Linux/Ubuntu

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Ubuntu

Ubuntu - Wikipedia

Subpages

Download

14.04 LTS: 

http://releases.ubuntu.com/14.04/

16.04 LTS: 

http://releases.ubuntu.com/16.04/

Architectures

"The desktop version of Ubuntu currently supports the Intel x86 and the AMD64 architectures. Some server releases also support the SPARC architecture in addition to Intel x86 and AMD64. Unofficial support is available for the PowerPC, IA-64 (Itanium) and PlayStation 3 architectures." [1]

Releases

Source: Ubuntu - Wikipedia

Version Code name Release date
4.10 Warty Warthog 2004-10-20
5.04 Hoary Hedgehog 2005-04-08
5.10 Breezy Badger 2005-10-13
6.06 LTS Dapper Drake 2006-06-01
6.10 Edgy Eft 2006-10-26
7.04 Feisty Fawn 2007-04-19
7.10 Gutsy Gibbon 2007-10-18
8.04 LTS Hardy Heron 2008-04-24
8.10 Intrepid Ibex 2008-10-30
9.04 Jaunty Jackalope 2009-04-23
9.1 Karmic Koala 10/29/2009
10.04 LTS Lucid Lynx 4/29/2010
10.1 Maverick Meerkat 10/10/2010
11.04 Natty Narwhal 4/28/2011
11.1 Oneiric Ocelot 10/13/2011
12.04 LTS Precise Pangolin 4/26/2012
12.1 Quantal Quetzal 10/18/2012
13.04 Raring Ringtail 4/18/2013

apt

See apt

apt repository

See apt/repository

Disable SSH Banner

Xbu4L.png

For single user: 

touch ~/.hushlogin

For all users, edit /etc/pam.d/sshd and comment out: 

session    optional     pam_motd.so  motd=/run/motd.dynamic noupdate
session    optional     pam_motd.so # [1]

References:

Services

List services: 

service --status-all
initctl list
initctl show-config

Status service: 

service [service] status

Start service: 

service [service] start

Stop service: 

service [service] stop

Restart service: 

service [service] restart

Remove service: 

update-rc.d -f [service] remove

Add service: 

update-rc.d [service] defaults

Current run level: 

runlevel

Specify service priorities: 

update-rc.d [service] defaults [START] [KILL]
update-rc.d apache2 defaults 90 90
update-rc.d mysql defaults 10 10
update-rc.d apache2 defaults 90  # 90 for both

Fully configure: 

update-rc.d apache2 start 10 2 3 4 5 . stop 90 0 1 6 .

References:

motd

Message of the Day: 

/etc/motd

Most of the noise comes from here: 

/etc/update-motd.d/*

Disable noise: 

mkdir /etc/update-motd.d/DISABLED
mv /etc/update-motd.d/* /etc/update-motd.d/DISABLED/

do-release-upgrade

Release upgrade: 

do-release-upgrade

Debug: [https://askubuntu.com/questions/125392/why-is-no-new-release-found-when-upgrading-from-a-lts-to-the-next\ 

export DEBUG_UPDATE_MANAGER=true

Firewall

ufw

Enable firewall: 

sudo ufw enable

Disable firewall: 

sudo ufw disable

Show rules: 

sudo ufw status
sudo ufw status numbered   # rule numbers
sudo ufw status verbose    # with port numbers

Allow traffic: 

sudo ufw allow 22/tcp  # SSH
sudo ufw allow 53/tcp

Disallow traffic 

sudo ufw deny 53/tcp

Delete rule: 

sudo ufw delete allow 53/tcp
sudo ufw delete 1    # rules from 'status numbered'

Rules are written to: 

 /lib/ufw/user.rules

References:

UFW Applications

/etc/ufw/applications.d/apache 

[Apache]
title=Web Server
description=Apache v2 is the next generation of the omnipresent Apache web server.
ports=80/tcp

[Apache Secure]
title=Web Server (HTTPS)
description=Apache v2 is the next generation of the omnipresent Apache web server.
ports=443/tcp

[Apache Full]
title=Web Server (HTTP,HTTPS)
description=Apache v2 is the next generation of the omnipresent Apache web server.
ports=80,443/tcp

/etc/ufw/applications.d/terraria 

[Terraria]
title=Terraria Server
description=Terraria Server
ports=7777/tcp

Make sure the application rule is not group writable: 

chmod 644 [RULE_FILE]

List applications: 

ufw app list

Application info: 

ufw app info [APP]

Allow: 

ufw allow Apache
ufw allow terraria

Disable Logging

To stop UFW from logging to dmesg, disable logging completely: [2] 

sudo ufw logging off

OR BETTER YET... 

