Thursday 4 September 2008 — This is close to 15 years old. Be careful.
My laptop has a 100Gb drive, and recently it was 98% or so full! As part of the job of cleaning it up, I used SpaceMonger to see where it the space was going. I noticed a few largish directories whose names indicated they were caches of some sort, and wondered how much disk was being lost to copies of files that I didn’t really need to keep around.
I cobbled together this Python script to recursively list the size of folders and files, but only if they exceed specified minimums:
""" List file sizes recursively, but only if they exceed
import stat, os
# Minimum size for a file or directory to be listed.
min_file = 10000000
min_dir = 1000000
format = "%15d %s"
dir_format = "%15d / %s"
err_format = " !!! ! %s"
""" Process a single directory, return its total size,
and print intermediate results along the way.
files = os.listdir(d)
except Exception, e:
print err_format % str(e)
total = 0
for f in files:
f = os.path.join(d, f)
st = os.stat(f)
size = st[stat.ST_SIZE]
is_dir = stat.S_ISDIR(st[stat.ST_MODE])
size = do_dir(f)
if size >= min_file:
print format % (size, f)
total += size
if total >= min_dir:
print dir_format % (total, d)
if __name__ == '__main__':
Running this on my disk, and grep’ing for “cache”, I came up with this list of cache directories:
77428736 / .\Documents and Settings\All Users\Application Data\Apple\Installer Cache
193088296 / .\Documents and Settings\All Users\Application Data\Apple Computer\Installer Cache
127431856 / .\Documents and Settings\All Users\Application Data\Symantec\Cached Installs
1283586 / .\Documents and Settings\All Users\DRM\Cache
8904444 / .\Documents and Settings\batcheln\Application Data\Adobe\CameraRaw\Cache
3109555 / .\Documents and Settings\batcheln\Application Data\Dropbox\cache
9141658 / .\Documents and Settings\batcheln\Application Data\Microsoft\CryptnetUrlCache
6639905 / .\Documents and Settings\batcheln\Application Data\Sun\Java\Deployment\cache
244047364 / .\Documents and Settings\batcheln\Local Settings\Application Data\Adobe\CameraRaw\Cache
35706839 / .\Documents and Settings\batcheln\Local Settings\Application Data\Mozilla\Firefox\Profiles\0ou4abpz.default\Cache
1559441 / .\Documents and Settings\batcheln\Local Settings\Application Data\johnsadventures.com\Background Switcher\FolderQuarterScreenCache
381984768 .\Documents and Settings\batcheln\My Documents\My Pictures\Lightroom\Lightroom Catalog Previews.lrdata\thumbnail-cache.db
44671279 / .\Program Files\Adobe\Adobe Help Center\AdobeHelpData\Cache
1093120 / .\Program Files\Common Files\Microsoft Shared\SFPCA Cache
1139888470 / .\Program Files\Cyan Worlds\Myst Uru Complete Chronicles\sfx\streamingCache
73237698 / .\Program Files\Hewlett-Packard\PC COE 3\OV CMS\Lib\Cache
46559334 / .\WINDOWS\assembly\GAC
20606686 / .\WINDOWS\assembly\GAC_32
55143608 / .\WINDOWS\assembly\GAC_MSIL
105975390 / .\WINDOWS\Driver Cache
96353450 / .\WINDOWS\Installer\$PatchCache$
1898024 / .\WINDOWS\SchCache
1174871 / .\WINDOWS\pchealth\helpctr\OfflineCache
451465998 / .\WINDOWS\system32\dllcache
(I also included the GAC directories: .net Global Assembly Caches). Summing these sizes, I see that 3 Gb or so of space is occupied by self-declared caches. For many of these I don’t know whether it is safe to delete them. Luckily the largest was a game I installed for Max and could completely uninstall.
Windows provides the Disk Cleanup utility, which knows how to get rid of a bunch of stuff you don’t really need. Application developers can even write a handler to clean up their own unneeded files, but it seems application developers don’t, as I don’t have any custom handlers on my machine.
CCleaner is a Windows utility to scrub a little harder at your disk, but even it missed some of these folders: for example, it removed the smaller of the CameraRaw caches (8 Mb), but left the larger (244 Mb). I read online that CameraRaw really doesn’t need those files, so I removed them by hand.
I’m all for applications making use of disk space to improve the user experience, but they should do it responsibly: give me a way to see what’s being used, and give me a way to get it back. And only keep what makes sense: why do my Apple Installer Cache directories have kits for three different versions each of iTunes, QuickTime, and Safari, and seven kits for Apple Mobile Device Support? Why do I need to keep installers for versions that have already been superceded?
$sudo apt-get install filelight
Filelight provides a quick graphical view of where you space is actually used. Pretty pictures.
One bugfix, though: On systems with symlinks, os.stat can throw a file-not-found OSError for a filename you got back from os.listdir.
I stuck in a try:except:pass block and the script worked fine. (This'd also help protect against the case of a file disappearing between when you listdir it and when you stat it)
I've been very happy with WinDirStat, Disk Inventory X (OS X).
And when I wrote the post, I hesitated a moment, thinking, "is this the best way to write this script, because I don't want to put it up there if it's lame in some way." And then I figured it was tangential to the real point, and useful even if boneheaded (it did solve my problem after all), so I posted it anyway. Damn the torpedoes!
That's a sad state of affairs, anything in a folder marked as cache should be regenerated as needed in the normal operation of the software, so it should always be safe to delete. Is this not true? Is this one of those "my programmer's 6th sense says warning" situations, or have you been burned by deleting a cache folder before?
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