If the system has been corrupted, and there is no grub menu, then boot from a live CD, open a terminal and do this:

sudo fdisk -l # find the root filesystem
sudo mount /dev/sda2 /mnt #whatever your root filesystem is
D1=dev
D2=dev/pts
D3=proc
D4=sys
sudo mount --bind /$D1 /mnt/$D1 &&
sudo mount --bind /$D2 /mnt/$D2 &&
sudo mount --bind /$D3 /mnt/$D3 &&
sudo mount --bind /$D4 /mnt/$D4

sudo chroot /mnt # You are now back in the main hard drive

cd /etc/default
cp grub grub.orig
vi grub
# change timeout from 0 to 10
# change STYLE from hidden to menu
# remove # from Ter

To securely wipe a hard drive of all data, do:

apt install wipe
shred -vfz -n 2 /dev/sdb

• Options above are verbose, force, zero out in an extra pass
• Number of passes: -n 2

An alternative “light” way of doing this is to simply copy random bytes

D=sdb
fdisk -l /dev/$D # make sure we have the right device
dd if=/dev/urandom of=/dev/$D bs=4096 status=progress

• If the progress info is not sufficient, then from another terminal session do the following and updates will appear in the original terminal

pgrep -l '^dd$'   # gives the pid: nnnn DD
watch -n 60 kill

• List current tables with line numbers and stats

iptables -L INPUT --line-numbers -v

• Append another rule

iptables -A INPUT -s 58.245.23.126/24 -j DROP

• Delete rule #3

iptables -D INPUT 3

• The moment you apply IPTABLE rule it immediately becomes active.But it will not survive a reboot.
• To be able to survive IPTABLES a reboot in your network configuration file /etc/network/interfaces file (referring to a Debian/Ubuntu system) you need to add:

pre-up  iptables-restore < firewall.txt

Making changes persistent in CentOS 5

iptables rules are stored in memory.

Make sure userid’s and groupid’s match between the systems

• e.g. usermod -u 1001 -g 504 -c "Andrew Fountain" andrewf

Set up the server

• set up the fully qualified domain name, e.g.

The most minimal way of doing an installation is using sassc, the C binding.

apt install git build-essential
cd /opt
git clone https://github.com/sass/libsass.git
git clone https://github.com/sass/sassc.git libsass/sassc
echo 'SASS_LIBSASS_PATH="/opt/libsass"' >> /etc/environment
source /etc/environment
echo $SASS_LIBSASS_PATH # Make sure it worked…
cd libsass/sassc
make
ln -sn /opt/libsass/sassc/bin/sassc /usr/local/bin/

sassc file.scss file.css # run like this

• See crocodillon.com/…ass-on-ubuntu and gist.github.com/edoua

By default Ubuntu 16.04 (Xenial) now comes with php 7.0

You can install php 5.6 in parallel and switch between them using the following instructions:

add-apt-repository ppa:ondrej/php
apt update
apt install php5.6 libapache2-mod-php5.6 php5.6-curl php5.6-gd php5.6-mbstring php5.6-mcrypt php5.6-mysql php5.6-xml php5.6-xmlrpc
a2dismod php7.0
a2enmod php5.6
systemctl restart apache2

• See htt

Resources

• apt.syncthing.net Syncthing’s instructions for installing their PPA
• www.digitalocean.com/…tu-14-04 install from GitHub.

To install:

sudo apt-get install cups-pdf

There are a couple of pitfalls:

1. Getting unreadable PDF
   • Due to wrongly selecting ☒ print to file (which creates an EPS, not a pdf but can be read with some pdf tools
   • Just don’t be tempted to check this box!

1. A bad swap file entry in /etc/fstab stopped systemd from booting
2. systemd did’t like my ssd optimizations:
   • tmpfs /var/lock tmpfs defaults,noatime,mode=0755 0 0 # had to be commented out
   • had to do: mkdir /etc/tmpfiles.d/console-kit.conf to stop another error message

See ubuntuforums.org/…owthread.php

and bbs.archlinux.org/…ewtopic.php for explanations