑操作完成此功能�?
-a   逻辑与，操作�W�两边均为真�Q�结果�ؓ真，否则为假�?
-o   逻辑或，操作�W�两边一边�ؓ真，�l�果为真�Q�否则�ؓ假�?
! 逻辑否，条�g为假�Q�结果�ؓ真�?
下面比较两个文�gsed.out、sed.txt�Q?

Shell代码

/home/l/g/tomotoboy >ls -al sed.out sed.txt
-rw-r--r--   1 tomotoboy member       159 Jul 30 16:47 sed.out
-rw-r--r--   1 tomotoboy member       655 Jul 31 14:44 sed.txt
/home/l/g/tomotoboy >[ -w sed.out -a -w sed.txt ]
/home/l/g/tomotoboy >echo $?
0

/home/l/g/tomotoboy >[ -x sed.out -a -r sed.txt]
-bash: [: missing `]'
/home/l/g/tomotoboy >[ -x sed.out -a -r sed.txt ]
/home/l/g/tomotoboy >echo $?
1

/home/l/g/tomotoboy >[ -x sed.out -o -r sed.txt ]
/home/l/g/tomotoboy >echo $?
0

/home/l/g/tomotoboy >ls -al sed.out sed.txt -rw-r--r-- 1 tomotoboy member 159 Jul 30 16:47 sed.out -rw-r--r-- 1 tomotoboy member 655 Jul 31 14:44 sed.txt /home/l/g/tomotoboy >[ -w sed.out -a -w sed.txt ] /home/l/g/tomotoboy >echo $? 0 /home/l/g/tomotoboy >[ -x sed.out -a -r sed.txt] -bash: [: missing `]' /home/l/g/tomotoboy >[ -x sed.out -a -r sed.txt ] /home/l/g/tomotoboy >echo $? 1 /home/l/g/tomotoboy >[ -x sed.out -o -r sed.txt ] /home/l/g/tomotoboy >echo $? 0

字符串测�?/strong>
字符串测试是错误捕获很重要的一部分�Q�特别在��试用户输入或比较变量时��ؓ重要。字�W�串��试�?�U�格式：
test "string"
test string_operator "string"
test "string" string_operator "string"
[ string_operator "string" ]
[ "string" string_operator "string" ]
�q�里�Q�string_operator可�ؓ�Q?

=     两个字符串相�{��?/td>

!=    两个字符串不�{��?/td>

-z    �I�Z��?/td>

-n    非空丌Ӏ?/td>

Shell代码

/home/l/g/tomotoboy >[ -z $HELLO ]
/home/l/g/tomotoboy >echo $?
0

/home/l/g/tomotoboy >HELLO="hello"
/home/l/g/tomotoboy >[ -z $HELLO ]
/home/l/g/tomotoboy >echo $?
1

/home/l/g/tomotoboy >[ -n $HELLO ]
/home/l/g/tomotoboy >echo $?
0

/home/l/g/tomotoboy >[ !-n $HELLO ]
[ nohup -p 1 $HELLO ]
-bash: [: too many arguments
/home/l/g/tomotoboy >[ ![ -n $HELLO ] ]
[ [ -z $HELLO ] -n $HELLO ] ]
-bash: [: too many arguments
/home/l/g/tomotoboy >HI="hi"
/home/l/g/tomotoboy >[ $HELLO = $HI]
-bash: [: missing `]'
/home/l/g/tomotoboy >[ $HELLO = $HI ]
/home/l/g/tomotoboy >echo $?
1

/home/l/g/tomotoboy >[ $HELLO != $HI ]
/home/l/g/tomotoboy >echo $?
0

/home/l/g/tomotoboy >[ -z $HELLO ] /home/l/g/tomotoboy >echo $? 0 /home/l/g/tomotoboy >HELLO="hello" /home/l/g/tomotoboy >[ -z $HELLO ] /home/l/g/tomotoboy >echo $? 1 /home/l/g/tomotoboy >[ -n $HELLO ] /home/l/g/tomotoboy >echo $? 0 /home/l/g/tomotoboy >[ !-n $HELLO ] [ nohup -p 1 $HELLO ] -bash: [: too many arguments /home/l/g/tomotoboy >[ ![ -n $HELLO ] ] [ [ -z $HELLO ] -n $HELLO ] ] -bash: [: too many arguments /home/l/g/tomotoboy >HI="hi" /home/l/g/tomotoboy >[ $HELLO = $HI] -bash: [: missing `]' /home/l/g/tomotoboy >[ $HELLO = $HI ] /home/l/g/tomotoboy >echo $? 1 /home/l/g/tomotoboy >[ $HELLO != $HI ] /home/l/g/tomotoboy >echo $? 0

��试数�?/strong>
��试数值可以��用许多操作符�Q�一般格式如下：
"number" numeric_operator "number"
或�?
[ "number" numeric_operator "number" ]
numeric_operator可�ؓ�Q?

