-mkdir -p /Maildir{cur,tmp,new}
-chgrp Debian-exim /Maildir{cur,tmp,new}
-chmod 775 /Maildir{cur,tmp,new}
-if id -g 1000 &>/dev/null; then
- usermod -a -G Debian-exim 1000
-fi
-if [[ -e /m/md ]]; then
- ln -s /Maildir /m/md/bounces
+dirs=(/Maildir/{cur,tmp,new})
+mkdir -p ${dirs[@]}
+chown -R $u:Debian-exim /Maildir
+chmod 775 ${dirs[@]}
+usermod -a -G Debian-exim $u
+if [[ -d /m/md ]]; then
+ sudo -u $u ln -sf -T /Maildir /m/md/bounces