In this post, I'll show you how to use for loop on array of strings in bash. We will see several bash examples of foor loops.

for loop on array

In bash, we can use a for loop to iterate over an array of elements:

for i in US UK ID CH; do
	echo "$i"
done

This prints each element of the array on a new line:

US
UK
ID
CH

for loop on array - variable

Alternatively we can define array as variable and loop on it:

arr=("BR" "CH" "ID")

for i in "${arr[@]}"
do
   echo "$i"
done

BR
CH
ID

The ${arr[@]} syntax is used to access all elements of the array.

The "$i" inside the loop body refers to the current element of the array (processed in each iteration).

for loop on array - script

To create a shell script to loop over the list of strings we use this syntax:

#!/bin/bash
arr=("BR" "CH" "ID")

for mystr in "${arr[@]}"; do echo "$mystr"; done

We can save it as script file: script.sh and run it by:

./script.sh

BR
CH
ID

In the last section you can find if you face error: bash array Syntax error: "(" unexpected

for loop on array - append items

To append elements to an array and loop over it in bash use syntax: newarr=("${arr[@]}" "UK"):

#!/bin/bash
arr=("BR" "CH" "ID")

newarr=("${arr[@]}" "UK")

for mystr in "${newarr[@]}"; do echo "$mystr"; done

This will output:

BR
CH
ID
UK

bash array Syntax error: "(" unexpected

IN some terminals if you run this as bash script it may result into error:

bash array Syntax error: "(" unexpected

The error is caused by:

  • starting the script with
    • #!/bin/sh
    • #!/bin/bash
  • running the script with:
    • sh script.sh

To fix error bash array Syntax error: "(" unexpected remove the start and run it with: ./script.sh