# alias dmesg='dmesg | grep -v UFW'
alias dmesg='dmesg --color=always | grep -v UFW --color=always'

Add this to your .bashrc

rsyslog

Not logging to /var/log/syslog

Check the file permissions 

chown syslog /var/log/syslog *
service rsyslog restart

Run rsyslog in debug mode: [3] 

rsyslogd -c3 -dn

Ubuntu apt sources

Tip: search google for "ubuntu sources.list generator" [4]

Primary repositories: 

http://archive.ubuntu.com/ubuntu/dists/
http://security.ubuntu.com/ubuntu/dists/

Example 12.04 LTS (with sub repo branches, including universe) [5] 

deb http://us.archive.ubuntu.com/ubuntu/ precise main restricted universe
deb http://us.archive.ubuntu.com/ubuntu/ precise-security main restricted universe
deb http://us.archive.ubuntu.com/ubuntu/ precise-updates main restricted universe

Example 12.04 LTS (with sub repo branches, including universe separated) [6] 

deb http://us.archive.ubuntu.com/ubuntu/ precise main restricted
deb http://us.archive.ubuntu.com/ubuntu/ precise-security main restricted
deb http://us.archive.ubuntu.com/ubuntu/ precise-updates main restricted

deb http://us.archive.ubuntu.com/ubuntu/ precise universe
deb http://us.archive.ubuntu.com/ubuntu/ precise-security universe
deb http://us.archive.ubuntu.com/ubuntu/ precise-updates universe

Example 12.04 LTS default server install: (fio-benchmark vm) 

deb http://us.archive.ubuntu.com/ubuntu/ precise main restricted
deb-src http://us.archive.ubuntu.com/ubuntu/ precise main restricted
deb http://us.archive.ubuntu.com/ubuntu/ precise-updates main restricted
deb-src http://us.archive.ubuntu.com/ubuntu/ precise-updates main restricted
deb http://us.archive.ubuntu.com/ubuntu/ precise universe
deb-src http://us.archive.ubuntu.com/ubuntu/ precise universe
deb http://us.archive.ubuntu.com/ubuntu/ precise-updates universe
deb-src http://us.archive.ubuntu.com/ubuntu/ precise-updates universe
deb http://us.archive.ubuntu.com/ubuntu/ precise multiverse
deb-src http://us.archive.ubuntu.com/ubuntu/ precise multiverse
deb http://us.archive.ubuntu.com/ubuntu/ precise-updates multiverse
deb-src http://us.archive.ubuntu.com/ubuntu/ precise-updates multiverse
deb http://us.archive.ubuntu.com/ubuntu/ precise-backports main restricted universe multiverse
deb-src http://us.archive.ubuntu.com/ubuntu/ precise-backports main restricted universe multiverse
deb http://security.ubuntu.com/ubuntu precise-security main restricted
deb-src http://security.ubuntu.com/ubuntu precise-security main restricted
deb http://security.ubuntu.com/ubuntu precise-security universe
deb-src http://security.ubuntu.com/ubuntu precise-security universe
deb http://security.ubuntu.com/ubuntu precise-security multiverse
deb-src http://security.ubuntu.com/ubuntu precise-security multiverse

# or without source repos
deb http://us.archive.ubuntu.com/ubuntu/ precise main restricted
deb http://us.archive.ubuntu.com/ubuntu/ precise-updates main restricted
deb http://us.archive.ubuntu.com/ubuntu/ precise universe
deb http://us.archive.ubuntu.com/ubuntu/ precise-updates universe
deb http://us.archive.ubuntu.com/ubuntu/ precise multiverse
deb http://us.archive.ubuntu.com/ubuntu/ precise-updates multiverse
deb http://us.archive.ubuntu.com/ubuntu/ precise-backports main restricted universe multiverse
deb http://security.ubuntu.com/ubuntu precise-security main restricted
deb http://security.ubuntu.com/ubuntu precise-security universe
deb http://security.ubuntu.com/ubuntu precise-security multiverse

