Difference between array[@] and array[*] in shell

It is important for quoting and spacing that the ${array[@]}
format (rather than ${array[*]}) is used, and also that double quotes are put around the whole construct. 

items=(pen "permanent marker" pencil "temporary marker")

 
for item in ${items[@]}
do
  echo "Item is : $item"
done

Item is : pen
Item is : permanent
Item is : marker
Item is : pencil
Item is : temporary
Item is : marker

for item in ${items[*]}
do
  echo "Item is : $item"
done

Item is : pen
Item is : permanent
Item is : marker
Item is : pencil
Item is : temporary
Item is : marker


items[@] and items[*] produced the same output and which is not expected. "permanent" and "marker" are treated as two different words in both the cases though it is a single word. lets try now with the quotes around the array..

items=(pen "permanent marker" pencil "temporary marker")

for item in "${items[@]}"
do
  echo "Item is : $item"
done

Item is : pen
Item is : permanent marker
Item is : pencil
Item is : temporary marker
 
 YES this what we expected.... but items[*] will not behave this way.

for item in "${items[*]}"
do
  echo "Item is : $item"
done

Item is : pen permanent marker pencil temporary marker


the * is not suitable either with or without quotes. Without quotes, it does the same as the @ symbol. With quotes, the whole array is boiled down into a single string.

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