Tail Dmesg - Linux Forums

06-28-2005	#1 (permalink)
Slip Linux User Join Date: Nov 2003 Location: Brooklyn, NY Posts: 347	Tail Dmesg Anyone know of a way to tail -f dmesg?

06-28-2005	#2 (permalink)
anomie Linux Guru Join Date: Mar 2005 Location: Texas Posts: 1,696	Are you asking what the file name is of the ring buffer? The only time that I know of that it gets written to is during boot time. (But I could be mistaken.) What would be the purpose of putting tail -f on it? Just curious.

06-28-2005

#3 (permalink)

Slip

Linux User

Join Date: Nov 2003

Location: Brooklyn, NY

Posts: 347

Quote:

Originally Posted by anomie

Are you asking what the file name is of the ring buffer? The only time that I know of that it gets written to is during boot time. (But I could be mistaken.) What would be the purpose of putting tail -f on it? Just curious.

tail -f <logfile>
Would display the last few lines of the logfile as it keeps getting updated without having to run tail or cat again. Try it.

I am trying to have dmesg displayed in the terminal and keep getting updated without me having to do anything.

06-28-2005	#4 (permalink)
bigtomrodney /etc/init.d/moderator Join Date: Nov 2004 Location: Sunny South-East of Ireland Posts: 6,104	Try Code: dmesg \| tail for static, I haven't got tailf here at the moment so I can't check - but you could always script something like Code: #!/bin/bash while true do dmesg \| tail sleep 3 done That's just off the top of my head, you may tweak away. I'll let youhave that under the GPL !! haha __________________ Registered Linux user #378740 New members read here / Forum Rules #linuxforums on irc.freenode.net

06-28-2005

#5 (permalink)

Slip

Linux User

Join Date: Nov 2003

Location: Brooklyn, NY

Posts: 347

Quote:

Originally Posted by bigtomrodney

Try

Code:

dmesg | tail

for static, I haven't got tailf here at the moment so I can't check - but you could always script something like

Code:

#!/bin/bash
while true
do dmesg | tail 
sleep 3
done

That's just off the top of my head, you may tweak away. I'll let youhave that under the GPL !! haha

Yeah, I have tried

Code:

dmesg | tail

but it does not want to accept -f.

06-28-2005

#6 (permalink)

anomie

Linux Guru

Join Date: Mar 2005

Location: Texas

Posts: 1,696

Quote:

tail -f <logfile>
Would display the last few lines of the logfile as it keeps getting updated without having to run tail or cat again. Try it.

I know that, but I am asking what the purpose is of tail -f on the ring buffer. It only gets written to during boot time (I think). So you can tail -f on it but nothing will happen.

06-28-2005	#7 (permalink)
anomie Linux Guru Join Date: Mar 2005 Location: Texas Posts: 1,696	The ring buffer in FC should be /var/log/dmesg. Not sure what it is in other distros. You have to tail that, not the dmesg command. (And as I said, I don't think you will be seeing anything change with it unless you are booting.)

06-28-2005	#8 (permalink)
anomie Linux Guru Join Date: Mar 2005 Location: Texas Posts: 1,696	It's interesting - under SuSE the ring buffer appears to be made up of two files. /var/log/messages /var/log/warn However, it is not all the lines in those files; it is only the kernel messages. So when dmesg gives results under SuSE it appears to contain those found in the two files with the prefix 'kernel:'. Your distro may be totally different.

06-29-2005	#9 (permalink)
bigtomrodney /etc/init.d/moderator Join Date: Nov 2004 Location: Sunny South-East of Ireland Posts: 6,104	dmesg also reports any devices plugged in or out, as mentioned it is kernel messages. trying plugging in a flash drive, and run it before and after. __________________ Registered Linux user #378740 New members read here / Forum Rules #linuxforums on irc.freenode.net

09-24-2009	#10 (permalink)
axelabs Just Joined! Join Date: Sep 2009 Posts: 1	This is how I do it... Code: while true;do sudo dmesg -c;done Keep in mind that the '-c' flag clears the message buffer into stdout. The 'sudo' is unnecessary if you are root. If you feel this is eating too much of your CPU resource, try adding a 'sleep 1' before the loop is done.

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