Question

I’m a newbie to Bourne shell and want to do simple array simulation. This works:

COLORS='FF0000 0000FF 00FF00'
i=2
color=$(echo ${COLORS} | awk '{print $2}')
echo "color selected: $color"

What I want to do is to pass $i instead of the fixed $2 parameter in print (this will later be used in a loop). I spent hours figuring out the right combination of single and double quotes to do this, no luck.

The closest I got is

color=$("echo ${COLORS} | awk '{print "$"${i}}'")

The run result is:

+ COLORS=FF0000 0000FF 00FF00
+ i=2
+ echo FF0000 0000FF 00FF00 | awk '{print $2}'
./tempgraph.sh: ./tempgraph.sh: 37: echo FF0000 0000FF 00FF00 | awk '{print $2}': not found
+ color=
+ echo color selected:
color selected:

Any help is appreciated.

Answer 1

I’d do it like this:

color=$(echo ${COLORS} | awk "{print \$$i}")

If you use '...', the content is not expanded. But you want the value of $i inserted in your script. So "..." is to be used, which does variable expanding. But you also want a $ in front of the number for AWK, so you’ve got to escape it (\$).