My study notes and examples to remember how to use bash arrays.

Table of Contents

ref:

• http://www.tldp.org/LDP/abs/html/arrays.html
• http://www.thegeekstuff.com/2010/06/bash-array-tutorial
• http://www.yourownlinux.com/2016/12/bash-scripting-arrays-examples.html

Declare Array and Assigning Values

arr[index]=value

arr[0]='a'
arr[1]='b'
echo ${arr[1]}
  ## b

Initializing during declaration

Two options:

declare -a arr=(el1 el2)
arr=(el1 el2)

arr=('a' 'b')
echo ${arr[1]}
  ## b

Print all elements

echo ${arr[@]}
  ## a b

Read a File into an Array

arr=(`cat ./data/bash_sample_csv.csv`)
echo ${arr[@]}
  ## col1,col2 row11,row12 row21,row22

Loop over array

arr=('a' 'b')
for el in "${arr[@]}"; do 
  echo $el
done
  ## a
  ## b

Loop over a space separated string

str="a b"
for el in $str; do 
  echo $el
done
  ## a 
  ## b