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List Assignment If you are familiar with Perl, C, or Java, you might think that Bash would use commas to separate array elements, however this is not the case; instead, Bash uses spaces: # Array in Perl my @array = (1, 2, 3, 4); # Array in Bash array=(1 2 3 4) Create an array with new ...

Print element at index 0 echo "${array[0]}" 4.3 Print last element using substring expansion syntax echo "${arr[@]: -1 }" 4.3 Print last element using subscript syntax echo "${array[-1]}" Print all elements, each quoted separately echo "${array[@...

${#array[@]} gives the length of the array ${array[@]}: array=('first element' 'second element' 'third element') echo "${#array[@]}" # gives out a length of 3 This works also with Strings in single elements: echo "${#array[0]}" # gives out the lenght of the string at ele...

Change Index Initialize or update a particular element in the array array[10]="elevenths element" # because it's starting with 0 3.1 Append Modify array, adding elements to the end if no subscript is specified. array+=('fourth element' 'fifth element') Replace the entire ar...

Array iteration comes in two flavors, foreach and the classic for-loop: a=(1 2 3 4) # foreach loop for y in "${a[@]}"; do # act on $y echo "$y" done # classic for-loop for ((idx=0; idx < ${#a[@]}; ++idx)); do # act on ${a[$idx]} echo "${a[$idx]}&...

To destroy, delete, or unset an array: unset array To destroy, delete, or unset a single array element: unset array[10]

4.0 Declare an associative array declare -A aa Declaring an associative array before initialization or use is mandatory. Initialize elements You can initialize elements one at a time as follows: aa[hello]=world aa[ab]=cd aa["key with space"]="hello world" You can al...

Get the list of inialized indexes in an array $ arr[2]='second' $ arr[10]='tenth' $ arr[25]='twenty five' $ echo ${!arr[@]} 2 10 25

Our example array: arr=(a b c d e f) Using a for..in loop: for i in "${arr[@]}"; do echo "$i" done 2.04 Using C-style for loop: for ((i=0;i<${#arr[@]};i++)); do echo "${arr[$i]}" done Using while loop: i=0 while [ $i -lt ${#arr[@]} ]; do...

stringVar="Apple Orange Banana Mango" arrayVar=(${stringVar// / }) Each space in the string denotes a new item in the resulting array. echo ${arrayVar[0]} # will print Apple echo ${arrayVar[3]} # will print Mango Similarly, other characters can be used for the delimiter. stringVa...

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 #...

Reading in a single step: IFS=$'\n' read -r -a arr < file Reading in a loop: arr=() while IFS= read -r line; do arr+=("$line") done 4.0 Using mapfile or readarray (which are synonymous): mapfile -t arr < file readarray -t arr < file