Dynamic MOTD on Alpine Linux
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When we sign in to our server, the message of the day (MOTD) is pretty lame. Let's get something better!
This is the default MOTD of alpine:
Welcome to Alpine!
The Alpine Wiki contains a large amount of how-to guides and general
information about administrating Alpine systems.
See <http://wiki.alpinelinux.org>.
You can setup the system with the command: setup-alpine
You may change this message by editing /etc/motd.
And here's my new MOTD. I even show the WireGuard ip address:
Name: intra.philt3r
Kernel: 6.1.35-0-lts
Distro: Alpine Linux v3.18
Version 3.18.2
Uptime: 0 days, 0 hours, 22 minutes
CPU Load: 0.00, 0.00, 0.00
Memory: 468M
Free Memory: 217M
Disk: 6.6G
Free Disk: 6.6G
eth0 Address: 192.168.1.71
wg0 Address: 10.131.111.1
Start and enable cron at startup (it should be installed by default):
rc-service crond start
rc-update add crond
Let's run a script every 15 minutes to update the /etc/motd file:
/etc/periodic/15min/motd
Here's the content of my MOTD:
#!/bin/sh
#. /etc/os-release
PRETTY_NAME=`awk -F= '$1=="PRETTY_NAME" { print $2 ;}' /etc/os-release | tr -d '"'`
VERSION_ID=`awk -F= '$1=="VERSION_ID" { print $2 ;}' /etc/os-release`
UPTIME_DAYS=$(expr `cat /proc/uptime | cut -d '.' -f1` % 31556926 / 86400)
UPTIME_HOURS=$(expr `cat /proc/uptime | cut -d '.' -f1` % 31556926 % 86400 / 3600)
UPTIME_MINUTES=$(expr `cat /proc/uptime | cut -d '.' -f1` % 31556926 % 86400 % 3600 / 60)
cat > /etc/motd << EOF
Name: `hostname`
Kernel: `uname -r`
Distro: $PRETTY_NAME
Version $VERSION_ID
Uptime: $UPTIME_DAYS days, $UPTIME_HOURS hours, $UPTIME_MINUTES minutes
CPU Load: `cat /proc/loadavg | awk '{print $1 ", " $2 ", " $3}'`
Memory: `free -m | head -n 2 | tail -n 1 | awk {'print $2'}`M
Free Memory: `free -m | head -n 2 | tail -n 1 | awk {'print $4'}`M
Disk: `df -h / | awk '{ a = $2 } END { print a }'`
Free Disk: `df -h / | awk '{ a = $2 } END { print a }'`
eth0 Address: `ifconfig eth0 | grep "inet addr" | awk -F: '{print $2}' | awk '{print $1}'`
wg0 Address: `ifconfig wg0 | grep "inet addr" | awk -F: '{print $2}' | awk '{print $1}'`
EOF
Make the script executable, and check if it's good:
chmod a+x /etc/periodic/15min/motd
run-parts --test /etc/periodic/15min
If you're lazy and don't want to wait 15 minutes, run the script directly:
/etc/periodic/15min/motd
Log out and log back in, you should see the new MOTD!
Resources
https://kingtam.win/archives/apline-custom.html
I just copy/pasted and changed the MOTD.