grep -xFq "$line" $f || tee -a $f <<<"$line"
-# default debian groups (jessie through buster) + adm, sudo, root, admin
+# default debian groups (jessie through buster) + adm, root, admin
for g in cdrom floppy audio dip video plugdev netdev adm sudo admin; do
if getent group $g >/dev/null; then
usermod -aG $g iank