Change output format of "top" command in Mac OS for memory usage? I am using the top command in Mac OS from this answer to grab memory usage:

$ top -l 1 -s 0 | grep PhysMem

PhysMem: 5490M used (2569M wired), 11G unused.


Can I go from that to possibly printing out "Used / Total"?

Like so:

PhysMem: 5.49G / 16.0G  


or just:  

5.49G / 16.0G


Side questions:

Would that final top command be suitable to run in a few second interval and the output used for something later? Or is this not the best or most efficient command for grabbing this info and I should use something else? 

I am basically trying to replicate what Luke Smith did in his video, but in Mac OS for fun, and so I can try to learn this stuff.
A bit verbose, but the following awk snippet does this

$ echo 'PhysMem: 5490M used (2569M wired), 11G unused.' \
  | awk 'BEGIN {S["G"]=1024; S["M"]=1} 
         /PhysMem:/ {U=substr($2, 1, length($2)-1) * S[substr($2, length($2))];
                     N=substr($6, 1, length($6)-1) * S[substr($6, length($6))];
                     printf("%.2fG / %.2fG\n", U/1024, (N+U) / 1024)}'


5.36G / 16.36G