Quick, practical commands to find how long a Linux host has been running and what the numbers mean. 16.11.2025 | reading time: 2 min Need to know how long a server has been running? Use a handful of commands to get boot time, runtime in seconds, user sessions and load averages in seconds; the examples below show exactly what to run and why. Quick check Hands-on case: on a Linux box run the following to get a fast picture of uptime and boot time: ``` $ uptime 08:36:01 up 10 days, 3:12, 2 users, load average: 0.15, 0.05, 0.01 $ who -b system boot 2025-11-06 05:24 $ cat /proc/uptime 864000.00 432000.00 ``` The first line shows human-friendly uptime and load averages, `who -b` prints the boot timestamp, and `/proc/uptime` gives raw seconds since boot followed by accumulated idle seconds. What the numbers mean The `uptime` line bundles three things: a human-readable uptime, number of logged-in users and three load averages; load averages are the average runnable tasks over 1, 5 and 15 minutes, not CPU percentages; `/proc/uptime` first field is seconds since boot (convert by dividing by 86400 for days) and the second field is total idle time across CPUs. Practical use cases Check uptime before applying kernel updates or scheduling reboots, correlate long uptimes with creeping memory or process leaks, verify that a monitored server actually restarted after maintenance, and use uptime metrics when diagnosing performance regressions tied to load averages. Related commands at a glance Complement `uptime` with `w` to see who is logged in and what they run, `last reboot` to list historical reboots, and `systemctl status` or `journalctl` to investigate why a system booted or failed; these combine runtime data with event context for troubleshooting. Final note A quick uptime check can prevent guessing and speed troubleshooting; keep practicing these commands and learn to script their output for monitoring pipelines — consider deepening skills with CompTIA Linux+ or LPIC-1 exam preparation at bitsandbytes.academy for a structured path. Join Bits & Bytes Academy First class LINUX exam preparation. utilities boot-process troubleshooting processes
