Bash Array Assignments


Example

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 elements:

array=('first element' 'second element' 'third element')

Subscript Assignment

Create an array with explicit element indices:

array=([3]='fourth element' [4]='fifth element')

Assignment by index

array[0]='first element'
array[1]='second element'

Assignment by name (associative array)

4.0
declare -A array
array[first]='First element'
array[second]='Second element'

Dynamic Assignment

Create an array from the output of other command, for example use seq to get a range from 1 to 10:

array=(`seq 1 10`)

Assignment from script's input arguments:

array=("$@")

Assignment within loops:

while read -r; do
    #array+=("$REPLY")     # Array append
    array[$i]="$REPLY"     # Assignment by index
    let i++                # Increment index 
done < <(seq 1 10)  # command substitution
echo ${array[@]}    # output: 1 2 3 4 5 6 7 8 9 10

where $REPLY is always the current input