Raspberry Pi Stack Exchange is a question and answer site for users and developers of hardware and software for Raspberry Pi. It only takes a minute to sign up.
Sign up to join this community
Which directories of a Raspbian installation can be deleted so that disk space is freed, but Raspbian is still able to boot onto desktop.
Backstory: I recorded with Audacity and forgot to turn recording off. So Audacity filled the whole SD card with silence and crashed. The Raspberry Pi does not boot onto desktop anymore, but I can access via SSH. So I hope to recover the session, but I need the Raspi to safely boot onto desktop again, therefore trying to recover a little space on the card.
System directories don't exist for no reason, so don't start deleting them willy-nilly.
If you did this as user pi, chances are the data is in /home/pi somewhere, but sometimes applications will also use /tmp as it is world writable, or somewhere in /var if they have a writable location there.1 Commonly /tmp is actually a small, in memory directory (meaning it won't hold much and does not persist across boots) but I believe this is not the case by default on current versions of Raspbian (there are a few similar things though; you can check for such directories with mount | grep "^tmpfs" -- but these are obviously not the problem here).
A good tool for finding this kind of thing is du; this will give you per directory totals for a tree, e.g.:
> du -h /home/pi/temp
11.4M /home/pi/temp/bearPics/candid_poses
19M /home/pi/temp/bearPics
172K /home/pi/temp/foobarTutorial
9.0M /home/pi/temp/sunshine
28M /home/pi/temp/
The -h provides more "human" digestible numbers (with units). Here you can see /home/pi/temp contains a total of 28 MB, most of it in bearPics, most of that in bearPics/candid_poses.
With large trees, it may be easier to use du -h -d 1, where the -d 1 means to show just 1 level deep; you can then analyze individual subdirectories from there. If you want to get really fancy (thanks stevieb from comments below):
du -h /home/pi | sort -n -r | head -n 10
Will show you the top 10 largest directories in descending order; logically the top one will be /home/pi, since it includes everything inside.
Don't try this on / as it will take a long time. You can try it on /home/pi, which will probably give you a long list (somewhere -d 1 might help) but the last line is always the grand total, meaning it is easy to tell whether this is the place or not.
If not check /var and /tmp. There is more information on du in man du.
1. If it is outside of /home, don't delete the actual directory when you find it unless it is owned by the user whose data it contains; just delete the fat data files inside. Otherwise the application may not be able to recreate the (possibly system wide) data directory when run as a normal user.
lsof | grep -i deleted. Any large ones in there can be safely deleted, as they are simply files that were deleted by processes, but the process may still be running. I can't remember if lsof is installed by default, but a sudo apt-get install lsof will fix that
– stevieb
Sep 22 '16 at 13:28
du -h /home/pi | sort -n -r | head -n 10. That'll show the 10 largest files, by size in descending order
– stevieb
Sep 22 '16 at 13:36
lsof as deleted, they are already flagged for deletion, but have not yet been removed from disk because the process that deleted them has not yet freed them. This problem is very common with things like web servers, where they delete their own large log files, but aren't freed from disk yet because the process hasn't yet been restarted since the delete.
– stevieb
Sep 22 '16 at 14:05
lsof is unlikely to be useful.
– Dmitry Grigoryev
Sep 22 '16 at 14:06
According to documentation, Audacity saves its files in /var/tmp/audacity-<your username>. That should be the first candidate for cleanup.
While strictly not directories as asked in the question, I will answer with the understanding that recovering some free disk space is the intent. Depending on how many packages' debs have been cached, you could gain nothing, something or a lot of disk space using apt-get autoclean. this thread has some relevant discussion on the topic. Be sure read and understand what the various options apt-get supports before executing the commands.
sshdstill works; this means root can still log in and fix the problem. It won't make any difference to say, "We'll reserve this much of the filesystem for Bob so Bob can use it after Bob has used everything else Bob could use" -- once Bob's used all the space Bob could use first Bob will just use the space Bob can now use second. – goldilocks♦ Sep 22 '16 at 20:04~/.Xauthorityfile as your user. It's only a handful of bytes but more than zero (and the fs uses 4K blocks anyway). – goldilocks♦ Sep 22 '16 at 20:10