Arrays in Bash (Cheatsheet)

Description	Indexed array	Associative array
Declare an array	declare -a array	declare -A array
Assignment	array=(value1 value2 … valuen)	array=([sub1]=value1 … [subN]=valueN) Note:You must declare it first you can use declare -A array=([sub1]=value1 … [subN]=valueN)
Expand to all values	${array[@]}  or ${array[*]}	${array[@]}  or ${array[*]}
Expand to all keys	${!array[@]}  or ${!array[*]}	${!array[@]}  or ${!array[*]}
length of an array	${#array[@]} or ${#array[*]}	${#array[@]} or ${#array[*]}
Remove entire array	unset array or unset array[@] or unset array[*]	unset array or unset array[@] or unset array[*]
Remove an element	unset array[index]	unset array[index]
Array join	array1+=(${array2[@]}) or array1+=(v1 v2 … vN)	array1+=([sub1]=v1 [sub2]=v2 … [subN]=vN)
Length of an element:	${#array[index]}	${#array[index]}

 

Resources

http://tldp.org/LDP/abs/html/arrays.html