The following shell script is used to check if the input IP

rs=1 while t Srs -gt o 1: do clear echo -n \"Please input the ip: read ip #use egrep to check if the input IP address follows the IP address pattern if $isIP then a=\"echo bs\'echo c=\"echo d=\"echo $ip $ip $ip $ip | awk l awk | awk l awk -F. -F- -F . -F· \'{print \'{print . {print \"(print $1}\'. $2 $3)\' $4}\'. isvalid=0; for n in $a $b $c $d; do if [ li then -o echo \"ERROR: The number of the IP should not be greater than 255 and less than 0\" break; fi done if [ fi ); then echo\"--This is a valid IP\" \" else echo \"ERROR: The IP format you input is wrong, the format should be like 192.168.100.1\" fi echo echo -n \"press 0 to exit and other numbers to continue...\" read done

Solution

Writing in order, the input was provided:

isip = \'egrep -q \'^[0-9]{1,3}\\.[0-9]{1,3}\\.[0-9]{1,3}\\.[0-9]{1,3}$\'

if [ ($n>255) -o ($n<0) ]; then

isValid = 1

if [ $isValid -ne 1 ]; then

read -n rs