Tail Dmesg

Anyone know of a way to tail -f dmesg?

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.

Quote:

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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.

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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.

Try

Code:

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dmesg | tail

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

Code:

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

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

Quote:

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Originally Posted by bigtomrodney

Try

Code:

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dmesg | tail

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

Code:

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

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

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Yeah, I have tried

Code:

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dmesg | tail

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but it does not want to accept -f.

Quote:

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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.

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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.

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.)

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.

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.

Code:

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while true;do sudo dmesg -c;done

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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. :-o