Linux world the guide you need

Linux world the guide you need

When to switch to Linux ?

is a powerfull stable platform that allows us to achieve many of (Penetration – Hosting – ..etc) tasks that can’t be done in Windows platform easily. On this article I will highlight most of the useful tools and commands that you will need while managing servers or desktops.

Usefull Commands Index:


Good Linux Flavors:



Usefull Packages:

For CentOs where you host websites additionally you will need the following packages:

  • Htop to view system usage CPU + ram ..etc better than Linux top command.
  • Mytop to view MySQL database queries.
  • CSF user friendly and powerful firewall.
  • CXS exploit scanner.
  • CalmAv Anti virus for Linux.
  • Cpanel user friendly OS management software.


Packages and Installation
To install cxs exploit scanner:

wget  # Get the install script from
tar -xzf cxsinstaller.tgz
rm -fv cxsinstaller.*

To install prm:

tar xvfz prm-current.tar.gz
cd prm-*/

To install csf firewall:

tar -xzf csf.tgz
cd csf

To install htop:

rpm -Uvh htop-1.0.3-1.el6.rf.x86_64.rpm

To remove rpm package htop as an example:

rpm -e htop

How to install Apache + PHP + Mysql on Ubuntu box:

sudo su
apt-get install apache2 -y
apt-get install php5 libapache2-mod-php5 -y
apt-get install mysql-server mysql-client -y
/etc/init.d/apache2 restart
sudo a2enmod ssl
sudo ln -s /etc/apache2/sites-available/default-ssl /etc/apache2/sites-enabled/000-default-ssl
sudo /etc/init.d/apache2 restart
cd /var/www

Update Apcache and PHP vis ssh:


To update Mysql:


Force ftp to update via ssh if cpanel is installed:

/scripts/ftpup --force

Install ms fonts on Ubuntu or Linux Mint:

sudo apt-get install msttcorefonts

Updating ubuntu:

update Ubuntu
apt-get update
apt-get upgrade
apt-get update && apt-get dist-upgrade

Update Backtrack:

update ubuntu
apt-get update
apt-get upgrade
apt-get update && apt-get dist-upgrade
apt-get install libcrafter blueranger dbd inundator intersect mercury cutycapt trixd00r artemisa rifiuti2 netgear-telnetenable jboss-autopwn deblaze sakis3g voiphoney apache-users phrasendrescher kautilya manglefizz rainbowcrack rainbowcrack-mt lynis-audit spooftooph wifihoney twofi truecrack uberharvest acccheck statsprocessor iphoneanalyzer jad javasnoop mitmproxy ewizard multimac netsniff-ng smbexec websploit dnmap johnny unix-privesc-check sslcaudit dhcpig intercepter-ng u3-pwn binwalk laudanum wifite tnscmd10g bluepot dotdotpwn subterfuge jigsaw urlcrazy creddump android-sdk apktool ded dex2jar droidbox smali termineter bbqsql htexploit smartphone-pentest-framework fern-wifi-cracker powersploit webhandler

Removing old kernels to have space for new kernel installations (/boot) – CentOS:
Recommended way:

#Edit /etc/yum.conf and set the following parameter
yum install yum-utils 
package-cleanup --oldkernels --count=2
#Done. This will erase in a good fashion the old kernels, and, keep just the last 2 of them for the next upgrades.

Old way:

uname -r
rpm -q kernel
rpm -e the-old-kernel    #example : rpm -e kernel-2.6.32-279.el6.x86_64
yum update
#check if the new kernel is there:
cat /boot/grub/grub.conf
shutdown -r now

Install FTP server (vsftpd) for Ubuntu:

sudo apt-get install vsftpd
nano /etc/vsftpd.conf
#uncomment the follwoing:
sudo service vsftpd restart

Install Webmin For Ubuntu:

sudo apt-get install perl libnet-ssleay-perl openssl libauthen-pam-perl libpam-runtime libio-pty-perl apt-show-versions python
sudo dpkg -i webmin_1.650_all.deb
#access it via web browser 
#For some reasons webmin won't auto start after reboot you need to run this command to get it working again:
sudo /etc/init.d/webmin start

Install or upgrade Openssl on Centos (Compile from source):

tar xvfz openssl-1.0.0k.tar.gz
cd openssl-1.0.0k 
make clean
./config shared –prefix=/usr –openssldir=/usr/local/openssl
make && make test
make install

Install or upgrade Openssl on Centos via yum:

sudo rpm -ivh --nosignature
yum --enablerepo=axivo update openssl
# or
yum --enablerepo=axivo install openssl

Uninstall a library in Linux opposite of make install:

make clean
make uninstall

Find if package is installed on Centos for example (openssl):

su -c 'yum list openssl'
rpm -qa | grep openssl

Instal apache + php + SSL on Debian and Ubuntu:

sudo apt-get install apache2 php5 openssl ssl-cert 
sudo a2ensite default-ssl
sudo a2enmod ssl
sudo service apache2 restart

Install liver-helper on Debian system to create fresh live image:

nano /etc/apt/sources.list
# Add the following
deb wheezy-snapshots main contrib non-free
deb-src wheezy-snapshots main contrib non-free

apt-get update
apt-get install live-build
mkdir /root/my-livecd
cd /root/my-livecd
lb clean
lb config --interactive shell   # To disable interactive shell use lb config --interactive disabled
lb build
# A file called  binary-hybrid.iso will be on same folder

