Jamf Pro Computer Extension Attribute for system’s last boot timestamp (UTC)

system-last-boot-timestamp-utc.sh

#!/bin/bash
# 
# Created by jps3@lehigh.edu on 2022-05-17
#
# Jamf Pro > Settings > Computer Management > Extension Attributes
# Display Name      : system-last-boot-timestamp-utc
# Description       : Queries system for timestamp of last boot.
# Data Type         : Date (YYYY-MM-DD hh:mm:ss)
# Inventory Display : Extension Attributes
# Input Type        : Script
# 

LAST_BOOT="$(sysctl -n kern.boottime|sed -E 's/^\{ sec = ([0-9]+),.*$/\1/'|TZ="UTC" xargs date -jf '%s' +"%F %T")"

if [[ -n "$LAST_BOOT" ]]; then
  echo "<result>${LAST_BOOT}</result>"
fi