-eq   数值相�{��?/td>

-ne   数��g��相等�?/td>

-gt   �W�一个数大于�W�二个数�?/td>

-lt   �W�一个数��于�W�二个数�?/td>

-le   �W�一个数��于�{�于�W�二个数�?/td>

-ge   �W�一个数大于�{�于�W�二个数�?/td>

Shell代码

/home/l/g/tomotoboy >Nbr=10
/home/l/g/tomotoboy >Nbr1=20
/home/l/g/tomotoboy >echo $?
0

/home/l/g/tomotoboy >Nbr -ne Nbr1
-bash: Nbr: command not found
/home/l/g/tomotoboy >$Nbr -ne $Nbr1
-bash: 10: command not found
/home/l/g/tomotoboy >[ "$Nbr" -ne "$Nbr1" ]
/home/l/g/tomotoboy >echo $?
0

/home/l/g/tomotoboy >[ "$Nbr" -e "$Nbr1" ]
-bash: [: -e: binary operator expected
/home/l/g/tomotoboy >[ "$Nbr" -eq "$Nbr1" ]
/home/l/g/tomotoboy >echo $?
1
/home/l/g/tomotoboy >[ "$Nbr" -gt "$Nbr1" ]
/home/l/g/tomotoboy >echo 4?
4?
/home/l/g/tomotoboy >echo $?
0

/home/l/g/tomotoboy >[ "$Nbr" -gt "$Nbr1" ]
/home/l/g/tomotoboy >echo $?
1

/home/l/g/tomotoboy >[ "$Nbr" -lt "$Nbr1" ]
/home/l/g/tomotoboy >echo $?
0

/home/l/g/tomotoboy >Nbr=10 /home/l/g/tomotoboy >Nbr1=20 /home/l/g/tomotoboy >echo $? 0 /home/l/g/tomotoboy >Nbr -ne Nbr1 -bash: Nbr: command not found /home/l/g/tomotoboy >$Nbr -ne $Nbr1 -bash: 10: command not found /home/l/g/tomotoboy >[ "$Nbr" -ne "$Nbr1" ] /home/l/g/tomotoboy >echo $? 0 /home/l/g/tomotoboy >[ "$Nbr" -e "$Nbr1" ] -bash: [: -e: binary operator expected /home/l/g/tomotoboy >[ "$Nbr" -eq "$Nbr1" ] /home/l/g/tomotoboy >echo $? 1 /home/l/g/tomotoboy >[ "$Nbr" -gt "$Nbr1" ] /home/l/g/tomotoboy >echo 4? 4? /home/l/g/tomotoboy >echo $? 0 /home/l/g/tomotoboy >[ "$Nbr" -gt "$Nbr1" ] /home/l/g/tomotoboy >echo $? 1 /home/l/g/tomotoboy >[ "$Nbr" -lt "$Nbr1" ] /home/l/g/tomotoboy >echo $? 0

可以不必��整数值放入变量，直接用数字比较即可，但要加引受��?

Shell代码

/home/l/g/tomotoboy >[ "99" -ge "60" ]
/home/l/g/tomotoboy >echo $?
0

/home/l/g/tomotoboy >[ "99" -ge "60" ] /home/l/g/tomotoboy >echo $? 0

expr用法
expr命��o一般用于整数��|��但也可用于字�W�串。一般格式�ؓ�Q?
expr argument operator argument
expr也是一个手工命令行计数器�?

Shell代码

/home/l/g/tomotoboy >expr 10 + 10
20

/home/l/g/tomotoboy >expr 45 / 4
11

/home/l/g/tomotoboy >expr 10 + 10 20 /home/l/g/tomotoboy >expr 45 / 4 11

使用乘号�Ӟ��必须用反斜线屏蔽其特定含义。因为shell可能会误解显�C�星��L(f��ng)��意义

Shell代码

/home/l/g/tomotoboy >expr 30 \* 100
3000

/home/l/g/tomotoboy >expr 30 \* 100 3000

增量计数expr在��@环中用于增量计算。首先，循环初始化�ؓ 0�Q�然后��@环值加1�Q�反引号的用法意��x��代命令。最基本的一�U�是从（expr�Q�命令接受输出�ƈ��之攑օ�循环变量

Shell代码

/home/l/g/tomotoboy >loop=0
/home/l/g/tomotoboy >loop=`expr $loop + 1`
/home/l/g/tomotoboy >echo

/home/l/g/tomotoboy >echo $?
0
/home/l/g/tomotoboy >echo $loop
1

/home/l/g/tomotoboy >loop=0 /home/l/g/tomotoboy >loop=`expr $loop + 1` /home/l/g/tomotoboy >echo /home/l/g/tomotoboy >echo $? 0 /home/l/g/tomotoboy >echo $loop 1
数值测�?/strong>
可以用expr��试一个数。如果试图计��非整数�Q�将�q�回错误�?
/

Shell代码

home/l/g/tomotoboy >f=1.1
/home/l/g/tomotoboy >expr f + 10
expr: non-numeric argument
/home/l/g/tomotoboy >echo $?
2

/home/l/g/tomotoboy >expr $HELLO + 10
expr: non-numeric argument
/home/l/g/tomotoboy >echo $?
2

/home/l/g/tomotoboy >expr "$HELLO"  + 10
expr: non-numeric argument
/home/l/g/tomotoboy >echo $?
2

