Question

I have two variables which have values that can be in both. I would like to create a unique list from the two variables.

VAR1="SERVER1 SERVER2 SERVER3"
VAR2="SERVER1 SERVER5"

I am trying to get a result of:

"SERVER1 SERVER2 SERVER3 SERVER5"

Answer 1

The following pipes a combination of the two lists through the sort program with the unique parameter -u:

UNIQUE=$(echo "$VAR1 $VAR2" | tr ' ' '\n' | sort -u)

This gives the output:

> echo $UNIQUE
SERVER1 SERVER2 SERVER3 SERVER5

Edit:

As William Purcell points out in the comments below, this separates the strings by new-lines. If you wish to separate by white space again you can pipe the output from sort back through tr '\n' ' ':

> UNIQUE=$(echo "$VAR1 $VAR2" | tr ' ' '\n' | sort -u | tr '\n' ' ')
> echo "$UNIQUE"
SERVER1 SERVER2 SERVER3 SERVER5