There are times when it is desirable to determine programmatically whether a an IP Address is valid or not. This little BASH code snippet does exactly that. The return code will be 0 if it is a valid IP address and 1 if not.<\/p>\n
\n\n################################################################################\n# Determine whether an arbitrary set of four octets of numeric data separated #\n# by periods is a valid IP address.\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 #\n# Note: This code was taken from Linux Journal June 26, 2008\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 #\n# http:\/\/www.linuxjournal.com\/content\/validating-ip-address-bash-script<\/a> #\n################################################################################ \nvalid_ip() \n{\n local ip=$1\n local\n stat=1\n # Check the IP address under test to see if it matches the extended REGEX\n if [[ $ip =~ ^[0-9]{1,3}\\.[0-9]{1,3}\\.[0-9]{1,3}\\.[0-9]{1,3}$ ]]\n then\n # Record current default field separator\n OIFS=$IFS\n # Set default field separator to .\n IFS='.'\n # Create an array of the IP Address being tested\n ip=($ip)\n # Reset the field separator to the original saved above IFS=$OIFS\n # Is each octet between 0 and 255?\n [[ ${ip[0]} -le 255 && ${ip[1]} -le 255 && ${ip[2]} -le 255 && ${ip[3]} -le 255 ]]\n # Set the return code.\n stat=$?\n fi\n}\n\n<\/span><\/pre>\n<\/blockquote>\n","protected":false},"excerpt":{"rendered":"There are times when it is desirable to determine programmatically whether a an IP Address is valid or not. This little BASH code snippet does exactly that. The return code will be 0 if it is a valid IP address…<\/p>\n