[CentOS] print something on console after boot

Thu Dec 11 14:30:18 UTC 2014
James B. Byrne <byrnejb at harte-lyne.ca>

On Wed, December 10, 2014 17:51, Gordon Messmer wrote:
> On 12/10/2014 12:47 PM, Dan Hyatt wrote:
>> I've a virtual instance and I need to know its IP address after it has
>> finished booting up, to know where to ssh into it. I've tried adding
>> "ip -4 addr > /dev/tty0" to rc.local, but that obviously doesn't work,
>> because the login prompt overwrites everything I do.
>
> The easy answer would be: don't fight the login prompt.  "agetty" writes
> the contents of /etc/issue to the console before the login prompt.  If
> /etc/issue contains "\4" then agetty will print the IPv4 address to the
> console.
>
> See the man page for agetty, and update /etc/issue.
>
>

I find that CentOS-6 evidently does not support \; nor many of the /etc/issue
flags defined in man 1 agetty:

/etc/issue
CentOS release 6.6 (Final)
Kernel \r on an \m

Test: b:\b d:\d s:\s l:\l m:\m n:\n o:\o O:\O r:\r t:\t u:\u 0:\0 4:\4 6:\6


login:

CentOS release 6.6 (Final)
Kernel 2.6.32-504.1.3.el6.centos.plus.x86_64 on an x86_64

Test: b: d:09:19 on Thursday, 11 December 2014 s:Linux l:7 m:x86_64
n:vhost04.hamilton.harte-lyne.ca o: O: r:2.6.32-504.1.3.el6.centos.plus.x86_64
t:09:19 on Thursday, 11 December 2014 u: 0: 4: 6:

For ease in analysis (note that flags \0, \4, and \6 are not defined in agetty):

b:
d:09:19 on Thursday, 11 December 2014
s:Linux
l:7
m:x86_64
n:vhost04.hamilton.harte-lyne.ca
o:
O:
r:2.6.32-504.1.3.el6.centos.plus.x86_64
t:09:19 on Thursday, 11 December 2014
u:
0:
4:
6:

Is there some configuration issue of which I am unaware?  Where is the flag \4
usage defined?

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