Looking for regex to extract email addresses from /etc/passwd

user1:x:1147:5005:User One,Department,,,[email protected]:/home/directory:/bin/bash
user2:x:1148:5002:User Two,Department2,[email protected],:/home/directory:/bin/bash

awk -F : '{print $5}' /etc/passwd

awk -F , '{print $1}'

awk -F : '{print $5}' /etc/passwd | awk -F , '{print $1}'

sed -r -e "s/^.*[,:]([^,:]+@[^,:]+).*$/1/g" /etc/passwd

[a-z0-9!#$%&'*+/=?^_`{|}~-]+(?:.[a-z0-9!#$%&'*+/=?^_`{|}~-]+)*@(?:[a-z0-9](?:[a-z0-9-]*[a-z0-9])?.)+[a-z0-9](?:[a-z0-9-]*[a-z0-9])?

sed 's/,*:/.*//;s/^.*://;s/.*,//' /etc/passwd

(?:[a-z0-9!#$%&'*+/=?^_`{|}~-]+(?:.[a-z0-9!#$%&'*+/=?^_`{|}~-]+)*|"(?:[x01-x08x0bx0cx0e-x1fx21x23-x5bx5d-x7f]|\[x01-x09x0bx0cx0e-x7f])*")@(?:(?:[a-z0-9](?:[a-z0-9-]*[a-z0-9])?.)+[a-z0-9](?:[a-z0-9-]*[a-z0-9])?|[(?:(?:25[0-5]|2[0-4][0-9]|[01]?[0-9][0-9]?).){3}(?:25[0-5]|2[0-4][0-9]|[01]?[0-9][0-9]?|[a-z0-9-]*[a-z0-9]:(?:[x01-x08x0bx0cx0e-x1fx21-x5ax53-x7f]|\[x01-x09x0bx0cx0e-x7f])+)])