df numbers not adding up (Big Sur) I have a MBP with a 1 terabyte SSD. If I look at the storage tab of about this mac, it looks like I would expect, but if I run df -h from the terminal, I get:
Filesystem       Size    Used   Avail   Capacity   iused       ifree         %iused  Mounted on
/dev/disk1s1s1   932Gi   14Gi   83Gi    15%        568975      9767409185    0%   /

Is this a bug in df on Big Sur, or should I be worried that something is up with my MBP? On my old computer (which never get past Mojave) the numbers added up and looked right.
You should not be worried.  There is no bug.
You should show all the output from df -h | grep disk1s. The line with disk1s1s1 refers to the currently used snapshot of the read-only boot volume.  In which case the 14Gi is the expected used.