/home/l/g/tomotoboy >expr $f + 10
expr: non-numeric argument

home/l/g/tomotoboy >f=1.1 /home/l/g/tomotoboy >expr f + 10 expr: non-numeric argument /home/l/g/tomotoboy >echo $? 2 /home/l/g/tomotoboy >expr $HELLO + 10 expr: non-numeric argument /home/l/g/tomotoboy >echo $? 2 /home/l/g/tomotoboy >expr "$HELLO" + 10 expr: non-numeric argument /home/l/g/tomotoboy >echo $? 2 /home/l/g/tomotoboy >expr $f + 10 expr: non-numeric argument

expr也可以返回其本��n的退出状态，不幸的是�q�回��g��pȝ��最后退出命令刚好相反，成功�q�回1�Q��Q何其他��gؓ无效或错误。下面的例子��试两个字符串是否相�{�，�q�里字符串�ؓ“hello”�?#8220;hello” �?

Shell代码

/home/l/g/tomotoboy >expr $HELLO = "hello"
1
/home/l/g/tomotoboy >echo $?
0

/home/l/g/tomotoboy >expr $HELLO = "hello" 1 /home/l/g/tomotoboy >echo $? 0

模式匚w��
expr也有模式匚w��功能。可以��用expr通过指定冒号选项计算字符串中字符数�?*意即��M��字符重复0�ơ或多次.

Shell代码

/home/l/g/tomotoboy >cat sed.txt
605408211   pts/16       Jul 31 13:54   (218.0.1.42)
caodejun   pts/44       Jul 31 14:16    (219.148.133.31)
duke1988   pts/45       Jul 31 14:41    (218.104.163.66)
liuzk423   pts/6        Jul 20 08:27    (219.245.104.240)
nefu_luyanshen   pts/23       Jul 31 14:33      (218.25.6.142)
nefu_luyanshen   pts/48       Jul 31 12:59      (218.25.6.142)
shuzigui   pts/21       Jul 31 12:11    (121.35.248.193)
tomotoboy   pts/41       Jul 31 13:31   (219.221.99.155)
waterlooz   pts/25       Jul 31 08:48   (121.0.29.225)
wsoangel   pts/35       Jul 31 13:40    (116.233.219.10)
xp55699312   pts/42       Jul 31 14:12  (61.152.132.103)
zyy0904    pts/43       Jul 31 13:53    (125.33.195.36)

/home/l/g/tomotoboy >VALUE=sed.txt
/home/l/g/tomotoboy >expr $VALUE : tomotoboy , '.*'
expr: syntax error
/home/l/g/tomotoboy >expr $VALUE : tomotoboy
0

/home/l/g/tomotoboy >
/home/l/g/tomotoboy >expr $VALUE:tomotoboy
sed.txt:tomotoboy
/home/l/g/tomotoboy >expr $VALUE: tomotoboy
expr: syntax error
/home/l/g/tomotoboy >expr $VALUE : tomotoboy
0
/home/l/g/tomotoboy >expr $VALUE :tomotoboy
expr: syntax error
/home/l/g/tomotoboy >expr $VALUE : tomotoboy
0
/home/l/g/tomotoboy >expr $VALUE : tomotoboy, '.*'
expr: syntax error
/home/l/g/tomotoboy >expr $VALUE : tomotoboy , '.*'
expr: syntax error

/home/l/g/tomotoboy >expr $VALUE :  '.*'
7

/home/l/g/tomotoboy >expr $VALUE : tomotoboy
0

/home/l/g/tomotoboy >expr $VALUE : "tomotoboy"
0

/home/l/g/tomotoboy >expr $VALUE : "nefu_luyanshen"
0

/home/l/g/tomotoboy >cat sed.txt 605408211 pts/16 Jul 31 13:54 (218.0.1.42) caodejun pts/44 Jul 31 14:16 (219.148.133.31) duke1988 pts/45 Jul 31 14:41 (218.104.163.66) liuzk423 pts/6 Jul 20 08:27 (219.245.104.240) nefu_luyanshen pts/23 Jul 31 14:33 (218.25.6.142) nefu_luyanshen pts/48 Jul 31 12:59 (218.25.6.142) shuzigui pts/21 Jul 31 12:11 (121.35.248.193) tomotoboy pts/41 Jul 31 13:31 (219.221.99.155) waterlooz pts/25 Jul 31 08:48 (121.0.29.225) wsoangel pts/35 Jul 31 13:40 (116.233.219.10) xp55699312 pts/42 Jul 31 14:12 (61.152.132.103) zyy0904 pts/43 Jul 31 13:53 (125.33.195.36) /home/l/g/tomotoboy >VALUE=sed.txt /home/l/g/tomotoboy >expr $VALUE : tomotoboy , '.*' expr: syntax error /home/l/g/tomotoboy >expr $VALUE : tomotoboy 0 /home/l/g/tomotoboy > /home/l/g/tomotoboy >expr $VALUE:tomotoboy sed.txt:tomotoboy /home/l/g/tomotoboy >expr $VALUE: tomotoboy expr: syntax error /home/l/g/tomotoboy >expr $VALUE : tomotoboy 0 /home/l/g/tomotoboy >expr $VALUE :tomotoboy expr: syntax error /home/l/g/tomotoboy >expr $VALUE : tomotoboy 0 /home/l/g/tomotoboy >expr $VALUE : tomotoboy, '.*' expr: syntax error /home/l/g/tomotoboy >expr $VALUE : tomotoboy , '.*' expr: syntax error /home/l/g/tomotoboy >expr $VALUE : '.*' 7 /home/l/g/tomotoboy >expr $VALUE : tomotoboy 0 /home/l/g/tomotoboy >expr $VALUE : "tomotoboy" 0 /home/l/g/tomotoboy >expr $VALUE : "nefu_luyanshen" 0
�q�里没有搞懂�Q�tomotoboy和nefu_luyanshen�Q�明明存在而结果是0

