구차니의 잡동사니 모음

$ sudo vi /etc/X11/xorg.conf

Section "ServerFlags"

    Option "DontVTSwitch" "true"

EndSection 

$ sudo sysctl disable serial-getty@ttySAC1.service

sysctl: cannot stat /proc/sys/disable: No such file or directory

sysctl: cannot stat /proc/sys/serial-getty@ttySAC1/service: No such file or directory

$ ll /proc/sys

total 0

dr-xr-xr-x   1 root root 0 ene  1  2000 ./

dr-xr-xr-x 150 root root 0 ene  1  1970 ../

dr-xr-xr-x   1 root root 0 oct 12 00:57 debug/

dr-xr-xr-x   1 root root 0 oct 12 00:57 dev/

dr-xr-xr-x   1 root root 0 ene  1  2000 fs/

dr-xr-xr-x   1 root root 0 ene  1  2000 kernel/

dr-xr-xr-x   1 root root 0 ene  1  2000 net/

dr-xr-xr-x   1 root root 0 ene  1  2000 vm/ 

$ sudo vi /etc/sysctl.conf

kernel.printk = 0 4 1 7 

# sysctl -w kernel.printk="2 4 1 7"

kernel.printk = 2 4 1 7

# sysctl kernel.printk

kernel.printk = 2       4       1       7

$ sysctl kernel.printk

kernel.printk = 1       4       1       7 

$ lscpu

Architecture:          armv7l

Byte Order:            Little Endian

CPU(s):                4

On-line CPU(s) list:   0-3

Thread(s) per core:    1

Core(s) per socket:    4

Socket(s):             1 

sudo apt-get install apache2

sudo apt-get install php4

sudo apt-get install libapache2-mod-php4

sudo /etc/init.d/apache2 restart 

These lines are irrelevant to kernel upgrades. And also that is not good to comment them. You will not be able to install some packages if you do it.

You can freeze any package including kernel packages by

sudo apt-mark hold <package_name>

for example

sudo apt-mark hold linux-image-generic linux-headers-generic

But you need to check which kernel meta-package is installed for LTS versions. It may be linux-generic-lts-utopic, etc. 

Hold a package:

sudo apt-mark hold package_name

Remove the hold:

sudo apt-mark unhold package_name 

$ apt-cache search linux-image-generic

linux-image-generic - Generic Linux kernel image

linux-image-generic-lts-raring - Generic Linux kernel image

linux-image-generic-lts-saucy - Generic Linux kernel image

linux-image-generic-lts-trusty - Generic Linux kernel image

linux-image-generic-lpae - Generic Linux kernel image

linux-image-generic-lpae-lts-saucy - Generic Linux kernel image

linux-image-generic-lpae-lts-trusty - Generic Linux kernel image

linux-image-highbank - Linux kernel image for the armhf architecture.

linux-image-omap - Linux kernel image for the armhf architecture.

linux-image-generic-lts-utopic - Generic Linux kernel image

linux-image-generic-lts-vivid - Generic Linux kernel image

linux-image-generic-lts-wily - Generic Linux kernel image

linux-image-generic-lts-xenial - Generic Linux kernel image

linux-image-generic-lpae-lts-utopic - Generic Linux kernel image

linux-image-generic-lpae-lts-vivid - Generic Linux kernel image

linux-image-generic-lpae-lts-wily - Generic Linux kernel image

linux-image-generic-lpae-lts-xenial - Generic Linux kernel image 

timeout 10;

lease {

interface "eth0";

fixed-address 10.0.0.10;

option subnet-mask 255.255.255.0;

renew 2 2022/1/1 00:00:01;

rebind 2 2022/1/1 00:00:01;

expire 2 2022/1/1 0:00:01;

} 

or you can assign a second IP to the interface like /etc/network/interfaces

auto lo

iface lo inet loopback

iface eth0 inet dhcp

auto eth0:1

iface eth0:1 inet static

address 10.10.10.2

netmask 255.255.255.0

The timeout statement

timeout time ;

The timeout statement determines the amount of time that must pass between the time that the client begins to try to determine its address and the time that it decides that it's not going to be able to contact a server. By default, this timeout is sixty seconds. After the timeout has passed, if there are any static leases defined in the configuration file, or any leases remaining in the lease database that have not yet expired, the client will loop through these leases attempting to validate them, and if it finds one that appears to be valid, it will use that lease's address. If there are no valid static leases or unexpired leases in the lease database, the client will restart the protocol after the defined retry interval.Lease Declarations

The lease declaration

lease { lease-declaration [ ... lease-declaration ] }

The DHCP client may decide after some period of time (see PROTOCOL TIMING) that it is not going to succeed in contacting a server. At that time, it consults its own database of old leases and tests each one that has not yet timed out by pinging the listed router for that lease to see if that lease could work. It is possible to define one or more fixed leases in the client configuration file for networks where there is no DHCP or BOOTP service, so that the client can still automatically configure its address. This is done with the lease statement.

NOTE: the lease statement is also used in the dhclient.leases file in order to record leases that have been received from DHCP servers. Some of the syntax for leases as described below is only needed in the dhclient.leases file. Such syntax is documented here for completeness.

