How To Append Lines To File If They Do Not Exist

 1FILE=/etc/samba/smb.conf
 2
 3LINES=$(cat <<EOF
 4[scan]
 5Comment = Scans
 6Path = /var/scan
 7Browseable = yes
 8Writeable = Yes
 9only guest = no
10guest ok = no
11create mask = 0777
12directory mask = 0777
13Public = no
14EOF
15)
16
17grep -q "${LINES}" ${FILE} && echo "Nothing to do" || \
18    echo "${LINES}" | tee -a ${FILE}