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@gregmark
Forked from magnetikonline/README.md
Created March 7, 2021 00:48
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Bash array usage cheatsheet.

Bash array usage cheatsheet

Creation

# empty
myArray=()

# with elements
myArray=("first" "second" "third item" "fourth")

myArray=(
	"first"
	"second"
	"third item"
	"fourth"
)

Get elements

# all elements - space delimited
$ echo ${myArray[@]}

# all elements - separate words
$ echo "${myArray[@]}"

# all elements - single word, separated by first character of IFS
$ IFS="-"
$ echo "${myArray[*]}"

# specific element
$ echo "${myArray[1]}"

# two elements, starting at second item
$ echo "${myArray[@]:1:2}"

# keys (indicies) of an array
$ echo "${!myArray[@]}"

Append element

myArray=()
myArray+=("item")

Array length

# element count
$ echo "${#myArray[@]}"

# length of specific element (string length)
$ echo "${#myArray[1]}"

Iteration

for arrayItem in "${myArray[@]}"; do
	echo "$arrayItem"
done

Pass array to function

Note: Named reference to another variable (local -n) only supported with Bash 4.3.x or above.

function myFunction {
	local -n givenList=$1
	echo "${givenList[@]}"
}

itemList=("first" "second" "third")
myFunction itemList

Reference

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