Example
This function will insert an element into an array at a given index:
insert(){
h='
################## insert ########################
# Usage:
# insert arr_name index element
#
# Parameters:
# arr_name : Name of the array variable
# index : Index to insert at
# element : Element to insert
##################################################
'
[[ $1 = -h ]] && { echo "$h" >/dev/stderr; return 1; }
declare -n __arr__=$1 # reference to the array variable
i=$2 # index to insert at
el="$3" # element to insert
# handle errors
[[ ! "$i" =~ ^[0-9]+$ ]] && { echo "E: insert: index must be a valid integer" >/dev/stderr; return 1; }
(( $1 < 0 )) && { echo "E: insert: index can not be negative" >/dev/stderr; return 1; }
# Now insert $el at $i
__arr__=("${__arr__[@]:0:$i}" "$el" "${__arr__[@]:$i}")
}
Usage:
insert array_variable_name index element
Example:
arr=(a b c d)
echo "${arr[2]}" # output: c
# Now call the insert function and pass the array variable name,
# index to insert at
# and the element to insert
insert arr 2 'New Element'
# 'New Element' was inserted at index 2 in arr, now print them
echo "${arr[2]}" # output: New Element
echo "${arr[3]}" # output: c
