package duplication present in (e.g.) a profile. It shows the
number of instances of each package in a closure, along with the
size in bytes of each instance as well as the "waste" (the
difference between the sum of the sizes of all instances and the
average size).
$ ./show-duplication.pl /nix/var/nix/profiles/default
gcc 11
3.3.6 19293318
3.4.4 21425257
...
average 14942970, waste 149429707
coreutils 6
...
average package duplication 1.87628865979381, total size 3486330471, total waste 1335324237, 38.3017114443825% wasted
This utility is useful for measuring the cost in terms of disk space
of the Nix approach.
files and hard-links them to each other to save disk space.
Currently it doesn't actually do the hard-linking, it just reports
the amount of space saved if it did.