Gavin.lee 2009-11-29 12:01 发表评论

Gavin.lee — Sun, 29 Nov 2009 04:00:00 GMT

本地变量
昄��变量

Shell代码

$GREAT_PICTURE ="die hard"

$echo ${GREAT_PICTURE}

die hard



$DOLLAR=99

$echo ${DOLLAR}

99



$LAST_FILE=ZLPSO.txt

$echo ${LAST_FILE}

ZLPSO.txt

$GREAT_PICTURE ="die hard" $echo ${GREAT_PICTURE} die hard $DOLLAR=99 $echo ${DOLLAR} 99 $LAST_FILE=ZLPSO.txt $echo ${LAST_FILE} ZLPSO.txt

清除变量

Shell代码

unset variable-name

$PC=enterprise

$echo ${PC}

enterprise

$unset PC

$echp ${PC}

$

unset variable-name $PC=enterprise $echo ${PC} enterprise $unset PC $echp ${PC} $

昄��所有本地shell变量
使用set命��o昄��所有本地定义的shell变量

Shell代码

$set

$set

�l�合变量�?
��变量�ƈ排可以��变量�l�合在一�?

Shell代码

echo ${variable-name}${variable-name}



$FIRST="Bruce"

$SURNAME=Willis

$echo ${FIRST}${SURNAME}

Bruce Willis

echo ${variable-name}${variable-name} $FIRST="Bruce" $SURNAME=Willis $echo ${FIRST}${SURNAME} Bruce Willis

��试变量是否已经讄��
有时要测试是否已讄��或初始化变量。如果未讄��或初始化�Q�就可以使用另一倹{��此�?
令格式�ؓ�Q?
${variable:-value}

环境变量

嵌入shell变量
Brourne shell有一些预留的环境变量名，�q�些变量名不能用作其他用途。通常�?etc/profile中徏立这些嵌入的环境变量�Q�但也不完全是，�q�取决于用户自己。以下是嵌入 shell变量列表�?

讄��环境变量
VARIABLE-NAME= value�Q�export VARIABLE-NAME
在两个命令之间是一个分��P��也可以这样写�Q?
VARIABLE-NAME= value
Export VARIABLE-NAME

昄��和清除环境变量与本地变量一�?

set命��o
�?HOME.profile文�g中设�|�环境变量时�Q�还有另一�U�方法导��些变量。��用set命��o- a选项�Q�即set -a指明所有变量直接被导出。不要在/etc/profile中��用这�U�方法，最好只在自��q��$HOME.profile文�g中��?

Shell代码

$pg .profile

# .profile

MAIL=/usr/mail/${LOGNAME:?}

PS1="`hostname`>"

$pg .profile # .profile MAIL=/usr/mail/${LOGNAME:?} PS1="`hostname`>"

位置变量参数
在脚本中位置参数

$0 $1 &2 $3 $4 $5 $6 $6 $7 $8 $9 ${10} ${11} ……

脚本文�g�? �W�一个参�? �W�二个参�? ……

特定变量函数

$# 传递到脚本的参��C��?/td>

$* 以一个单字符串显�C�所有向脚本传递的参数。与位置变量不同�Q�此选项参数可超�q?9�?/td>

$$ 脚本�q�行的当前进�E�ID�?/td>

$! 后台�q�行的最后一个进�E�的�q�程ID�?/td>

$@ �?#相同�Q�但是��用时加引��P��q�在引号中返回每个参�?/td>

$- 昄��shell使用的当前选项�Q�与set命��o功能相同

$? 昄��最后命令的退出状态�?表示没有错误�Q�其他�Q何��D��明有错误�?/td>

Gavin.lee 2009-11-29 12:00 发表评论

登陆环境

Gavin.lee — Sun, 29 Nov 2009 03:59:00 GMT
首先看看/etc/passwd
它保存着用户名、加密后的密码等信息�Q�我们登录系�l�所有信息都要在里面查找

Shell代码

-bash-3.00$ cat /etc/passwd | tr ":" "\t" | sort -k0
adm     x       4       4       Admin   /var/adm
bin     x       2       2               /usr/bin
daemon  x       1       1               /
gdm     x       50      50      GDM Reserved UID        /
jiang   x       100     1               /       /bin/sh
listen  x       37      4       Network Admin   /usr/net/nls
lp      x       71      8       Line Printer Admin      /usr/spool/lp
noaccess        x       60002   60002   No Access User  /
nobody  x       60001   60001   NFS Anonymous Access User       /
nobody4 x       65534   65534   SunOS 4.x NFS Anonymous Access User     /
nuucp   x       9       9       uucp Admin      /var/spool/uucppublic

