MAC OS

# Update brew to the latest version with
$ brew update

# Check your system health with, and fix any missing links
$ brew doctor

# Upgrade all of your brew packages
$ brew upgrade
$ pdffonts main.pdf

Ubuntu

lsb_release -a
kern.log - 5GB
messages - 1.9GB
syslog - 2.9GB
syslog.1 - 1.3GB