Special parameter variables in Linux

1. Parameter count
   

Special Variable $ #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=$[$ + $]

echo the total is $total

Fi

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

The total is 7

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When you want to get the $ #参数的最后面那个参数时, you can use the ${!#} command

#!/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

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Get all data

$* all arguments provided on the command line as a single word that contains each parameter value that appears on the command line

[email protected] handles all the arguments in the command line as multiple words in the same string

#!/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

$*: As a word

[Email protected]: treat each parameter separately

Special parameter variables in Linux