On 31/05/2020 14.49, Sami Kerola wrote:
On Sat, 30 May 2020 at 15:08, Konstantin Khlebnikov
<khlebnikov@xxxxxxxxxxxxxx> wrote:
Option --follow-new (-W) works the same as --follow (-w) but initially
seeks to the end of kernel ring buffer, so it prints only new messages.
Useful for capturing kernel messages during actions without past log.
Hello Konstantin,
I wonder if it would be more useful to add '-n, --lines=[+]NUM' that
would be similar
to tail(1) option and argument. The --follow-new with an option that
lists NUM last
messages would be --lines=0
That said should --since and --until options similar to journalctl(1)
be considered
as well?
I don't see how this could be useful. If anybody interested in past
messages then showing whole buffer isn't a big deal - it's only few kb.
Anyway, without --follow this is simply 'dmesg | tail -n NUM'.
Implementation is also non-trivial - currently dmesg reads and prints
messages from /dev/kmsg in a loop. It doesn't know how many lines left.
/dev/kmsg doesn't support lseek with non-zero offset, only SET/DATA/END.