/usr/lib/uucp/uucico
root    x       0       0       Super-User      /       /bin/bash
smmsp   x       25      25      SendMail Message Submission Program     /
sys     x       3       3               /
ttaserv x       101     100             /       /bin/sh
ttasys  x       102     100             /       /bin/sh
uucp    x       5       5       uucp Admin      /usr/lib/uucp
webservd        x       80      80      WebServer Reserved UID  /
www     x       81      81      WebServer User  /
-bash-3.00$ cat /etc/passwd | sed -n  '/jiang/'p
jiang:x:100:1::/:/bin/sh
-bash-3.00$ cat /etc/passwd | sed -n  '/jiang/'p | tr ':' '\t'
jiang   x       100     1               /       /bin/sh

-bash-3.00$ cat /etc/passwd | tr ":" "\t" | sort -k0 adm x 4 4 Admin /var/adm bin x 2 2 /usr/bin daemon x 1 1 / gdm x 50 50 GDM Reserved UID / jiang x 100 1 / /bin/sh listen x 37 4 Network Admin /usr/net/nls lp x 71 8 Line Printer Admin /usr/spool/lp noaccess x 60002 60002 No Access User / nobody x 60001 60001 NFS Anonymous Access User / nobody4 x 65534 65534 SunOS 4.x NFS Anonymous Access User / nuucp x 9 9 uucp Admin /var/spool/uucppublic /usr/lib/uucp/uucico root x 0 0 Super-User / /bin/bash smmsp x 25 25 SendMail Message Submission Program / sys x 3 3 / ttaserv x 101 100 / /bin/sh ttasys x 102 100 / /bin/sh uucp x 5 5 uucp Admin /usr/lib/uucp webservd x 80 80 WebServer Reserved UID / www x 81 81 WebServer User / -bash-3.00$ cat /etc/passwd | sed -n '/jiang/'p jiang:x:100:1::/:/bin/sh -bash-3.00$ cat /etc/passwd | sed -n '/jiang/'p | tr ':' '\t' jiang x 100 1 / /bin/sh

用户��d��时自动读�?etc/profile 此文件包含：

全局或局部环境变量�?
PATH信息
�l�端讄��
安全命��o
日期信息或放弃操作信�?

让我们来看一个详�l�的profile

Shell代码

-bash-3.00$ cat /etc/profile
#ident  "@(#)profile    1.19    01/03/13 SMI"   /* SVr4.0 1.3   */

# The profile that all logins get before using their own .profile.

trap ""  2 3 #忽略两个信号�Q�即使用QUIT退出或键停止文件执�?


ulimit -d 100000 #限制内存溢出�Q�设�|�数据段的最大��|��单位kbytes
export LOGNAME PATH #导出LOGNAME �?nbsp;PATH
export LANG=C #讄��语言环境
if [ "$TERM" = "" ] #讄��l�端�c�d��
then
        if /bin/i386
        then
                TERM=sun-color
        else
                TERM=sun
        fi
        export TERM
fi

#       Login and -su shells get /etc/profile services.
#       -rsh is given its environment in its .profile.

case "$0" in

-sh | -ksh | -jsh | -bash)

        if [ ! -f .hushlogin ]
        then
                /usr/sbin/quota
                #       Allow the user to break the Message-Of-The-Day only.
                trap "trap '' 2"  2
                /bin/cat -s /etc/motd
                trap "" 2

                /bin/mail -E
                case $? in #建立邮�g信息�Q�当有新邮�g到达时显�C�提�C�Z��息）
                0)
                        echo "You have new mail."
                        ;;
                2)
                        echo "You have mail."
                        ;;
                esac
        fi
esac

umask 022 #讄��umask��|��使文件创建时带有一定的�~�省权限位集
trap  2 3 #重新讄��捕捉信号和QUIT�Q�即恢复信号量的默认操作

# add by jianghua

export
PATH=$PATH:/usr/local/bin:/usr/local/mysql/bin:/opt/SunStudio_11/SUNWspro/bin:/usr/ccs/bin:

/usr/sfw/bin:.
export HISTSIZE=1000
export HISTFILESIZE=1000
#
# Show Unix-Center.Net Welcome Message in Chinese
#
show_welcome_message

