Reads a file line-by-line and applies regex with two groups and checks if left string is present in right string

regex-substr.sh

#!/bin/bash
# Reads a file line-by-line and applies regex with two groups and checks if left string is present in right string

regex="([0-9]{10})#PHVN(.*)"

while IFS="" read -r p || [ -n "$p" ]
do
    line=$(printf '%s\n' "$p")
    if [[ $line =~ $regex ]]
    then
        needle="${BASH_REMATCH[1]}"
        hay="${BASH_REMATCH[2]}"
        if [[ ! "$hay" =~ "$needle" ]]; then
          echo "$line"
        fi
    fi
done < "$1"