Linux Shell命令（四） 循环语句 函数

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for 变量 in 列表
do
    command1
    command2
    ...
    commandN
done

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#!/bin/bash
for loop in 1 2 3 4 5
do
    echo "The value is: $loop"
done

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The value is: 1
The value is: 2
The value is: 3
The value is: 4
The value is: 5

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#!/bin/bash
for str in This is a string
do
    echo $str
done

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This                                                                             
is                                                                               
a                                                                                
string

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while command
do
   Statement(s) to be executed if command is true
done

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#!/bin/bash
COUNTER=0
while [ $COUNTER -lt 5 ]
do
    COUNTER=`expr $COUNTER + 1`
    echo $COUNTER
done

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1
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5

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#!/bin/bash
echo 'type <CTRL-D> to terminate'
echo -n 'enter your most liked film: '
while read FILM
do
    echo "Yeah! great film the $FILM"
done

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type <CTRL-D> to terminate
enter your most liked film: Sound of Music
Yeah! great film the Sound of Music

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until command
do
   Statement(s) to be executed until command is true
done

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#!/bin/bash
a=0
until [ ! $a -lt 5 ]
do
   echo $a
   a=`expr $a + 1`
done

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0
1
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4

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#!/bin/bash
while :
do
    echo -n "Input a number between 1 to 5: "
    read aNum
    case $aNum in
        1|2|3|4|5) echo "Your number is $aNum!"
        ;;
        *) echo "You do not select a number between 1 to 5, game is over!"
            break
        ;;
    esac
done

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#!/bin/bash
for var1 in 1 2 3
do
   for var2 in 0 5
   do
      if [ $var1 -eq 2 -a $var2 -eq 0 ]
      then
         break 2
      else
         echo "$var1 $var2"
      fi
   done
done

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1 0
1 5

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#!/bin/bash
while :
do
    echo -n "Input a number between 1 to 5: "
    read aNum
    case $aNum in
        1|2|3|4|5) echo "Your number is $aNum!"
        ;;
        *) echo "You do not select a number between 1 to 5!"
            continue
            echo "Game is over!"
        ;;
    esac
done

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function_name () {
    list of commands
    [ return value ]
}

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function function_name () {
    list of commands
    [ return value ]
}

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#!/bin/bash
# Define your function here
Hello () {
   echo "Url is http://www.hubwiz.com"
}
# Invoke your function
Hello

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/bin/bash test_function 
Url is http://www.hubwiz.com

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#!/bin/bash
funWithReturn(){
    echo "The function is to get the sum of two numbers..."
    echo -n "Input first number: "
    read aNum
    echo -n "Input another number: "
    read anotherNum
    echo "The two numbers are $aNum and $anotherNum !"
    return $(($aNum+$anotherNum))
}
funWithReturn
# Capture value returnd by last command
ret=$?
echo "The sum of two numbers is $ret !"

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The function is to get the sum of two numbers...
Input first number: 25
Input another number: 50
The two numbers are 25 and 50 !
The sum of two numbers is 75 !

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#!/bin/bash
funWithParam(){
    echo "The value of the first parameter is $1 !"
    echo "The value of the second parameter is $2 !"
    echo "The value of the tenth parameter is $10 !"
    echo "The value of the tenth parameter is ${10} !"
    echo "The value of the eleventh parameter is ${11} !"
    echo "The amount of the parameters is $# !"  # 参数个数
    echo "The string of the parameters is $* !"  # 传递给函数的所有参数
}
funWithParam 1 2 3 4 5 6 7 8 9 34 73

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The value of the first parameter is 1 !
The value of the second parameter is 2 !
The value of the tenth parameter is 10 !
The value of the tenth parameter is 34 !
The value of the eleventh parameter is 73 !
The amount of the parameters is 12 !
The string of the parameters is 1 2 3 4 5 6 7 8 9 34 73 !

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#!/bin/bash
# Calling one function from another
number_one () {
   echo "Url_1 is http://www.baidu.com/cpp/shell/"
   number_two
}
number_two () {
   echo "Url_2 is http://www.baidu.com/cpp/u/xitong/"
}
number_one

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Url_1 is http://www.baidu.com/cpp/shell/
Url_2 is http://www.baidu.com/cpp/u/xitong/