I would like to be able to tell how much disk space I have used and how much I have available (in GB) in Big Sur in a simple format suitable for parsing in a shell script or similar.
Finder reports that my internal SSD is 995 GB and has 568 GB free.
Simple math tells us that means I have used 427 GB.
So… how can I get
568 GB and/or
427 GB from the command line?
Hint: The answer is not
If I do
df -H / I will get this result (truncated for readability and to just the parts of the output we care about):
Filesystem Size Used Avail Capacity /dev/disk3s1s1 995G 15G 528G 3%
15G might be how much the read-only volume takes up, but the “available” amount is off by 40G.
Of course we know that there’s now a separate ‘Data’ volume. So let’s check that using
df -H /System/Volumes/Data:
Filesystem Size Used Avail Capacity /dev/disk3s5 995G 445G 528G 46%
445G used is relatively close to the actual amount of
427G but if you add up the “Used” (445G) and “Available” (528G) you get 973G.
There must be some way to do it…
I have noticed that other apps such as iStat Menus and MakeMKV are both able to display accurate information about the remaining disk space. So it’s not as if the system is incapable of revealing this information.
If there is another tool besides
df that can do this, please let me know.
Bonus points if it comes standard with macOS (bash, zsh, python, ruby, whatever), but if it can be installed via
brew or similar, I’ll take it.
What I’m asking for seems very simple, but I can’t figure out how to do it.
p.s. - yes, I’m aware of macOS’ features about “purgeable space” and all that. Not interested. I just want to be able to get the same numbers shown in Finder, iStat Menus, etc. from the command line.