-bash-3.00$ cat /etc/profile #ident "@(#)profile 1.19 01/03/13 SMI" /* SVr4.0 1.3 */ # The profile that all logins get before using their own .profile. trap "" 2 3 #忽略两个信号�Q�即使用QUIT退出或键停止文件执�? ulimit -d 100000 #限制内存溢出�Q�设�|�数据段的最大��|��单位kbytes export LOGNAME PATH #导出LOGNAME �?PATH export LANG=C #讄��语言环境 if [ "$TERM" = "" ] #讄��l�端�c�d�� then if /bin/i386 then TERM=sun-color else TERM=sun fi export TERM fi # Login and -su shells get /etc/profile services. # -rsh is given its environment in its .profile. case "$0" in -sh | -ksh | -jsh | -bash) if [ ! -f .hushlogin ] then /usr/sbin/quota # Allow the user to break the Message-Of-The-Day only. trap "trap '' 2" 2 /bin/cat -s /etc/motd trap "" 2 /bin/mail -E case $? in #建立邮�g信息�Q�当有新邮�g到达时显�C�提�C�Z��息） 0) echo "You have new mail." ;; 2) echo "You have mail." ;; esac fi esac umask 022 #讄��umask��|��使文件创建时带有一定的�~�省权限位集 trap 2 3 #重新讄��捕捉信号和QUIT�Q�即恢复信号量的默认操作 # add by jianghua export PATH=$PATH:/usr/local/bin:/usr/local/mysql/bin:/opt/SunStudio_11/SUNWspro/bin:/usr/ccs/bin: /usr/sfw/bin:. export HISTSIZE=1000 export HISTFILESIZE=1000 # # Show Unix-Center.Net Welcome Message in Chinese # show_welcome_message

用户�?HOME.profile
下面昄��如何在命令提�C�符中设�|�主机名�Q?

Shell代码

-bash-3.00$ PS1='$PWD >'
/home/l/g/tomotoboy >export PS1

-bash-3.00$ PS1='$PWD >' /home/l/g/tomotoboy >export PS1

stty用于讄��l�端�Ҏ(gu��)��。要查询现在的stty选项�Q��用stty -a

Shell代码

/home/l/g/tomotoboy >stty -a
speed 9600 baud;
rows = 25; columns = 82; ypixels = 0; xpixels = 0;
csdata ?
eucw 1:0:0:0, scrw 1:0:0:0
intr = ^c; quit = ^\; erase = ^?; kill = ^u;
eof = ^d; eol = ; eol2 = ; swtch = ;
start = ^q; stop = ^s; susp = ^z; dsusp = ^y;
rprnt = ^r; flush = ^o; werase = ^w; lnext = ^v;
-parenb -parodd cs8 -cstopb -hupcl cread -clocal -loblk -crtscts -crtsxoff -parext

-ignbrk brkint -ignpar -parmrk -inpck -istrip -inlcr -igncr icrnl -iuclc
ixon -ixany -ixoff imaxbel
isig icanon -xcase echo echoe echok -echonl -noflsh
-tostop echoctl -echoprt echoke -defecho -flusho -pendin iexten
opost -olcuc onlcr -ocrnl -onocr -onlret -ofill -ofdel tab3

/home/l/g/tomotoboy >stty -a speed 9600 baud; rows = 25; columns = 82; ypixels = 0; xpixels = 0; csdata ? eucw 1:0:0:0, scrw 1:0:0:0 intr = ^c; quit = ^\; erase = ^?; kill = ^u; eof = ^d; eol = ; eol2 = ; swtch = ; start = ^q; stop = ^s; susp = ^z; dsusp = ^y; rprnt = ^r; flush = ^o; werase = ^w; lnext = ^v; -parenb -parodd cs8 -cstopb -hupcl cread -clocal -loblk -crtscts -crtsxoff -parext -ignbrk brkint -ignpar -parmrk -inpck -istrip -inlcr -igncr icrnl -iuclc ixon -ixany -ixoff imaxbel isig icanon -xcase echo echoe echok -echonl -noflsh -tostop echoctl -echoprt echoke -defecho -flusho -pendin iexten opost -olcuc onlcr -ocrnl -onocr -onlret -ofill -ofdel tab3

创徏.logout文�g

Shell代码

trap "$HOME /.logout " 0

/home/l/g/tomotoboy >cat .logout
rm -f $HOME/*.txt
rm -f $HOME/*.tmp
rm -f $HOME/x*
echo "Bye...bye $LOGNAME"

Gavin.lee 2009-11-29 11:59 发表评论

Gavin.lee — Sun, 29 Nov 2009 03:57:00 GMT

• 实用的分�c�（sort�Q�操作�?
sort命��o的一般格式�ؓ�Q?
sort -cmu -o output_file [other options] +pos1 +pos2 input_files
下面��要介�l�一下s o r t的参敎ͼ�
-c ��试文�g是否已经分类�?
-m 合�ƈ两个分类文�g�?
-u 删除所有复制行�?
-o 存储s o r t�l�果的输出文件名�?
其他选项有：
-b 使用域进行分�c�L��Q�忽略第一个空根{�?
-n 指定分类是域上的数字分类�?
-t 域分隔符�Q�用非空格或t a b键分隔域�?
-r 对分�c�L��序或比较求逆�?
+n n为域受��用此域号开始分�c�R�?
n n为域受��在分类比较时忽略此域，一般与+ n一起��用�?
post1 传递到m�Q�n。m为域��P��n为开始分�c�d��W�数�Q�例�?�Q?意即以第5域分�c�，从第7
个字�W�开始�?
举例�Q?
按第一个域分类
-bash-3.00$ sort -k0 sed.txt
打印分类后的最后第一�?
-bash-3.00$ sort -k0 sed.txt | tail -1
打印分类后的�W�一�?
-bash-3.00$ sort -k0 sed.txt | head -1
awk使用sort输出�l�果
-bash-3.00$ sort -k0 sed.txt | head -1 | awk '{if($1=="caodejun")print $1}'
��两个分�c�L��件合�q?
-bash-3.00$ sort -m sed.txt sort.txt
��文件合�q�前�Q�它们必��d��被分�c�R��合�q�文件可用于事务处理和�Q何种�cȝ��修改操作�?
下面�q�个例子�Q�因为忘了把两个家电(sh��)名称加入文�g�Q�它们被攑֜�一个单独的文�g里，现在��?
之�ƈ入一个文件。分�cȝ��合�ƈ格式�?#8216;sort -m sorted_file1 sorted_file2’�?

