#
# ручной ввод
#

mkdir /dev/shm/Cache
rsync -avzP --numeric-ids /home/teatest/.cache/google-chrome/Default/Cache/ /dev/shm/Cache/
rm -r /home/teatest/.cache/google-chrome/Default/Cache
ln -s /dev/shm/Cache  /home/teatest/.cache/google-chrome/Default/Cache
sudo touch /usr/bin/google-chrome-cache-start.sh

#
# содержимое google-chrome-cache-start.sh
#

#!/bin/bash
startup () {
mkdir /dev/shm/Cache
rsync -avzP --numeric-ids /home/teatest/.cache/google-chrome/Default/Cache2/ /dev/shm/Cache/
}

sync () {
rsync -avzP --numeric-ids /dev/shm/Cache/ /home/teatest/.cache/google-chrome/Default/Cache2/
}

$1

#
# crontab -e
#

@reboot /usr/bin/google-chrome-cache-start.sh startup
*/30 * * * *  /usr/bin/google-chrome-cache-start.sh sync

#
# syslog
#

cron[929]: (CRON) INFO (pidfile fd = 3)
cron[1008]: (CRON) STARTUP (fork ok)
cron[1008]: (CRON) INFO (Running @reboot jobs)
CRON[1053]: (teatest) CMD (/usr/bin/google-chrome-cache-start.sh startup)
CRON[1045]: (CRON) info (No MTA installed, discarding output)