Linux Server Uptime Command To Find Out How Long The System Has Been Running

I would like to find out how long the system has been running under a UNIX or Linux operating system. How do I find out system uptime? How to tell how long the Linux system has been running on?

Both Linux and Unix-like systems come with various command to find out server uptime command. Under Linux file /proc/uptime has uptime information and file/var/run/utmp has information about who is currently logged on. However, info from /proc/uptime or utmp file is not directly readable by humans; therefore, you need to use the following commands. This page shows command that tell how long the Linux and Unix-based system has been running.

Linux Server Uptime Command

Open a command-line terminal (select Applications > Accessories > Terminal), and then type the following command:
$ uptime
Sample outputs:

 21:54:11 up 13 days,  4:29,  1 user,  load average: 0.21, 0.21, 0.12

The uptime command gives a one line display of the following information.

  • The current time (21:54:11)
  • How long the system has been running (up 13 days)
  • How many users are currently logged on (1 user)
  • The system load averages for the past 1, 5, and 15 minutes (0.21, 0.21, 0.12)

See uptime in pretty format pass the -p option to the uptime command

$ uptime -p
Sample outputs:

up 3 days, 2 hours, 11 minutes

This is the same information contained in the header line displayed by the w command and top command:
$ w
Sample outputs:

 21:56:06 up 13 days,  4:31,  1 user,  load average: 0.03, 0.14, 0.09
USER     TTY      FROM              [email protected]   IDLE   JCPU   PCPU WHAT
root     pts/0    123.xxx.yy.zzz    21:54    0.00s  0.02s  0.00s vi

Getting help about uptime command

To check system uptime in Linux and Unix we use the uptime command. However, if you need more information on command option type the following man command:
$ man uptime
OR
$ uptime --help
Sample outputs:

 -p, --pretty   show uptime in pretty format
 -h, --help     display this help and exit
 -s, --since    system up since
 -V, --version  output version information and exit

Use top command to display Linux system uptime

Type the following command:
$ top
Sample outputs:

Fig.01: UNIX uptime top command output

Please note that the w command displays who is logged on and what they are doing while top command provides a dynamic real-time view of a running Linux/UNIX/BSD operating systems including processes.

Conclusion

In this quick tutorial, you learned how to use uptime, w, and top commands to see system uptime and other information from the command line.

Posted by: SXI ADMIN

The author is the creator of SXI LLC and a seasoned sysadmin, DevOps engineer, and a trainer for the Linux operating system/Unix shell scripting. Get the latest tutorials on SysAdmin, Linux/Unix and open source topics via RSS/XML feed or weekly email newsletter.