Now, it is time to have some blinking lights and fun settings, but useful nevertheless ! A dynamic status message of the day with server health information. I like to have a summary of what is the health of the server, what needs to be done, pending upgrades… immediately when I connect. Furthermore, it is very useful if you need to share a screenshot with someone else.

Tooling

I like these useless banners, there are a lot of choices : figlet, toilet, cowsay … and the old banner. I will also need lsb-tools to fetch the linux distribution details.

apt-get install -y figlet toilet lsb-release

Header with hostname and release

First part is to generate a banner with the hostname to avoid any mistake on the server, and to display the current Linux distribution details.

e107a95e5127814353389c579d0c0e39.png

cat << EOF > /etc/update-motd.d/00-header
#!/bin/sh
[ -r /etc/lsb-release ] && . /etc/lsb-release
if [ -z "\$DISTRIB_DESCRIPTION" ] && [ -x /usr/bin/lsb_release ]; then
    # Fall back to using the very slow lsb_release utility
    DISTRIB_DESCRIPTION=\$(lsb_release -s -d)
fi
figlet -f pagga -w 100 \$(hostname)
printf "\n"
printf "Welcome to %s.\n" "\$DISTRIB_DESCRIPTION"
uname -snrvm
printf "\n"
EOF
chmod +x /etc/update-motd.d/00-header
rm /etc/update-motd.d/10-uname

System health informations

Then, I like to have the date and time, the load average, the memory and swap usage and a summary of the running processes.

8d4bd5941bd8028a64a69d5c3f01710f.png

cat << EOF > /etc/update-motd.d/10-sysinfo
#!/bin/sh
date=\`date\`
load=\`cat /proc/loadavg | awk '{print \$1}'\`
root_usage=\`df -h / | awk '/\\// {print \$(NF-1)}'\`
memory_usage=\`free -m | awk '/Mem:/ { total=\$2 } /buffers\\/cache/ { used=\$3 } END { printf("%3.1f%%", used/total*100)}'\`
swap_usage=\`free -m | awk '/Swap/ { printf("%3.1f%%", "exit !\$2;\$3/\$2*100") }'\`
users=\`users | wc -w\`
time=\`uptime | grep -ohe 'up .*' | sed 's/,/\\ hours/g' | awk '{ printf \$2" "\$3 }'\`
processes=\`ps aux | wc -l\`
ip=\`ip addr | grep inet.*enp | sed 's/.*inet //;s/\\/.*//' | head -n1\`
echo "System information as of: \$date"
echo
printf "System load:\t%s\tIP Address #1:\t%s\n" \$load \$ip
printf "Memory usage:\t%s\tSystem uptime:\t%s\n" \$memory_usage "\$time"
printf "Usage on /:\t%s\tSwap usage:\t%s\n" \$root_usage \$swap_usage
printf "Local Users:\t%s\tProcesses:\t%s\n" \$users \$processes
echo
EOF
chmod +x /etc/update-motd.d/10-sysinfo

Available system upgrades

Finally, I generate a list of the packages that need to be upgraded and I empty the default /etc/motd static file. Side effect : this part introduce a few seconds latency at each connection. This is mostly due to the apt invocation.

628ab45e850f21d64f6aa2b798508d0a.png

cat << EOF > /etc/update-motd.d/20-upgrades
#!/bin/sh
number=\`apt list --upgradable 2> /dev/null | grep 'upgradable' | wc -l\`
printf "Available updates : %s\\n" \$number
if [ \$number -gt 0 ]; then
    printf "\\033[1;31mSystem needs %s updates\\033[0m\\n" \$number
    apt list --upgradable 2> /dev/null | grep 'upgradable'
else
    printf "\\033[1;32mSystem is uptodate\\033[0m\\n"
fi
echo
EOF
chmod +x /etc/update-motd.d/20-upgrades
echo > /etc/motd

Materials and Links

How to setup dynamic motd for Debian Jessie by thesysad 1

Footnotes

  1. http://www.thesysad.com/blog/how-to-setup-dynamic-motd-for-debian-jessie/ ↩