View and clear Ubuntu system cache (qbit)

foreword

• This article was tested under Ubuntu 20.04

View cache

fincore

• See how big a single file is in the cache

   fincore filename

• Check how big all files in the directory are in the cache

   ls ./ | xargs fincore

• Recursively view the cache of all files in a directory

   find ./ -type f | xargs fincore

vmtouch

• See how big a single file is in the cache

   vmtouch filename

• Check how big all files in the directory are in the cache

   vmtouch ./

pcstat

• Not tried, https://github.com/tobert/pcstat

hcache

• Not tried, https://github.com/silenceshell/hcache

This article is from qbit snap

Empty the cache

Just empty the PageCache

 sync; echo 1 > /proc/sys/vm/drop_caches

Empty only dentries and inodes

 sync; echo 2 > /proc/sys/vm/drop_caches

Also empty PageCache, dentries and inodes.

 sync; echo 3 > /proc/sys/vm/drop_caches

This article is from qbit snap