tar -cvjSf filename.tar.bz2 foldername
-c create
-v verboase
-j bzip2
-S Sparse files handled efficiently
-f filename

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

See user manual here: www.gnu.org/…escue_manual.html

• Install with apt install gddrescue

Example script:

• /dev/sdc is the bad drive which is being recovered to /dev/sdb

# first pass to copy the good sectors and make a log file of the bad
ddrescue -n /dev/sdc /dev/sdb logfile
# second pass keeps retrying the bad sectors
ddrescue -dr3 /dev/sdc /dev/sdb logfile

# have a look at what we have and do some validation
fdisk /dev/sdb
e2fsck -v -f /dev/sdb1
e2fsck -v -f /dev/sdb2

# It might be necessary to manually copy partition

• 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.

Undeleting a file is not easy in Linux.
However, if it's a text file, and you know a phrase from it, you can search the whole drive for the contents:
```
grep -a -C 200 -F "words in file" /dev/hda1 | more #change /dev/hda1 to whatever is appropriate
```

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.

using smartmontools documentation, try:

smartctl -d sat,16 -i /dev/sdc # find if enabled
smartctl -d sat,16 -a /dev/sdc # display all info

more documentation:

• www.smartmontools.org/…tl.8.in
• www.cyberciti.biz/…ailing.html
• it.toolbox.com/…ng-to-do-31523

I you get “device is busy” when running umount, try

sudo lsof | grep /dev/xxxx
# or
sudo fuser -cu /dev/xxxx

• SCL is the way to go since it has RedHat’s blessing

Note that it is the .conf file that controls which version of php is used. For some reason this does not seem to be available for php55.