Reference:

sources.list generator

Tip: search google for "ubuntu sources.list generator"

Ubuntu Sources List Generator - http://repogen.simplylinux.ch/

Repository Components

The repository components are:

  • Main - Officially supported software.
  • Restricted - Supported software that is not available under a completely free license.
  • Universe - Community maintained software, i.e. not officially supported software.
  • Multiverse - Software that is not free.

The Ubuntu Install CDs contain software from the "Main" and "Restricted" components of the repositories.

References:

Networking

Network configuration folder: 

/etc/network/

Interfaces file: 

/etc/network/interfaces

Local loopback address: 

auto lo
iface lo inet loopback

DHCP Address: 

auto eth0
iface eth0 inet dhcp

Static Address: 

auto eth0
iface eth0 inet static
    address 192.168.1.5
    netmask 255.255.255.0
    gateway 192.168.1.254

---

Manually Configured Interface - not ifup (by external application) 

auto eth0
iface eth0 inet manual

Note: The 'auto' line or lines indicates which interfaces should be brought up with 'ifup -a'. [7]

Another way to configure: 

auto lo eth0 eth1

iface lo inet loopback

iface eth0 inet dhcp

iface eth1 inet static
    address 192.168.1.5
    netmask 255.255.255.0

References:

--- 

auto lo
iface lo inet loopback

iface eth0 inet dhcp
    hwaddress ether 36:f2:3b:e2:4f:2d
    auto eth0

Hostname

Change hostname 

hostname [newhostname] ; hostname > /etc/hostname

Should also update /etc/hosts for consistency

---

Edit /etc/hostname

Run 

sudo /etc/init.d/hostname.sh start
# or (depending on system)
service hostname start

PXE Install

Get netboot image from http://cdimage.ubuntu.com/netboot/ 

mkdir -p /tftpboot/pxe/images/ubuntu
cd /tftpboot/pxe/images/ubuntu
wget http://archive.ubuntu.com/ubuntu/dists/precise/main/installer-amd64/current/images/netboot/netboot.tar.gz
tar -zvxf netboot.tar.gz
cp ubuntu-installer/amd64/linux .
cp ubuntu-installer/amd64/initrd.gz .

Tools:

  • system-config-kickstart - graphical tool for creating Kickstart files
apt-get install system-config-kickstart

References:

---

My kickstart: 

install
text

#url --url http://uefi.int.fusionio.com/ubuntu/
url --url http://repo.int.fusionio.com/ubuntu/ubuntu

lang en_US
langsupport en_US
keyboard us
timezone America/Denver

#rootpw --disabled
rootpw password1
#user karl --fullname "karl" --iscrypted --password $1$tNU2BbnT$VX/2/60.GsgAoM6LEl8qs1
user fio --fullname "fio" --password password1
# asking about weak passwords for both root and fio

auth --useshadow --enablemd5
firewall --disabled

skipx

# bootloader --location=mbr
# zerombr yes
# clearpart --all --initlabel

reboot

%packages
openssh-server

%pre
echo "pre" > pre.txt

%post
echo "post" > post.txt

Sample kickstart: [8] 

#Generated by Kickstart Configurator
#platform=x86

#System language
lang en_US
#Language modules to install
langsupport en_US
#System keyboard
keyboard us
#System mouse
mouse
#System timezone
timezone America/New_York
#Root password
rootpw --disabled
#Initial user
user karl --fullname "karl" --iscrypted --password $1$tNU2BbnT$VX/2/60.GsgAoM6LEl8qs1
#Reboot after installation
reboot
#Use text mode install
text
#Install OS instead of upgrade
install
#Use CDROM installation media
cdrom
#System bootloader configuration
bootloader --location=mbr
#Clear the Master Boot Record
zerombr yes
#Partition clearing information
clearpart --all --initlabel
#System authorization infomation
auth --useshadow --enablemd5
#Firewall configuration
firewall --disabled
#Do not configure the X Window System
skipx
#Package install information
%packages
@ ubuntu-desktop
ftp
openssh-server
bsdmainutils
emacs21-common
emacs21-bin-common
libungif4g
xaw3dg
emacs21
emacsen-common
liblockfile1
libapr0
chess
binutils
gcc-4.0

