Quickly check how long a Linux host has been running and how busy it is. 16.11.2025 | reading time: 3 min Want to know how long a machine has been running and whether it is overloaded Right away get the uptime and load averages from small commands that reveal boot time and recent system demand. Run this demo Try these commands and read the output exactly as shown then compare the numbers to your CPU count for context. ``` $ uptime 10:23:45 up 5 days, 3:12, 2 users, load average: 0.42, 0.37, 0.31 ``` ``` $ cat /proc/loadavg 0.42 0.37 0.31 1/234 5678 ``` The first line shows current time, uptime span, logged in users and three load averages for 1, 5 and 15 minutes; the second shows the same three numbers plus scheduler info. What those numbers mean Interpret the three load numbers as averages of runnable and uninterruptible processes over 1, 5 and 15 minutes and compare them to the number of CPU cores: a load of 4 on a 4‑core machine implies full CPU saturation while 4 on a single core means heavy overload; note that load includes processes waiting in uninterruptible sleep such as disk I/O waits so high load may be I/O bound rather than CPU bound. Useful flags and quick checks Use `uptime -p` for a human friendly uptime and `uptime -s` to see the boot timestamp, use `w` to view load plus who is logged in and what they run, and read `cat /proc/loadavg` when scripting; when load looks high list top CPU consumers with `top` or `ps aux --sort=-%cpu` and check disk activity with `iostat` and `iotop` to separate CPU from I/O problems. When to dig deeper If sustained 15‑minute load exceeds CPU count take these steps: identify culprit processes, inspect I/O wait and disk queues, verify memory pressure and swapping, and check for runaway tasks; logging these checks helps spot patterns before users complain. Keep learning Mastering uptime and load averages is a first step toward capacity planning and troubleshooting; pursue deeper skills in process accounting, performance tools and system internals and consider formal certification to structure learning. bitsandbytes.academy offers intensive exam preparation for CompTIA Linux+ and LPIC-1 if the reader wants to certify. Join Bits & Bytes Academy First class LINUX exam preparation. processes utilities troubleshooting boot-process
