@cassidoo's 20220717 interview question

hideEmail.sh

#!/usr/bin/env bash
set -eu -o pipefail

# substitute asterisks for all but first and last characters of string
obscureString () {
	str="$1"
	ret="${str:0:1}$( printf "%0.s*" $( seq 1 $(( ${#str}-2 )) ) )${str: -1}"
	echo $ret
}

# check for one param split with '@'
if [ $# -eq 0 ] || [ $# -gt 2 ] || [[ ! "$1" =~ ^.*@.*[^@]$ ]]; then
  echo "$(basename "$0"): enter a valid email address"
  exit 1
fi
local_part=$( cut -d '@' -f 1 <<< "$1" )
domain=$( cut -d '@' -f 2 <<< "$1" )

# let's make sure the domain is legit
if dig $domain | grep "ANSWER: 0" 1>/dev/null; then
	echo "$domain is not valid"
	exit 1
fi

# substitute asterisks for middle portion of local_part
local_part_subbed=$( obscureString "$local_part" )

if [ $# -gt 1 ] && [[ "${2,,}" == "hidefull" ]]; then
	# substitute asterisks for middle portion of domain
	domain_subbed=$( obscureString "$domain" )
	echo "${local_part_subbed}@${domain_subbed}"
else
	echo "${local_part_subbed}@${domain}"
fi

MONTASIO:~ andrewrich$ ~/Documents/scripts/hideEmail.sh [email protected]
a*********[email protected]
MONTASIO:~ andrewrich$ ~/Documents/scripts/hideEmail.sh [email protected] hidefull
a*********h@g*******m
MONTASIO:~ andrewrich$ ~/Documents/scripts/hideEmail.sh [email protected]
fakemail.fake is not valid