My Kickstart Generated by Kickstart Configurator 

#Generated by Kickstart Configurator
#platform=AMD64 or Intel EM64T

#System language
lang en_US
#Language modules to install
langsupport en_US
#System keyboard
keyboard us
#System mouse
mouse
#System timezone
timezone --utc America/Denver
#Root password
rootpw password1
#Initial user
user fio --fullname "fio" --password password1
#Reboot after installation
reboot
#Use text mode install
text
#Install OS instead of upgrade
install
#Use Web installation
url --url http://uefi.int.fusionio.com/uefi
#System bootloader configuration
bootloader --location=mbr
#Clear the Master Boot Record
zerombr yes
#Partition clearing information
clearpart --all --initlabel
#Disk partitioning information
part /boot --fstype ext3 --size 100
part swap --size 1024
part / --fstype ext4 --size 1 --grow
#System authorization infomation
auth  --useshadow  --enablemd5
#Network information
network --bootproto=dhcp --device=eth0
#Firewall configuration
firewall --disabled
#Do not configure the X Window System
skipx
%pre --interpreter=python
test
%post --nochroot --interpreter=perl
test

Upstart

Start/Stop/Restart/Status service: 

/etc/init.d/[service] [start|stop|restart|status]
service [service] start
service [service] stop
service [service] restart
service [service] status

List services: 

ls /etc/init.d
service --status-all

Add/remove service: 

update-rc.d [service] defaults
update-rc.d [service] remove
update-rc.d [service] start 20 2 3 4 5 .
update-rc.d [service] start 20 2 3 4 5 . stop 20 0 1 6 .
update-rc.d [service] stop 45 S .

References:

Driver Disk

Ubiquity/DriverUpdates - Ubuntu Wiki - https://wiki.ubuntu.com/Ubiquity/DriverUpdates

Partner Linux Driver Process - http://www.novell.com/developer/partner_linux_driver_process.html

Provide driver on removable media during installation? - Ask Ubuntu - http://askubuntu.com/questions/6499/provide-driver-on-removable-media-during-installation

"Alternatively, if you want a quick and dirty solution and assuming this is a disk driver, put the kernel module in one of the following directories:" 

   /lib/modules/*/kernel/drivers/ide
   /lib/modules/*/kernel/drivers/scsi
   /lib/modules/*/kernel/drivers/block

Gnome Desktop

Install: 

apt-get install x-window-system-core
apt-get install gnome
apt-get install xterm
reboot

Repair: 

apt-get install --reinstall ubuntu-desktop

Ubuntu Desktop

Repair: 

apt-get install --reinstall ubuntu-desktop

Auto Login

sudo mkdir /etc/lightdm/lightdm.conf.d
cat > /etc/lightdm/lightdm.conf.d/50-myconfig.conf << "EOF"
[SeatDefaults]
autologin-user=USERNAME
EOF

Ref: https://help.ubuntu.com/community/AutoLogin

OR 

System Settings > User Accounts

xCOz0.png

Release Upgrade

Major release upgrade: (eg. Karmic Koala to Lucid Lynx) 

sudo do-release-upgrade

I used this to successfully upgrade a Karmic Koala (9.10) to Lucid Lynx (10.04 LTS). And then from Lucid Lynx (10.04 LTS) to Precise Pangolin (12.04 LTS).

References:

Samba

Samba and CIFS: 

sudo apt-get install cifs-utils

# older system:
sudo apt-get install smbfs

Mount: 

mount //fileserver.oeey.com/share /mnt -t cifs -o user=guest

Remote Desktop Sharing

VNC

#apt-get install tightvncserver
#apt-get install xterm
#apt-get install xfce4
#apt-get install xfonts-base

apt-get install tightvncserver xterm xfce4 xfonts-base

# set passwd
vncpasswd

# set empty passwd (after starting server to create xstartup template)
echo "" | vncpasswd -f > ~/.vnc/passwd

vncserver

~/.vnc/xstartup:
  startxfce4 &
  xterm &

Kill: 

killall Xtightvnc

Vino

Type “Desktop Sharing” into the dash and hit the configuration screen.

