Shell Regular expression authentication IP address _linux shell

Multiple IP on this machine

Copy Code code as follows:

Ifconfig | awk '/inet/{print $} ' | Awk-f: ' {print $} '

First, use this first.

Copy Code code as follows:

Checkipaddress ()
{
echo $ >/tmp/tmpserverip
echo $ |grep "^[0-9]\{1,3\}\. [0-9]\{1,3\}\. [0-9]\{1,3\}\. [0-9]\{1,3\}$ >/dev/null
If [$? = 1]; Then
Return 1
Else
a=$ (cut-d.-f1/tmp/tmpserverip)
b=$ (cut-d.-f2/tmp/tmpserverip)
c=$ (cut-d.-f3/tmp/tmpserverip)
d=$ (cut-d.-f4/tmp/tmpserverip)

For the loop in $a $b $c $d
Todo
If [$loop-ge 255] | | [$loop-le 0]; Then
Return 2
Fi
Done
Fi

return 0
}

At first, refer to the following

Copy Code code as follows:

grep "^" ([01]?\d\d?| 2[0-4]\D|25[0-5]) \. ([01]?\d\d?| 2[0-4]\D|25[0-5]) \. ([01]?\d\d?| 2[0-4]\D|25[0-5]) \. ([01]?\d\d?| 2[0-4]\D|25[0-5]) \.$ "

Input IP, check whether it is satisfied with the IP writing specification, that is, can not be greater than 255, can not have letters, and other punctuation, reference on the Internet, they made a following, make a mark! @

Copy Code code as follows:

Echo-n ' Enter the Server-ip: '
Read Bissip
echo $BISSip >/tmp/tmpserverip
echo $BISSip |grep "^[0-9]\{1,3\}\. [0-9]\{1,3\}\. [0-9]\{1,3\}\. [0-9]\{1,3\}$ >/dev/null
Num=$?
if [$num = 1]
Then
echo Error Ip,please Enter correct

Else
{
a=$ (cut-d.-f1/tmp/tmpserverip)
b=$ (cut-d.-f2/tmp/tmpserverip)
c=$ (cut-d.-f3/tmp/tmpserverip)
d=$ (cut-d.-f4/tmp/tmpserverip)

{
If [$a-ge 255]| | [$a-le 0]
Then
echo A:error IP
Else
Echo 1 >/tmp/jack
Fi
}

{
If [$b-ge 255]| | [$b-lt 0]
Then
echo B:error IP
Else
Echo 1 >>/tmp/jack
Fi

}

{if [$c-ge 255]| | [$c-lt 0]
Then
echo C:error IP
Else
Echo 1 >>/tmp/jack
Fi
}

{if [$d-ge 255]| | [$d-le 0]
Then
echo D:error IP
Else
Echo 1 >>/tmp/jack
Fi
}