Removing duplicates on a variable without sorting

Question

I have a variable that contains the following space separated entries.

variable=\"apple lemon papaya avocado lemon grapes papaya apple avocado mango banana\"         


        

Answer 1

Another awk solution:

#!/bin/bash
variable="apple lemon papaya avocado lemon grapes papaya apple avocado mango banana"
variable=$(printf '%s\n' "$variable" | awk -v RS='[[:space:]]+' '!a[$0]++{printf "%s%s", $0, RT}')
variable="${variable%,*}"
echo "$variable"

Output:

apple lemon papaya avocado grapes mango banana