To disabled the encryption: 

sudo apt-get install vino dconf-editor

As the regular login user (NOT ROOT!): 

gsettings set org.gnome.Vino require-encryption false
gsettings set org.gnome.Vino prompt-enabled false
gsettings set org.gnome.Vino authentication-methods "['none']"

Or Access via gui: 

$ dconf-editor
org.gnome.desktop.remote-access

To auto start Vino on systems it doesn't auto start on (eg. Raspberry Pi) 

## sudo su -
## cat > /etc/sudoers.d/vsrv.sh << "EOF"
## #!/bin/bash
## /usr/lib/vino/vino-server
## EOF
## chmod +x /etc/sudoers.d/vsrv.sh
## 
## cat >> /etc/xdg/lxsession/LXDE/autostart << "EOF"
## @/etc/sudoers.d/vsrv.sh
## EOF

sudo su -
cat > /etc/xdg/autostart/vino-server.desktop << "EOF"
[Desktop Entry]
Name=Desktop Sharing
Comment=GNOME Desktop Sharing Server
Exec=/usr/lib/vino/vino-server
Terminal=false
Type=Application
X-GNOME-Autostart-Phase=Applications
X-GNOME-AutoRestart=true
NoDisplay=true
EOF

On Ubuntu this added: 

Exec=/usr/lib/vino/vino-server --sm-disable

Ubuntu 14 Sample: 

# cat /etc/xdg/autostart/vino-server.desktop
[Desktop Entry]
Name=Desktop Sharing
Comment=GNOME Desktop Sharing Server
Keywords=vnc;share;remote;
NoDisplay=true
Exec=/usr/lib/vino/vino-server --sm-disable
Icon=preferences-desktop-remote-desktop
OnlyShowIn=GNOME;Unity;
Terminal=false
Type=Application
AutostartCondition=GSettings org.gnome.Vino enabled
X-GNOME-Autostart-Phase=Applications
X-GNOME-AutoRestart=true
X-GNOME-UsesNotifications=true
X-Ubuntu-Gettext-Domain=vino

Manually run: 

pkill vino
export DISPLAY=:0.0
/usr/lib/vino/vino-server &


References:


Configure X11Vnc at startup

# ##################################################################
# Script Name : vnc-startup.sh
# Description : Perform an automated install of X11Vnc
#               Configure it to run at startup of the machine            
# Date : Feb 2016
# Written by : Griffon 
# Web Site :http://www.c-nergy.be - http://www.c-nergy.be/blog
# Version : 1.0
#
# Disclaimer : Script provided AS IS. Use it at your own risk....
#
# #################################################################
​
# Step 1 - Install X11VNC  
# ################################################################# 
sudo apt-get install x11vnc -y
​
# Step 2 - Specify Password to be used for VNC Connection 
# ################################################################# 
​
sudo x11vnc -storepasswd /etc/x11vnc.pass 
​
​
# Step 3 - Create the Service Unit File
# ################################################################# 
​
cat > /lib/systemd/system/x11vnc.service << EOF
[Unit]
Description=Start x11vnc at startup.
After=multi-user.target
​
[Service]
Type=simple
ExecStart=/usr/bin/x11vnc -auth guess -forever -loop -noxdamage -repeat -rfbauth /etc/x11vnc.pass -rfbport 5900 -shared
​
[Install]
WantedBy=multi-user.target
EOF
​
# Step 4 -Configure the Service 
# ################################################################ 
​
echo "Configure Services"
sudo systemctl enable x11vnc.service
sudo systemctl daemon-reload
​
sleep  5s
sudo shutdown -r now 
​

DHCP Hostname

DHCP Register Hostname

Getting Debian to send your DHCP server it's hostname for Dynamic DNS - http://jeffwelling.github.io/2010/01/02/Debian-dynamic-dns.html

Should already be enbaled by default: 

/etc/dhcp3/dhclient.conf
  send host-name = gethostname();

test with: 

nslookup [hostname]

