Shell finishing (31) = = = To determine if the input is IP

(title): Determine if the incoming parameter is IP

Idea: 192.168.1.1

is the condition of the IP, * * * dot decimal This four number must be less than 255

Dot decimal must be guaranteed to be a number, not a letter

#!/bin/bash[ -z $1 ] && echo  "uesage :  ' basename $0 '  ip " && exit 0check  ()  {         A= ' echo $1 | awk -f.  ' {if ($1<255 && $2<255 &&  $3<255 && $4<255) {print  "yes"} '          if echo $1|egrep  "^[0-9]{1,3}\. [0-9] {1,3}\. [0-9] {1,3}\. [0-9] {1,3}$ ">/dev/null        then             if [  $a  ==  "yes"  ]; then                 echo  "Yes"              else                 echo&nBSP; " No "           fi         else                 echo  "No"         fi}check $1

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Shell finishing (31) = = = To determine if the input is IP