How can I delete a folder with lots of subfolders fast?

Question

I have a folder with 266778 subfolders. How can I delete it?

I have tried

cd ~/.local/share/Trash/
sudo rm -rf *

but it takes much time. After 1 minute 25 seconds real time and 0.072 seconds user time it only deleted 2500 folders. This way, it will take over two hours to delete this folder.

Is there a faster way to delete this folder? Why is there such a big difference between user time and real time?

real    1m25.474s
user    0m0.072s
sys     0m28.142s

I use Linux 2.6.32 (Ubuntu 10.04.4 LTS).

Answer 1

If your version of "find" implements the -delete sub-command, then you can try

find directory -delete

In this case:

find ~/.local/share/Trash/ -delete

Some commands, like rm, perform most of their work in the kernel. In the file-system routines, to be exact. Time spent performing system calls are accounted for in that way, so whilst your "rm" command runs for a long time, it doesn't do much work in user-land - the system calls performs most of the work.

Answer 2

It depends on your definition of fast. The answers already here give a good solution for actually removing the directories from the filesystem, but if what you really need is to free the directory name as fast as possible, a rename on the same filesystem is instantaneous:

{ mv directory directory.gone && rm -rf directory.gone; } &

Technically this is cheating since I haven't sped up the actual deletion, but practically it's very useful: I use this trick all the time so I don't have to wait for slow deletion operations.

Answer 3

This is only a partial answer, sheding light on the three values the command returns; quoted from the time(1) manpage:

(i) the elapsed real time between invocation and termination, (ii) the user CPU time (the sum of the tms_utime and tms_cutime values in a struct tms as returned by times(2)), and (iii) the system CPU time (the sum of the tms_stime and tms_cstime values in a struct tms as returned by times(2))."