Unix: fast 'remove directory' for cleaning up daily builds

For deleting a directory from a filesystem, rm is your fastest option. On linux, sometimes we do our builds (few GB) in a ramdisk, and it has a really impressive delete speed :) You could also try different filesystems, but on AIX/Solaris you may not have many options...

If your goal is to have the directory $dir empty now, you can rename it, and delete it later from a background/cron job:

mv "$dir" "$dir.old"
mkdir "$dir"
# later
rm -r -f "$dir.old"

Another trick is that you create a seperate filesystem for $dir, and when you want to delete it, you just simply re-create the filesystem. Something like this:

# initialization
mkfs.something /dev/device
mount /dev/device "$dir"


# when you want to delete it:
umount "$dir"
# re-init
mkfs.something /dev/device
mount /dev/device "$dir"

I forgot the source of this trick but it works:

EMPTYDIR=$(mktemp -d)
rsync -r --delete $EMPTYDIR/ dir_to_be_emptied/