Dmesg with date possible?

System1 · March 17, 2014, 9:47am

Hi there,

I miss date information when executing # dmesg

Is it possible to add this a date information to my results of # dmesg
?

Best wishes

Akshay_Hegde · March 17, 2014, 9:55am

Did you try dmesg -T ?

---------- Post updated at 08:25 PM ---------- Previous update was at 08:24 PM ----------

$ dmesg --v
dmesg from util-linux 2.20.1

System1 · March 17, 2014, 10:27am

dmesg -T is not available von HP Unix
man dmesg is also not helpful

Unixsystem is version 11.31

Akshay_Hegde · March 17, 2014, 10:31am

Okay, try this perl script, not written by me, but this might help you

$ cat time.pl 
#!/usr/bin/perl -wn
use strict;
 
foreach my $line (<>) {
    my ($uptime) = do { local @ARGV='/proc/uptime';<>}; ($uptime) = ($uptime =~ /^(\d+)\./);
    $line=~/^\[\s*(\d+)\.\d+\](.+)/;
    printf "[%s]%s\n", scalar localtime(time - $uptime + $1), $2;
}

usage :

$ dmesg | perl time.pl

vbe · March 17, 2014, 11:00am

Normally its the first thing written by dmesg...
typing just dmesg |more produces (sorry no HPUX11.31...):

Mar 17 15:59
gate64: sysvec_vaddr = 0xc0002000 for 2 pages
NOTICE: autofs_link(): File system was registered at index 3.
. etc

System1 · March 17, 2014, 11:08am

akshay hegde:

$ cat time.pl 
#!/usr/bin/perl -wn
use strict;
 
foreach my $line (<>) {
   my ($uptime) = do { local @ARGV='/proc/uptime';<>}; ($uptime) = ($uptime =~ /^(\d+)\./);
   $line=~/^\[\s*(\d+)\.\d+\](.+)/;
   printf "[%s]%s\n", scalar localtime(time - $uptime + $1), $2;
}

usage :

$ dmesg | perl time.pl

That didn't work ;(

# dmesg | perl time.pl | more
syntax error at time.pl line 1, near "$ cat time"
"use" not allowed in expression at time.pl line 3, at end of line
Execution of time.pl aborted due to compilation errors.

I tried this one:

#!/usr/bin/perl -wn
use strict;
foreach my $line (<>) {
    my ($uptime) = do { local @ARGV='/proc/uptime';<>}; ($uptime) = ($uptime =~ /^(\d+)\./);
    $line=~/^\[\s*(\d+)\.\d+\](.+)/;
    printf "[%s]%s\n", scalar localtime(time - $uptime + $1), $2;
}

But it's also not working ;(

Can't open /proc/uptime: No such file or directory at time.pl line 5.
Use of uninitialized value in pattern match (m//) at time.pl line 5.
Use of uninitialized value in subtraction (-) at time.pl line 7.
Use of uninitialized value in addition (+) at time.pl line 7.
Use of uninitialized value in printf at time.pl line 7.

dmesg | more

... doesn't show date - just on the top I could see the actual date ;-(

Corona688 · March 17, 2014, 11:13am

If dmesg doesn't show date, how could something else going to add date?

vbe · March 17, 2014, 11:19am

Exactly the only date you will get is that of dmesg execution... look at the man pages!

I wonder if you are not confusing with what you see in syslog.log file...

Akshay_Hegde · March 17, 2014, 11:40am

@Corona688 I don't know much about it, its looks like dmesg output is in nanoseconds from this article How to enable time stamps for logs in 'dmesg' on Gaia OS and SecurePlatform OS, I didn't go much into it since my system supports -T option.

Corona688 · March 17, 2014, 11:54am

Good point. Right now that's a mystery. If the OP could post some output, that would be nice. If it doesn't have timestamps already, we can't really add them.

Akshay_Hegde · March 17, 2014, 11:55am

Yes, thats true.

System1 · March 19, 2014, 2:17am

Now there are no new messages shown. Here's an example.

# dmesg
0/0/0/10/0/0/1.0x5006016930201d6b.0x400d000000000000 eslpt
0/0/0/10/0/0/0.0x5006016930201d6b.0x400e000000000000 eslpt
0/0/0/10/0/0/1.0x5006016930201d6b.0x400e000000000000 eslpt
0/0/0/10/0/0/0.0x5006016930201d6b.0x4014000000000000 eslpt
0/0/0/10/0/0/1.0x5006016930201d6b.0x4014000000000000 eslpt
0/0/0/10/0/0/0.1.3.255.0 fcd_vbus
0/0/0/10/0/0/0.1.3.253.0.0 tgt
0/0/0/10/0/0/1.2.3.255.0 fcd_vbus
0/0/0/10/0/0/0.1.3.253.0.0.0 sctl
0/0/0/10/0/0/1.2.3.253.0.0 tgt
0/0/0/10/0/0/1.2.3.253.0.0.0 sctl
0/0/0/10/0/0/0.1.3.0.0 fcd_vbus
0/0/0/10/0/0/0.1.3.0.0.0 tgt
0/0/0/10/0/0/0.1.3.0.0.0.1 sdisk
0/0/0/10/0/0/1.2.3.0.0 fcd_vbus
0/0/0/10/0/0/1.2.3.0.0.0 tgt
0/0/0/10/0/0/1.2.3.0.0.0.1 sdisk
0/0/0/10/0/0/0.1.3.0.0.0.2 sdisk

There's no need to have a date here but sometimes we have problems after one or two weeks so it would be very helpful to have a date in this situation.

;-(

ahamed101 · March 19, 2014, 3:00am

a thought - why not clear the messages everyday after storing it into a log file with current date? a cron should do.

---------- Post updated at 11:53 PM ---------- Previous update was at 11:48 PM ----------

I just noticed the logs are already rotated. Not sure if your system does it. Check these files

root@maximus:/tmp# ls -lrt /var/log/dmes*
-rw-r----- 1 root adm     28 Jan  8 09:39 /var/log/dmesg.4.gz
-rw-r----- 1 root adm  13463 Feb 17 00:53 /var/log/dmesg.3.gz
-rw-r----- 1 root adm  13376 Feb 17 19:41 /var/log/dmesg.2.gz
-rw-r----- 1 root adm  13544 Feb 19 19:57 /var/log/dmesg.1.gz
-rw-r----- 1 root adm  49431 Feb 23 12:36 /var/log/dmesg.0
-rw-r----- 1 root adm  49773 Mar  2 16:27 /var/log/dmesg

On a second thought I guess these are created either when the system boots up or shuts down.

---------- Post updated 03-19-14 at 12:00 AM ---------- Previous update was 03-18-14 at 11:53 PM ----------

Script log_dmesg

#!/bin/bash
echo "<< Log for $(date) >>" >> /var/log/mydmesg.log
dmesg >> /var/log/mydmesg.log
dmesg -C

Cron entry

0 0 * * * /path/to/your/script/log_dmesg

and may be include some log rotation logic if needed.