Change Index

Initialize or update a particular element in the array

array[10]="elevenths element"    # because it's starting with 0


Modify array, adding elements to the end if no subscript is specified.

array+=('fourth element' 'fifth element')

Replace the entire array with a new parameter list.

array=("${array[@]}" "fourth element" "fifth element")

Add an element at the beginning:

array=("new element" "${array[@]}")


Insert an element at a given index:

arr=(a b c d)
# insert an element at index 2
arr=("${arr[@]:0:$i}" 'new' "${arr[@]:$i}")
echo "${arr[2]}" #output: new


Delete array indexes using the unset builtin:

arr=(a b c)
echo "${arr[@]}"   # outputs: a b c
echo "${!arr[@]}"  # outputs: 0 1 2
unset -v 'arr[1]'
echo "${arr[@]}"   # outputs: a c
echo "${!arr[@]}"  # outputs: 0 2


array3=("${array1[@]}" "${array2[@]}")

This works for sparse arrays as well.

Re-indexing an array