apg is a handy utility for creating random passwords / strings. To install it run:

apt-get install apg

The below for loop will create 300 random usernames / email addresses in the format username@domain.com. You can always replace “domain” with “$i” , then you’ll have addresses in the format username@username.com.

-M – specifies that mode will be used
L – use small letters only mode
-n – number of passwords/random strings, in this case 300

for i in $(apg -M L -n 300); do echo $i@domain.com >> fileToSaveResult ; done