Adding a prefix to all array elements in Bash

Question

I am storing command line parameters in an array variable. (This is necessary for me). I wanted to prefix all the array values with a string passing through a variable.

PREFIX="rajiv"

services=$( echo $* | tr -d '/' )

echo  "${services[@]/#/$PREFIX-}"

I am getting this output.

> ./script.sh webserver wistudio
rajiv-webserver wistudio

But I am expecting this output.

rajiv-webserver rajiv-wistudio

Answer 1

Your array initialization is wrong. Change it to this:

services=($(echo $* | tr -d '/'))

Without the outer () , services would become a string and the parameter expansion "${services[@]/#/$PREFIX-}" adds $PREFIX- to your string.

In situations like this, declare -p can be used to examine the contents of your variable. In this case, declare -p services should show you:

declare -a services=([0]="webserver" [1]="wistudio") # it is an array!

and not

declare -- services="webserver wistudio"             # it is a plain string