Java

Java through PPRA Uprising

apt-get install gnupg2 software-properties-common
add-apt-repository ppa:linuxuprising/java
# answer question
apt-get install oracle-java17-installer oracle-java17-set-default
# answer TUI questions

ref: https://www.rosehosting.com/blog/how-to-install-java-17-lts-on-ubuntu-20-04/

Java 8

# For Ubuntu
add-apt-repository -y ppa:webupd8team/java
apt-get update
echo "oracle-java8-installer shared/accepted-oracle-license-v1-1 select true" | sudo debconf-set-selections
apt-get -y --force-yes install oracle-java8-installer oracle-java8-set-default

Console Only Mode

The Ubuntu 16 non gui systems struggle with the console.

1. The login screen isn't visible from console 1, and 2. the refresh rate is beyond terrible.

This can be fixed by simply commenting out a line (fix #1) and adding a line (fix #2):

/etc/default/grub: 

#GRUB_CMDLINE_LINUX_DEFAULT="quiet splash"

GRUB_TERMINAL=console

and then running: 

update-grub


ref: https://askubuntu.com/questions/92276/how-do-i-boot-into-true-text-mode

Maybe https://superuser.com/questions/1106174/boot-ubuntu-16-04-into-command-line-do-not-start-gui

Full Release Upgrade

sudo apt-get update
sudo apt-get upgrade
sudo apt-get dist-upgrade
sudo apt-get install update-manager-core
sudo do-release-upgrade

https://www.digitalocean.com/community/tutorials/how-to-upgrade-to-ubuntu-16-04-lts

Open VM Tools

VMware tools and drivers: 

apt install open-vm-tools open-vm-tools-desktop

Driver: 

apt install xserver-xorg-video-vmware xserver-xorg-input-vmmouse

Afterwards, restart the VM

Make sure the VM's display "Video card" device has "auto" set for RAM. Need to have sufficient to run the GUI. 3D support is not required.

LAMP

# sudo apt install apache2
# sudo apt install mysql-server
# sudo apt install php-pear php-fpm php-dev php-zip php-curl php-xmlrpc php-gd php-mysql php-mbstring php-xml libapache2-mod-php
sudo apt install apache2 mysql-server php-pear php-fpm php-dev php-zip php-curl php-xmlrpc php-gd php-mysql php-mbstring php-xml libapache2-mod-php

How to Install LAMP on Ubuntu  ·  How to Ubuntu - https://howtoubuntu.org/how-to-install-lamp-on-ubuntu

phpmyadmin: 

apt-get -y install phpmyadmin

Free SSL Certificate from Let's Encrypt

apt-get -y install python3-certbot-apache
certbot --apache -d example.com

Let's Encrypt SSL certificates are valid for a short period of 80 days only. Therefore a cronjob to auto-renew the SSL certificates is necessary that runs the certbot --renew command.

/etc/cron.d/certbot: 

# /etc/cron.d/certbot: crontab entries for the certbot package
#
# Upstream recommends attempting renewal twice a day
#
# Eventually, this will be an opportunity to validate certificates
# haven't been revoked, etc. Renewal will only occur if expiration
# is within 30 days.
SHELL=/bin/sh
PATH=/usr/local/sbin:/usr/local/bin:/sbin:/bin:/usr/sbin:/usr/bin

0 */12 * * * root test -x /usr/bin/certbot -a \! -d /run/systemd/system && perl -e 'sleep int(rand(43200))' && certbot -q renew

Ref: Ubuntu 18.04 (LTS) LAMP server tutorial with Apache, PHP 7.2, and MySQL - https://www.howtoforge.com/tutorial/install-apache-with-php-and-mysql-on-ubuntu-18-04-lamp/ 


You should test your configuration at:
https://www.ssllabs.com/ssltest/analyze.html?d=wiki.example.com

 - Congratulations! Your certificate and chain have been saved at:
   /etc/letsencrypt/live/wiki.example.com/fullchain.pem
   Your key file has been saved at:
   /etc/letsencrypt/live/wiki.example.com/privkey.pem
   Your cert will expire on 2018-11-21. To obtain a new or tweaked
   version of this certificate in the future, simply run certbot again
   with the "certonly" option. To non-interactively renew *all* of
   your certificates, run "certbot renew"