删除重复�?
-bash-3.00$ sort -u sed.txt

• uniq
uniq用来从一个文本文件中去除或禁止重复行。一般uniq假定文�g已分�c�，�q�且�l�果正确。我们�ƈ不强制要求这样做�Q�如果愿意，可以使用��M��非排序文本，甚至是无规律行�?
-bash-3.00$ who | awk '{print $1} ' |uniq
liuzk423
605408211
shuzigui
nefu_luyanshen
waterlooz
wsoangel
tomotoboy
xp55699312
zyy0904
caodejun
duke1988
605408211
nefu_luyanshen
zyy0904
lonelysand

昄��不唯一的行
-bash-3.00$ who | awk '{print $1} ' |uniq -d

-c打印每一重复行出现次数�?
-bash-3.00$ who | awk '{print $1} ' |uniq -c
   1 liuzk423
   1 605408211
   1 shuzigui
   1 nefu_luyanshen
   1 waterlooz
   1 wsoangel
   1 tomotoboy
   1 xp55699312
   1 zyy0904
   1 caodejun
   1 duke1988
   1 605408211
   1 nefu_luyanshen
   1 zyy0904
   1 lonelysand
�q�里没有搞懂nefu_luyanshen明明重复�Q�却昄��重复行数目�ؓ1

对特定域�q�行��试�Q��?n只测试一行一部分的唯一性�?
-bash-3.00$ who | awk '{print $1} ' |uniq -n2
liuzk423

• join
��两个已�l�分好类的文件连接在一起哈。一些系�l�要求��用join时文件域要少�?0�Q��ؓ公��^赯��Q�如果域大于20�Q�应使用DBMS�pȝ��Q�其一般格式如下：
join [options] in_file1 in_file2

-bash-3.00$ cat sed.txt
605408211   pts/16       Jul 31 13:54   (218.0.1.42)
caodejun   pts/44       Jul 31 14:16    (219.148.133.31)
duke1988   pts/45       Jul 31 14:41    (218.104.163.66)
liuzk423   pts/6        Jul 20 08:27    (219.245.104.240)
nefu_luyanshen   pts/23       Jul 31 14:33      (218.25.6.142)
nefu_luyanshen   pts/48       Jul 31 12:59      (218.25.6.142)
shuzigui   pts/21       Jul 31 12:11    (121.35.248.193)
tomotoboy   pts/41       Jul 31 13:31   (219.221.99.155)
waterlooz   pts/25       Jul 31 08:48   (121.0.29.225)
wsoangel   pts/35       Jul 31 13:40    (116.233.219.10)
xp55699312   pts/42       Jul 31 14:12 (61.152.132.103)
zyy0904    pts/43       Jul 31 13:53    (125.33.195.36)
-bash-3.00$ cat sort.txt
605408211   pts/16       Jul 31 13:54   (218.0.1.42)
caodejun   pts/44       Jul 31 14:16    (219.148.133.31)
duke1988   pts/45       Jul 31 14:41    (218.104.163.66)
-bash-3.00$ join sed.txt sort.txt
605408211 pts/16 Jul 31 13:54 (218.0.1.42) pts/16 Jul 31 13:54 (218.0.1.42)
caodejun pts/44 Jul 31 14:16 (219.148.133.31) pts/44 Jul 31 14:16 (219.148.133.31)
duke1988 pts/45 Jul 31 14:41 (218.104.163.66) pts/45 Jul 31 14:41 (218.104.163.66)

选择匚w��
-bash-3.00$ join -a1 -a2 sed.txt sort.txt
605408211 pts/16 Jul 31 13:54 (218.0.1.42) pts/16 Jul 31 13:54 (218.0.1.42)
caodejun pts/44 Jul 31 14:16 (219.148.133.31) pts/44 Jul 31 14:16 (219.148.133.31)
duke1988 pts/45 Jul 31 14:41 (218.104.163.66) pts/45 Jul 31 14:41 (218.104.163.66)
liuzk423 pts/6 Jul 20 08:27 (219.245.104.240)
nefu_luyanshen pts/23 Jul 31 14:33 (218.25.6.142)
nefu_luyanshen pts/48 Jul 31 12:59 (218.25.6.142)
shuzigui pts/21 Jul 31 12:11 (121.35.248.193)
tomotoboy pts/41 Jul 31 13:31 (219.221.99.155)
waterlooz pts/25 Jul 31 08:48 (121.0.29.225)
wsoangel pts/35 Jul 31 13:40 (116.233.219.10)
xp55699312 pts/42 Jul 31 14:12 (61.152.132.103)
zyy0904 pts/43 Jul 31 13:53 (125.33.195.36)
-bash-3.00$ join -o 1.1 2.2 sed.txt sort.txt
605408211 pts/16
caodejun pts/44
duke1988 pts/45
-bash-3.00$ join -o 1.1 2.2 2.3 sed.txt sort.txt
605408211 pts/16 Jul
caodejun pts/44 Jul
duke1988 pts/45 Jul