A lease statement consists of the lease keyword, followed by a left curly brace, followed by one or more lease declaration statements, followed by a right curly brace. The following lease declarations are possible:

$ vi /etc/dhcp/dhclient.conf

# Configuration file for /sbin/dhclient, which is included in Debian's

#       dhcp3-client package.

#

# This is a sample configuration file for dhclient. See dhclient.conf's

#       man page for more information about the syntax of this file

#       and a more comprehensive list of the parameters understood by

#       dhclient.

#

# Normally, if the DHCP server provides reasonable information and does

#       not leave anything out (like the domain name, for example), then

#       few changes must be made to this file, if any.

#

option rfc3442-classless-static-routes code 121 = array of unsigned integer 8;

#send host-name "andare.fugue.com";

send host-name = gethostname();

#send dhcp-client-identifier 1:0:a0:24:ab:fb:9c;

#send dhcp-lease-time 3600;

#supersede domain-name "fugue.com home.vix.com";

#prepend domain-name-servers 127.0.0.1;

request subnet-mask, broadcast-address, time-offset, routers,

        domain-name, domain-name-servers, domain-search, host-name,

        dhcp6.name-servers, dhcp6.domain-search,

        netbios-name-servers, netbios-scope, interface-mtu,

        rfc3442-classless-static-routes, ntp-servers,

        dhcp6.fqdn, dhcp6.sntp-servers;

#require subnet-mask, domain-name-servers;

#timeout 60;

#retry 60;

#reboot 10;

#select-timeout 5;

#initial-interval 2;

#script "/etc/dhcp3/dhclient-script";

#media "-link0 -link1 -link2", "link0 link1";

#reject 192.33.137.209;

#alias {

#  interface "eth0";

#  fixed-address 192.5.5.213;

#  option subnet-mask 255.255.255.255;

#}

#lease {

#  interface "eth0";

#  fixed-address 192.33.137.200;

#  medium "link0 link1";

#  option host-name "andare.swiftmedia.com";

#  option subnet-mask 255.255.255.0;

#  option broadcast-address 192.33.137.255;

#  option routers 192.33.137.250;

#  option domain-name-servers 127.0.0.1;

#  renew 2 2000/1/12 00:00:01;

#  rebind 2 2000/1/12 00:00:01;

#  expire 2 2000/1/12 00:00:01;

#} 

$ sudo vi /etc/dhcp/dhclient-enter-hooks.d/debug

RUN="yes"

                                echo "$var='${!var}'" >> /tmp/dhclient-script.debug 

[링크 : https://lists.debian.org/debian-user/2010/10/msg00375.html]

Wed Oct 5 21:23:43 KST 2016: entering /sbin, dumping variables.

reason='PREINIT'

interface='eth0'

--------------------------

Wed Oct 5 21:23:54 KST 2016: entering /sbin, dumping variables.

reason='FAIL'

interface='eth0'

--------------------------

Wed Oct 5 21:24:10 KST 2016: entering /sbin, dumping variables.

reason='PREINIT'

interface='eth0'

--------------------------

Wed Oct 5 21:24:11 KST 2016: entering /sbin, dumping variables.

reason='TIMEOUT'

interface='eth0'

new_ip_address='192.168.219.130'

new_network_number='192.168.219.0'

new_subnet_mask='255.255.255.0'

new_broadcast_address='192.168.219.255'

new_routers='192.168.219.1'

new_domain_name_servers='1.214.68.2 61.41.153.2'

--------------------------

Wed Oct 5 21:24:14 KST 2016: entering /sbin, dumping variables.

reason='FAIL'

interface='eth0'

--------------------------

Wed Oct 5 21:27:14 KST 2016: entering /sbin, dumping variables.

reason='FAIL'

interface='eth0'

--------------------------

Wed Oct 5 21:27:40 KST 2016: entering /sbin, dumping variables.

reason='PREINIT'

interface='eth0'

--------------------------

Wed Oct 5 21:27:41 KST 2016: entering /sbin, dumping variables.

reason='BOUND'

interface='eth0'

new_ip_address='192.168.219.130'

new_network_number='192.168.219.0'

new_subnet_mask='255.255.255.0'

new_broadcast_address='192.168.219.255'

new_routers='192.168.219.1'

new_domain_name_servers='1.214.68.2 61.41.153.2'

old_ip_address='192.168.219.130'

old_network_number='192.168.219.0'

old_subnet_mask='255.255.255.0'

old_broadcast_address='192.168.219.255'

old_routers='192.168.219.1'

old_domain_name_servers='1.214.68.2 61.41.153.2'

-------------------------- 

Expire

The DHCP client has failed to renew its lease or acquire a new one, and the lease has expired. The IP address must be relinquished, and all related parameters should be deleted, as in RENEW and REBIND.

Fail

The DHCP client has been unable to contact any DHCP servers, and any leases that have been tested have not proved to be valid. The parameters from the last lease tested should be deconfigured. This can be handled in the same way as EXPIRE.

Timeout

The DHCP client has been unable to contact any DHCP servers. However, an old lease has been identified, and its parameters have been passed in as with BOUND. The client configuration script should test these parameters and, if it has reason to believe they are valid, should exit with a value of zero. If not, it should exit with a nonzero value.

The usual way to test a lease is to set up the network as with REBIND (since this may be called to test more than one lease) and then ping the first router defined in $routers. If a response is received, the lease must be valid for the network to which the interface is currently connected. It would be more complete to try to ping all of the routers listed in $new_routers, as well as those listed in $new_static_routes, but current scripts do not do this.