Issue#1 colliderscope.sh - bash sub-command failing

[codedChaos]

            # BUG: sub-command isn't functioning, throws a 'grep' is a garbage error
            # but if you run the cmd as it is without the outside (), it works just fine
            # need to scour forums and post a question on stack overflow
            # I'm sure it's something to do with the way variables and quotes are parsed and
            # interpolated in the sub-command
            NICS+=(${CMDs[IP]} link show | grep ^[^1]: | cut -d' ' -f2 | tr ':' '\n' | awk NF)

${IP_CMD} 
Error: either "dev" is duplicate, or "grep" is a garbage.

[codedChaos]

Using bash's 'eval' cmd against the variable holding the 'ip link show' command clears the issue. Why is that?

$   $IP_CMD
Error: either "dev" is duplicate, or "grep" is a garbage.
$   echo $IP_CMD
/usr/bin/ip link show | grep ^[^1]: | cut -d' ' -f2 | tr ':' ' '
$   eval $IP_CMD
enp0s31f6
wlp2s0