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

by on January 4, 2006 · 15 comments· LAST UPDATED January 20, 2011

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I'd like to find out how long the system has been running under UNIX or Linux operating system. How do I find out system uptime?

Both Linux and UNIX like systems comes 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, information from /proc or utmp file is not directly readable by humans so you need to use the following commands.

UNIX / Linux uptime command

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

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

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

$ top
Sample outputs:

Fig.01: UNIX uptime top command output

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.

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{ 15 comments… read them below or add one }

1 Onur Buyukceran July 22, 2007 at 1:39 am

my favorite :) updates every second….

top -d 1

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2 Benjamin Alawani August 26, 2009 at 9:30 am

Nice looking site; useful and clear information. Good job!

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3 Andy Konecny March 10, 2010 at 9:49 pm

The only problem with the uptime command is that it isn’t always obvious what units of measure to the time it has been up. Just a bit confusing for those new to it, especially those from the Windoze world trying to come over to Linux. Just fleshing out the units (up 5 hours:54 minutes (days:hours:minutes)) on this would certainly help in bringing more over, especially if we can get into the man&info pages.

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4 Mohamed November 28, 2010 at 4:57 am

$ uptime
07:55:56 up 3 days, 17:37, 6 users, load average: 0.04, 0.06, 0.01
$

by default it will give how many days the OS is up, and how many hours:mins.
if it less than 1 day, it will give only hours:mins.

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5 Anwar December 3, 2010 at 8:33 am

Wonderful.

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6 Ravi May 10, 2011 at 1:24 pm

Hi,

How do I get only time information excluding other load information

Thanks,
Ravi.

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7 joe April 19, 2012 at 6:18 pm

How do I get only time information excluding other load information

# 1. run Command
# 2. strip unneeded leading data
# 3. check if the uptime is greater than 24 hours
# 4. make the output human readable
# 5. trim any leading space

uptime | \
sed s/^.*up// | \
awk -F, '{ if ( $3 ~ /user/ ) { print $1 $2 } else { print $1 }}' | \
sed -e 's/:/\ hours\ /' -e 's/ min//' -e 's/$/\ minutes/' | \
sed 's/^ *//'

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8 Igor September 3, 2012 at 9:37 am

For people who want to get uptime within a C program I would suggest having a look at sysinfo() too…

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9 mk March 15, 2013 at 8:56 pm

nice and so useful
thank you

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10 Brookly April 3, 2013 at 3:16 pm

How can i know uptime of a server machine without logging in it ?? Is there any way?

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11 kunal July 15, 2013 at 1:47 pm

Hello Buddies , plz specify whats the value ‘4:29′ in the above output.

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12 Pradeep January 27, 2014 at 1:02 pm

@Kunal It’s 4 hours and 29mins. So from the output the server uptime is 13 days, 4 hours and 31 mins.

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13 Viet August 13, 2014 at 12:02 am

thanks for this!

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14 Jim November 17, 2014 at 3:54 pm

Did you see the output within one hour of startup? Is it, e.g. 0:15, :15 or 15 for the 15 minutes after startup?

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15 davux February 2, 2015 at 7:55 pm

On most systems you can do cat /proc/uptime if you’re only interested in the uptime. The first number is how many seconds the system has been up for, and the second number is how many seconds it’s spent idle.

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