linux中特殊的参数变量

1. 参数计数

特殊变量$#可以存储执行脚本时包含的命令行参数个数！

#!/bin/bash

if [ $# -ne 2 ]

then

echo Usage:input a b

else

total=$[ $1 + $2 ]

echo The total is $total

fi

[[email protected] ~]# ./test33.sh 3 4

The total is 7

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

当要获取$#参数的最后面那个参数时，可以用${!#}命令

#!/bin/bash

params=$#

echo The toal parameters is $params

echo The last parameters is ${!#}

[[email protected] ~]# ./test34.sh 3

The toal parameters is 1

The last parameters is 3

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

获取所有数据

$* 将命令行中提供的所有参数作为一个单词处理，这个单词中包含出现在命令行中的每个参数值

[email protected] 将命令行中提东的所有参数作为同一个字符串中的多个单词处理

#!/bin/bash

#testing $* and [email protected]

echo "Using the \$* method: $*"

echo "Using the \[email protected] method: [email protected]"

count=1

for parm in "$*"

do

echo "\$* Parameters #$count = $parm"

count=$[ $count + 1 ]

done

count=1

for parm in "[email protected]"

do

echo "\[email protected] Parameters #$count = $parm"

count=$[ $count + 1 ]

done

[[email protected] ~]# ./test35.sh jack tom bot luck haha

Using the $* method: jack tom bot luck haha

Using the [email protected] method: jack tom bot luck haha

$* Parameters #1 = jack tom bot luck haha

[email protected] Parameters #1 = jack

[email protected] Parameters #2 = tom

[email protected] Parameters #3 = bot

[email protected] Parameters #4 = luck

[email protected] Parameters #5 = haha

$*:看做一个单词

[email protected]:分别对待每个参数