I have a useradd bash script which requests the user enter an e-mail address for the user being created. This is so the user receives his username/password in an e-mail when his/her account is created. Currently this part of the code is very simple: echo Enter the users e-mail address read ADDRESS What i'm finding is that sometimes when the operators run the script they are entereing blank information. How can I put a if statement in place that enforces they enter an e-mail address format. I tried the following code but it doesn't work. The idea was to at least verify they are using the @ symbol. string=@ if [[ $string != "@" ]] ; then echo You have entered an invalid e-mail address! exit 1 else do something