Mirror Repo

Install: 

# ubuntu
apt install apt-mirror
# centos
yum install apt-mirror

Create folder: 

mkdir -p /repo/apt-mirror

Run update: (after config below) 

apt-mirror


---

Ubunut 16.04:

/etc/apt/mirror.list 

############# config ##################
#
# set base_path    /var/spool/apt-mirror
set base_path    /repo/apt-mirror
#
# set mirror_path  $base_path/mirror
# set skel_path    $base_path/skel
# set var_path     $base_path/var
# set cleanscript $var_path/clean.sh
# set defaultarch  <running host architecture>
# set postmirror_script $var_path/postmirror.sh
# set run_postmirror 0
set nthreads     20
set _tilde 0
#
############# end config ##############

deb http://archive.ubuntu.com/ubuntu xenial main restricted universe multiverse
deb http://archive.ubuntu.com/ubuntu xenial-security main restricted universe multiverse
deb http://archive.ubuntu.com/ubuntu xenial-updates main restricted universe multiverse
#deb http://archive.ubuntu.com/ubuntu xenial-proposed main restricted universe multiverse
deb http://archive.ubuntu.com/ubuntu xenial-backports main restricted universe multiverse

deb-src http://archive.ubuntu.com/ubuntu xenial main restricted universe multiverse
deb-src http://archive.ubuntu.com/ubuntu xenial-security main restricted universe multiverse
deb-src http://archive.ubuntu.com/ubuntu xenial-updates main restricted universe multiverse
#deb-src http://archive.ubuntu.com/ubuntu xenial-proposed main restricted universe multiverse
deb-src http://archive.ubuntu.com/ubuntu xenial-backports main restricted universe multiverse

clean http://archive.ubuntu.com/ubuntu

This would be /etc/apt-mirror.list on Centos


--- ref

Host Your Own YUM and APT Repository – Engineering Tomorrow’s Systems - https://estl.tech/host-your-own-yum-and-apt-repository-4ba8350eeda1

Install Pip with Easy Install

pip via package seems broken, especially on "pip install pip --upgrade". Installing with easy_install seems to work better. 

apt-get install python-setuptools
easy_install pip
pip install pip --upgrade

---

Ubuntu 18 removed easy_install from python-setuptools 

According to the changelog easy_install was removed from the python-setuptools package.
https://launchpad.net/ubuntu/+source/python-setuptools/39.0.1-2

python /usr/lib/python2.7/dist-packages/easy_install.py pip
pip install pip --upgrade

Extract deb Package Contents

$ ar x example.deb
$ ar -xv example.deb
x - debian-binary
x - control.tar.gz
x - data.tar.xz

$ tar -xvf control.tar.gz

$ dpkg -x package.deb /tmp/out

Ref: [9]

Keep Ubuntu from releasing DHCP address on reboot

For crappy networks with crappy DHCP lease times...

Prevent DHCP release upon shutdown? - Raspberry Pi Forums - https://www.raspberrypi.org/forums/viewtopic.php?t=72579

When you shut down your RPi, the /etc/init.d/networking script is invoqued, called by the rc.d hooks. In turn, the /etc/init.d/networking execute ifdown -a in the "stop)" and the "reload)" case switches. Just comment out these lines. Even better, if you want to deconfigure gracefully the interfaces before shut down, replace the ifdown command by the appropriate ip link set eth0 down command. I just checked with tcpdump, no DHCPRELEASE is sent in that case. 

/etc/init.d/networking
# Comment out the 'ifdown -a' section in the stop) case

stop)
...
        #log_action_begin_msg "Deconfiguring network interfaces"
        #if ifdown -a --exclude=lo $verbose; then
        #    log_action_end_msg $?
        #else
        #    log_action_end_msg $?
        #fi

FTDI Driver

The Linux kernel team decided to remove some modules from the base kernel to allow "virtual" images to be slimmed down. The extra modules are moved into linux-image-extra and you can get them installed by typing: 

apt install linux-image-extra-virtual
apt install linux-image-extra-`uname -r`

modprobe usbserial
modprobe ftdi_sio

ref: [10]

resolv.conf

"For years it’s been simple to set up DNS on a Linux machine. Just add a couple of entries to /etc/resolv.conf and you’re done. But things change and now it’s not that simple. If you now edit /etc/resolv.conf on Ubuntu you’ll find that the edits are ephemeral."

