pam_motd¶

When logging into an Ubuntu server you may have noticed the informative Message Of The Day (MOTD).

Packages adding to MOTD¶

There are various packages that add to the MOTD by placing configuration in /etc/update-motd.d/.

Landscape-sysinfo¶

Here is one example of system information obtained and displayed by Landscape:

landscape-common: provides the core libraries of landscape-client, which is needed to manage systems with Landscape (proprietary). Yet the package also includes the landscape-sysinfo utility which is responsible for displaying core system data involving CPU, memory, disk space, etc. For instance:
```
System load:             0.0
Usage of /:              25.7% of 8.55GB
Memory usage:            31%
Swap usage:              0%
Processes:               125
Users logged in:         0
IPv4 address for enp5s0: 10.185.198.41
IPv6 address for enp5s0: fd42:50cb:3a48:1f2c:216:3eff:fe27:c18a
```
Note

You can run landscape-sysinfo manually at any time.
update-notifier-common: provides information on available package updates, impending filesystem checks (fsck), and required reboots (e.g.: after a kernel upgrade).

pam_motd executes the scripts in /etc/update-motd.d in order based on the number prepended to the script. The output of the scripts is written to /var/run/motd, keeping the numerical order, then concatenated with /etc/motd.tail.

Other default MOTD entries¶

The default content in /etc/update-motd.d/ in 26.04 covers (most of them only deliver output if there is something meaningful to report):

base-files establishing the basic mechanism: 00-header, 10-help-text, 50-motd-news
base-files also provides Ubuntu news: 50-motd-news
landscape info about the system: 50-landscape-sysinfo
fwupd presents potential firmware updates: 85-fwupd
update-notifier-common reports about available updates: 90-updates-available
ubuntu-pro-client mentions expiring Ubuntu Pro subscriptions: 91-contract-ua-esm-status
ubuntu-release-upgrader-core suggests upgrades: 91-release-upgrade
unattended-upgrades informs if updates could not be installed automatically: 92-unattended-upgrades
update-notifier-common notifies if the HWE kernel might go end of life: 95-hwe-eol
overlayroot reports if any overlays are active: 97-overlayroot
update-notifier-common suggests regular filesystem checks: 98-fsck-at-reboot
update-notifier-common also hints if a reboot is required: 98-reboot-required

Customization¶

You can modify the configuration provided by the system or consider adding your own dynamic information to the MOTD by adding to /etc/update-motd.d/.

This example is not meant to be serious, instead it is a bit of fun to demonstrate the usage of pam_motd for your own messages.

#!/bin/bash

# 1. Get timestamp and calculate nearest sysadminday
NOW=$(date +%s)
THIS_YEAR=$(date +%Y)
TARGET_PREV=$(date -d "$((THIS_YEAR-1))-08-01 last friday" +%s)
TARGET_CURR=$(date -d "$THIS_YEAR-08-01 last friday" +%s)
TARGET_NEXT=$(date -d "$((THIS_YEAR+1))-08-01 last friday" +%s)

# 2. Loop to find the shortest distance
MIN_DIFF=9999999999
CHOSEN_DAYS=0
TIMING=""
for TARGET in $TARGET_PREV $TARGET_CURR $TARGET_NEXT; do
    # Calculate difference
    DIFF=$(( (TARGET - NOW) / 86400 ))

    # Get absolute value for comparison
    if [ $DIFF -lt 0 ]; then
        ABS_DIFF=$((DIFF * -1))
        CURRENT_TIMING="ago"
    else
        ABS_DIFF=$DIFF
        CURRENT_TIMING="in"
    fi

    # Update if this is the closest date found so far
    if [ $ABS_DIFF -lt $MIN_DIFF ]; then
        MIN_DIFF=$ABS_DIFF
        CHOSEN_DAYS=$ABS_DIFF
        TIMING=$CURRENT_TIMING
    fi
done

# 3. Report to gain some admin-love
if [ "$CHOSEN_DAYS" -eq 0 ]; then
    echo -e "System Administrator Appreciation Day is Today! Gifts welcome."
elif [ "$TIMING" == "ago" ]; then
    echo -e "System Administrator Appreciation Day is ${CHOSEN_DAYS} days ago but we'd appreciate to be treated well every day."
else
    echo -e "System Administrator Appreciation Day is in ${CHOSEN_DAYS} days but we'd appreciate to be treated well every day."
fi

Then make it executable

chmod +x /etc/update-motd.d/98-admin-reminder

On next login you should now be greeted with that as part of the message of the day.

$ ssh ubuntu@yoursystem
...
System Administrator Appreciation Day is 181 days ago but we'd appreciate to be treated well every day.

Note

Be careful as this will be executed on every login. The usual pattern to prevent that from slowing down logins is to do anything even slightly complex asynchronously and only cat pre-generated content in the actual MOTD handling. Furthermore consider using stamp files to only update at regular intervals instead of at every login. This example was meant to be kept simple, but the existing serious MOTD entries placed there by the packages make use of such, please look at those for writing your own.

Resources¶

See the update-motd(5) manual page for more options available to update-motd.
The Debian Package of the Day weather article has more details about using the weather utility.