fincore
page cache inspector for files
TLDR
Show how much of a file is resident in the page cache
$ fincore [path/to/file]
Check several files at once$ fincore [path/to/file1] [path/to/file2]
Show every column available$ fincore --output-all [path/to/file]
Choose the columns yourself$ fincore --output PAGES,SIZE,FILE [path/to/file]
Print exact byte counts rather than human-readable sizes$ fincore --bytes [path/to/file]
Emit JSON$ fincore --json [path/to/file]
Drop the header, which a script does not want$ fincore --noheadings --output RES,FILE [path/to/file]
Check everything in a directory$ fincore [path/to/directory]/*
SYNOPSIS
fincore [options] files
DESCRIPTION
fincore displays how much of a file is currently cached in memory by the kernel's page cache. It shows the number of pages and bytes cached.Useful for understanding memory usage and cache behavior.
PARAMETERS
-n, --noheadings
Do not print a header line.-b, --bytes
Print sizes in bytes (not human-readable units).-c, --total
Print a grand total of results.-o, --output list
Specify output columns (use +list to extend defaults).--output-all
Show all available columns.-r, --raw
Produce output in raw format.-J, --json
Use JSON output format.-R, --recursive
Recurse into directories.-h, --help
Display help.-V, --version
Print version.
INSTALL
sudo apt install util-linux-extra
sudo apk add util-linux-misc
CAVEATS
Part of util-linux. Shows point-in-time snapshot of cache state. Cache contents change dynamically based on system activity.