• cut
cut用来从标准输入或文本文�g中剪切列或域。剪切文本可以将之粘贴到一个文本文件�?
下一节将介绍�_�脓(chu��ng)用法�?
cut一般格式�ؓ�Q?
cut [options] file1 file2
下面介绍其可用选项�Q?
-c list 指定剪切字符数�?
-f field 指定剪切域数�?
-d   指定与空格和t a b键不同的域分隔符�?
- c用来指定剪切范围�Q�如下所�C�：
- c 1�Q?-7 剪切�W?个字�W�，然后是第5到第7个字�W��?
-c1-50 剪切�? 0个字�W��?
-f 格式�? c相同�?
-f 1�Q? 剪切 �W?域，�W?域�?
- f 1�Q?0-12 剪切�W?域，�W? 0域到�W? 2域�?

-bash-3.00$ ps -ef | cut -c1-8
-bash-3.00$ ps -ef | cut -d: -f1
-bash-3.00$ ps -ef | cut -d: -f1�Q?

• paste
cut用来从文本文件或标准输出中抽取数据列或者域�Q�然后再�?paste可以��这些数据粘�?
��h��形成相关文�g。粘贴两个不同来源的数据�Ӟ��首先需��其分类�Q��ƈ��保两个文�g行数�?
同�?
paste��按行将不同文�g行信息放在一行。缺省情况下�Q?paste�q�接�Ӟ��用空格或tab键分�?
新行中不同文本，除非指定- d选项�Q�它?y��u)��成为域分隔�W�。paste格式为：
paste -d -s -file1 file2
选项含义如下�Q?
-d   指定不同于空格或t a b键的域分隔符。例如用@分隔域，使用- d @�?
-s   ��每个文件合�q�成行而不是按行粘贴�?
            - 使用标准输入。例如ls -l |paste �Q�意卛_��在一列上昄��输出�?

• split
split用来��大文�g分割成小文�g。有时文件越来越大，传送这些文件时�Q�首先将其分割可
能更�Ҏ(gu��)��。��用v i或其他工兯��如sort�Ӟ��如果文�g对于工作�~�冲区太大，也会存在一些问题�?
因此有时没有选择余地�Q�必��d��文�g分割成小的碎片�?
split命��o一般格式：
split -output_file-size input-filename output-filename
�q�里output_file-size 指的是文本文件被分割的行数�?
-bash-3.00$ ps -ef |split -10
-bash-3.00$ ls

a.out            greeting.sh      main.c           sort.txt         xac              xai              xao

append.sed       grepgrepstrings nohup.out        test             xad              xaj              xap

change.sed       grepstr          readme.sh        test.sh          xae              xak              xaq

core.log         hello            seawolf          user.online      xaf              xal              xar

factorial        hello.cpp        sed.out          xaa              xag              xam

factorial.c      main             sed.txt          xab              xah              xan

Gavin.lee 2009-11-29 11:57 发表评论

*	��L��字符�?/td>
�Q?/td>	��L��单字�W��?/td>
[..]	�c�L��范围中�Q意字�W��?/td>

-d	目录	-s	文�g长度大于0、非�I?/td>
-f	正规文�g	-w	可写
-L	�W�号�q�接	-u	文�g有suid位设�\|?/td>
-r	可读	-x	可执�?/td>

=	两个字符串相�{��?/td>
!=	两个字符串不�{��?/td>
-z	�I�Z��?/td>
-n	非空丌Ӏ?/td>

-eq	数值相�{��?/td>
-ne	数��g��相等�?/td>
-gt	�W�一个数大于�W�二个数�?/td>
-lt	�W�一个数��于�W�二个数�?/td>
-le	�W�一个数��于�{�于�W�二个数�?/td>
-ge	�W�一个数大于�{�于�W�二个数�?/td>

$0	$1	&2	$3	$4	$5	$6	$6	$7	$8	$9	${10}	${11}	……
脚本文�g�?	�W�一个参�?	�W�二个参�?	……

$#	传递到脚本的参��C��?/td>
$*	以一个单字符串显�C�所有向脚本传递的参数。与位置变量不同�Q�此选项参数可超�q?9�?/td>
$$	脚本�q�行的当前进�E�ID�?/td>
$!	后台�q�行的最后一个进�E�的�q�程ID�?/td>
$@	�?#相同�Q�但是��用时加引��P��q�在引号中返回每个参�?/td>
$-	昄��shell使用的当前选项�Q�与set命��o功能相同
$?	昄��最后命令的退出状态�?表示没有错误�Q�其他�Q何��D��明有错误�?/td>

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shell函数

控制���结构——until、while、break、continue

控制���结构——for

控制���结构——if then else

控制���结构——case

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登陆环境

控制��结构——until、while、break、continue

控制��结构——for

控制��结构——if then else

控制��结构——case