To fix this, install resolvconf and edit the head file. The changes will persist. 

sudo apt install resolvconf

/etc/resolvconf/resolv.conf.d/head
  nameserver 8.8.4.4
  nameserver 8.8.8.8

sudo service resolvconf restart

Default Kernels

Ubuntu	Code name		Linux kernel version
24.04	Noble Numbat		6.6
22.04	Jammy Jellyfish		5.15
20.04	Focal Fossa		5.4
18.04	Bionic Beaver		4.15
16.04	Xenial Xerus		4.4
14.04	Trusty Tahr		3.13
12.04	Precise Pangolin	3.2+

ref: https://askubuntu.com/questions/517136/list-of-ubuntu-versions-with-corresponding-linux-kernel-version

--- 

ubuntu-16.04.6-server-amd64.iso - 4.4.0-142-generic
   available: linux-image-4.15.0-46-generic

-

ubuntu-18.04.1-server-amd64.iso - 4.15.0-29-generic
   available: linux-image-4.18.0-16-generic

ubuntu-18.04.2-server-amd64.iso - 4.15.0-45-generic
   available: linux-image-4.18.0-16-generic

ubuntu-18.04.2-live-server-amd64.iso - 4.15.0-46-generic
   available: linux-image-4.18.0-16-generic

ubuntu-18.10-live-server-amd64.iso - 4.18.0-16-generic
   available: linux-image-4.18.0-16-generic

Sample APT: 

linux-image-4.18.0-10-generic


Cheat way to list available: 

$ apt install linux-image
Package linux-image is a virtual package provided by:
...
  linux-image-4.18.0-16-lowlatency 4.18.0-16.17~18.04.1
  linux-image-4.18.0-16-generic 4.18.0-16.17~18.04.1
You should explicitly select one to install.

List current installed: 

# dpkg --list | grep linux-image
ii  linux-image-4.15.0-46-generic         4.15.0-46.49                      amd64        Signed kernel image generic
ii  linux-image-generic                   4.15.0.46.48                      amd64        Generic Linux kernel image

Install Ping Dig Traceroute

apt-get install iputils-ping dnsutils traceroute

Issues

Slow NFS Mount

Ubuntu 14.04 NFS4 client has slow access to NFS - share

Syslog shows: 

RPC: AUTH_GSS upcall timed out.
Please check user daemon is running.

/etc/modprobe.d/savenfs.conf 

# ken
blacklist rpcsec_gss_krb5

unload module: 

modprobe -r rpcsec_gss_krb5

And remount, should be instant.

References:

runit socket upstart connection refused

15.04 - Failed to connect to socket /com/ubuntu/upstart: Connection refused: Errors were encountered while processing: runit - Ask Ubuntu https://askubuntu.com/questions/654951/failed-to-connect-to-socket-com-ubuntu-upstart-connection-refused-errors-were 

vim /var/lib/dpkg/info/runit.postinst

Comment out: 

#if [ -x /sbin/start ]; then #provided by upstart
#  /sbin/start runsvdir
#fi

Finish install: 

sudo apt-get install -f

--

apt - How to fix processing with runit and git-daemon-run - Ask Ubuntu https://askubuntu.com/questions/765565/how-to-fix-processing-with-runit-and-git-daemon-run 

sudo apt-get purge runit
sudo apt-get purge git-all
sudo apt-get purge git
sudo apt-get autoremove
sudo apt update
sudo apt install git

Default Kernel

/etc/default/grub

Find the line that contains GRUB_DEFAULT - this is what you'll want to edit to set the default. You must know the full name of the kernel you want - e.g. Ubuntu, with Linux 3.13.0-53-generic - along with the full name of the "advanced menu" - e.g. Advanced options for Ubuntu.

You then combine those two strings with > and set GRUB_DEFAULT to them as: GRUB_DEFAULT="Advanced options for Ubuntu>Ubuntu, with Linux 3.13.0-53-generic" (including quotes).

Save it, then build the updated grub menu.

sudo update-grub

ref: [11]

keywords

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