Investigate linux filesystem cache usage

cached_by_extension.sh

#!/bin/bash

dir=$1
if [ "$1" == "" ]; then
    echo "Must provide a directory as an argument"
    exit 1
fi

ftypes=$(find $1 -type f -size +10c | grep -E ".*\.[a-zA-Z0-9]*$" | sed -e 's/.*\(\.[a-zA-Z0-9]*\)$/\1/' | sort | uniq)

for ft in $ftypes
do
    echo -n "$ft "
    ./pcstat --terse `find $1 -name "*${ft}" -type f -size +10c` | awk -F"," '/^\// { s+=$2; t+=$5; c+=$6 }END{print s " " 100*c/t}'
done

echo -n "* "
./pcstat --terse `find $1 -type f -size +10c` | awk -F"," '/^\// { s+=$2; t+=$5; c+=$6 }END{print s " " 100*c/t}'

gistfile1.sh

# Requires https://code.google.com/p/linux-ftools/

# suggest that linux cache somedir in memory
find -L <somedir> -type f -exec linux-fadvise {} POSIX_FADV_WILLNEED \;

# check what percentage of somedir is cached in memory
linux-fincore -s $(find -L /mnt/<somedir> -type f) | awk '/^\/mnt/ { t+=$2; c+=$6 }END{print 100*c/t}'

# Sinc linux-ftools seems to be abandonded and not in modern ubuntu, maybe try this tool?
https://github.com/tobert/pcstat
curl -L -o pcstat https://github.com/tobert/pcstat/raw/2014-05-02-01/pcstat.x86_64
chmod 755 pcstat
./pcstat --terse `find /mnt/<somedir> -type f -size +10c` | awk -F"," '/^\/mnt/ { t+=$5; c+=$6 }END{print 100*c/t}'