I have written a script to add chrooted sFTP users.

The useradd command is:

sudo useradd -Ng sftponly -ms /bin/false "$USER"

Did it work?

groups $USER

$USER : sftponly

Yes it did. Great!

Then I take a look at /etc/group and there is no $USER in sftponly. I try logging in and out (shouldn't need to - I am not $USER) and nothing changes. (for $USER == yoko):

ftp:x:114:

sftponly:x:1003:george,john,paul,ringo

incron:x:115:

Why am I seeing $USER in the correct group when using groups, but not in /etc/group?