To list files that were changed in the last day, sorted by size, using Apple’s Terminal, or any Unix / Linux bash shell: sudo find / -type f -mtime -1 -print0 | xargs -0 du -sk | sort -nr(thanks mynamewasgone!)

Command breakdown

(:TODO: code formatter)

sudo

run in superuser mode – allows you to reach hidden system folders (if that’s what you need). You’ll be asked for your password

find /

use the powerful find command, starting from the root of the computer – in other words, search everywhere (which may not be a good idea if you are connected to a network or have a massive hard disk connected to your machine)

-type f

only look for files…

-mtime -1

…modified less than a day ago

-print0

when files are found, spit them out in a list with a NULL at the end instead of a new line – this helps with the next step

|

pass the list generated by find to the next command…

xargs -0

…which is xargs, used to take a list of results and pass them on. The -0 is telling xargs to use NULL as the separator

du -sk

use du to show how much space the files take, in kilobytes

|

pass the list generated by find to the next command…

sort -nr

…which sorts the list in reverse numerical order using sort

Find -exec is slow

Originally I did everything within find, using the -exec flag.
sudo find / -type f -mtime -1 -exec du -sk {} \; | sort -nrBut as mynamewasgone pointed out, find -exec is slow