Sponsored Content
Operating Systems Linux Red Hat Difference between uptime and who -b Post 302950351 by agent.kgb on Thursday 23rd of July 2015 04:43:27 PM
Old 07-23-2015
Linux uptime command looks at file /proc/uptime and last reboot shows the reboot entry from /var/log/wtmp. The reboot entry is placed (I suppose) by init command and /proc/uptime shows uptime from the kernel's point of view - from starting the 1st CPU. Nobody knows your system better then you, but I would trust the output of uptime. wtmp file is easy to manipulate and it starts on the same date, as it shows last reboot. It may be, that last doesn't find any reboot entries at all and just reports the first entry of the file as last reboot time.
This User Gave Thanks to agent.kgb For This Post:
 

10 More Discussions You Might Find Interesting

1. UNIX for Dummies Questions & Answers

uptime

Hi Folks uptime 12:24pm up 2 days, 3:12, 4 users, load average: 0.00, 0.00, 0.00 what does the load average figure mean.. regards Hrishy (2 Replies)
Discussion started by: xiamin
2 Replies

2. UNIX for Dummies Questions & Answers

Getting uptime

I'm trying to get the uptime of my computer (Mac OS X) and I can go into the terminal and type "uptime" OK, and that gives me a string with the uptime in it. The problem is that the string changes a lot, and its very difficult to get the data I'm trying to extract out cleanly. Now I have 3... (2 Replies)
Discussion started by: Freefall
2 Replies

3. UNIX for Dummies Questions & Answers

uptime

On HP-UX, the 13th argument of uptime is sometime the load and sometime the word AVERAGE:??? 14 Jun 06 5:00pm up 44 days, 54 mins, 0 users, load average: 0.00, 0.02, 0.03 14 Jun 06 5:15pm up 44 days, 1:09, 0 users, load average: 0.00, 0.01, 0.01 When the time is in minutes, then the load... (1 Reply)
Discussion started by: qfwfq
1 Replies

4. UNIX for Dummies Questions & Answers

Uptime

hello folks! how can I display just the uptime without the current time, the word "up", and the load averages using the uptime command or some other command I do not know about? (13 Replies)
Discussion started by: MastaFue
13 Replies

5. Shell Programming and Scripting

Process Uptime

Hi, I need some help about a script i need to write. I want to check , if some specific process, are running since 2 hours. I tried to use a loop , grep my pid and use find -ctime on /proc directory, to list what i need. for i in `ps -ef |grep process |grep -v grep|awk '{print $2}'`... (2 Replies)
Discussion started by: rokerij
2 Replies

6. UNIX for Advanced & Expert Users

We have uptime but is there a starttime?

Hi gurus, Is it possible to get the time on when the server was re-started or does the output from who -b is the answer to my question? UNIX flavour is Solaris. The uptime command gives information on how long the server has been up but I want to know when the server was started. The output... (4 Replies)
Discussion started by: newbie_01
4 Replies

7. UNIX for Dummies Questions & Answers

Difference between system uptime and last boot time.

My Linux system was last rebooted few hours ago. But it seems little confusing for me to figure out the exact reason behind it. I guess following command should justify what i meant to say. # date Wed May 11 13:22:49 IST 2011 # last | grep "May 10" reboot system boot 2.6.18-194.el5 ... (5 Replies)
Discussion started by: pinga123
5 Replies

8. Shell Programming and Scripting

Extract the uptime from the output of the uptime command

Hi! I want to extract the uptime from the output of the uptime command. The output: 11:53 up 3:02, 2 users, load averages: 0,32 0,34 0,43 I just need the "3:02" part. How can I do this? Dirk (6 Replies)
Discussion started by: Dirk Einecke
6 Replies

9. Shell Programming and Scripting

Uptime script

How to write a shell script which can generate server uptime report from the UNIX servers? (3 Replies)
Discussion started by: paventhan
3 Replies

10. War Stories

Once upon an uptime.

Hi All, Having recently started a new job, a Data Center Migration in fact I have been tasked with looking at some of the older Solaris boxes when I came across this little gem. nismas# uname -a SunOS nismas 5.5.1 Generic_103640-27 sun4u sparc SUNW,Ultra-1 nismas# uptime 10:37am up 2900... (2 Replies)
Discussion started by: gull04
2 Replies
HALT(8) 						Linux System Administrator's Manual						   HALT(8)

NAME
halt, reboot, poweroff - stop the system. SYNOPSIS
/sbin/halt [-n] [-w] [-d] [-f] [-i] [-p] [-h] /sbin/reboot [-n] [-w] [-d] [-f] [-i] /sbin/poweroff [-n] [-w] [-d] [-f] [-i] [-h] DESCRIPTION
halt notes that the system is being brought down in the file /var/log/wtmp, and then either tells the kernel to halt, reboot or power-off the system. If halt or reboot is called when the system is not in runlevel 0 or 6, in other words when it's running normally, shutdown will be invoked instead (with the -h or -r flag). For more info see the shutdown(8) manpage. The rest of this manpage describes the behaviour in runlevels 0 and 6, that is when the systems shutdown scripts are being run. OPTIONS
-n Don't sync before reboot or halt. Note that the kernel and storage drivers may still sync. This implies -d. -w Don't actually reboot or halt but only write the wtmp record (in the /var/log/wtmp file). -d Don't write the wtmp record. -f Force halt or reboot, don't call shutdown(8). -i Shut down all network interfaces just before halt or reboot. -h Put all hard drives on the system in stand-by mode just before halt or power-off. -p When halting the system, switch off the power. This is the default when halt is called as poweroff. DIAGNOSTICS
If you're not the superuser, you will get the message `must be superuser'. NOTES
Under older sysvinit releases , reboot and halt should never be called directly. From release 2.74 on halt and reboot invoke shutdown(8) if the system is not in runlevel 0 or 6. This means that if halt or reboot cannot find out the current runlevel (for example, when /var/run/utmp hasn't been initialized correctly) shutdown will be called, which might not be what you want. Use the -f flag if you want to do a hard halt or reboot. The -h flag puts all hard disks in standby mode just before halt or power-off. Right now this is only implemented for IDE drives. A side effect of putting the drive in stand-by mode is that the write cache on the disk is flushed. This is important for IDE drives, since the kernel doesn't flush the write cache itself before power-off. The halt program uses /proc/ide/hd* to find all IDE disk devices, which means that /proc needs to be mounted when halt or poweroff is called or the -h switch will do nothing. AUTHOR
Miquel van Smoorenburg, miquels@cistron.nl SEE ALSO
shutdown(8), init(8) Nov 6, 2001 HALT(8)
All times are GMT -4. The time now is 09:41 PM.
Unix & Linux Forums Content Copyright 1993-2022. All Rights Reserved.
Privacy Policy