Create live image from current installation on Debian or Ubuntu:

wget -O - | apt-key add -
nano /etc/apt/sources.list
# Add the following:
deb wheezy main
deb-src wheezy main
# For Ubuntu use the following:
deb precise main
deb quantal main

sudo apt-get update
sudo apt-get install remastersys

# Usage sudo remastersys backup|clean|dist [cdfs|iso] [filename.iso]
# Config global settings
nano /etc/remastersys.conf
# To make a livecd/dvd backup and call the iso custom.iso with user personal folders:
sudo remastersys backup Debian-live-custom.iso 
# or 
sudo remastersys backup Ubuntu-live-custom.iso 

# To clean up temporary files of remastersys
sudo remastersys clean

To make a livecd/dvd backup and call the iso custom.iso without user personal folders:
sudo remastersys dist custom.iso

# To make a distributable livecd/dvd filesystem only
sudo remastersys dist cdfs

How to install ConfigServer ModSecurity Control:

tar -xzf cmc.tgz
cd cmc/

How to install Commodo Web Application Firewall:
First you will need access from here.


To add to Commodo Web Application Firewall Cpanel ModSecurity™ Vendors you need to imort the following file:

To check all ModSecurity™ Vendors installed by Cpanel:

cat /var/cpanel/modsec_cpanel_conf_datastore

If apache won’t start due errors on CWAF rules run the following:

/usr/local/cpanel/scripts/modsec_vendor update --auto

or if problem is not fixed:

rm -rf /var/cpanel/cwaf/rules/*

After upgrading WHM Perl gets updated and CWAF won’t start throwing the following error:
No response from subprocess (/usr/local/cpanel/whostmgr/docroot/cgi/addon_cwaf.cgi): The subprocess reported error number 2 when it ended.
To solve it:

cp -avr /var/cpanel/cwaf/modules/CPAN/lib/* /usr/local/cpanel/3rdparty/perl/522/lib64/perl5/cpanel_lib

Install FFmpeg on CentOS:

nano /etc/yum.repos.d/atrpms.repo
# paste the following:
name=Fedora Core $releasever - $basearch - ATrpms

# Then run:
yum update
yum install ffmpeg

# To check the version:
ffmpeg -version

To install Elasticsearch on CentOS:

cd ~
sudo yum update
su -c "yum install java-1.8.0-openjdk"

rm -f
mv elasticsearch-* elasticsearch 
sudo mv elasticsearch /usr/local/share

curl -L | tar -xz
mv *servicewrapper*/service /usr/local/share/elasticsearch/bin/
rm -Rf *servicewrapper*
sudo /usr/local/share/elasticsearch/bin/service/elasticsearch install
sudo /etc/init.d/elasticsearch start

# To test
curl http://localhost:9200 

To check how many records have been stored to elasticsearch’s search index:

curl -XGET 'http://localhost:9200/wcf/com_woltlab_wbb_post/_count?q=*'

To install ImageMagick:

yum install ImageMagick

To install RED5 server on a Debian node:

apt-get update
apt-get install red5-server
service red5-server start

# Ports that should be opened by now:
RTMP: 1935
Debug proxy: 1936
HTTP servlet: 5080
RTMPT: 8088

# Navigate to verify its there

# Install Cometchat Whiteboard plugin
cd /usr/share/red5/webapps
tar -xzf ccred5whiteboard.tar.gz
mv ccred5whiteboard.tar.gz ccred5whiteboard.tar
tar xvf ccred5whiteboard.tar

# Install Cometchat Screenshare plugin
tar -xzf ccred5screenshare.tar.gz
mv ccred5screenshare.tar.gz ccred5screenshare.tar
tar xvf ccred5screenshare.tar

rm -f ccred5whiteboard.tar
rm -f ccred5screenshare.tar

service red5-server restart

To disable ApacheBooster:

/scripts/manage_apacheboooster --disable

To enable ApacheBooster:

/scripts/manage_apacheboooster --enable

To update ApacheBooster:


To install Let’s Encrypt plugin for SSL certificates and enable it on WHM Cpanel:


To disable and uninstall the Let’s Encrypt plugin, run the following command:




Resources Monitor

Server resources like CPU and Memory some times are overloaded trace the reason:

top -c
ps -eo pcpu,pid,user,args | sort -k1 -r | head -10
ps aux | grep php

If you have prm installed usage:

prm -t 
prm -s

For Apache Web server resources you can use:

yum install apachetop
apachetop -f /var/log/apache2/access_log

To run shell script or php script on the background:

# First make sure /var/run/screen has mode 775:
chmod 775 /var/run/screen

# Then to run php script on background:
screen php searchindex.php   #or just type screen then Enter and type your command

# To view the list of all screen processes:
screen -ls

# To detach the screen:
CTRL+A followed by d 

# Or
screen -d SCREENID

# To attach the screen at anytime:
screen -r SCREENID

# To kill the screen
screen -X -S SCREENID quit

# Example:
screen -X -S 17285.pts-1.british quit

To Avoid CTRL D from logging off the user while using screen:


Here is another way but for my self I prefer screen:

# press Ctrl+Z to suspend the program
# list the current jobs    
# resume the job that's next in the queue
# resume job [number]
fg %[number] 
# Push the next job in the queue into the background
# Push the job [number] into the background
bg %[number]
# Kill the job numbered [number]   
kill %[number] 
# Send the signal [signal] to job number [number] 
kill -[signal] %[number] 
# disown the process(no more terminal will be owner), so command will be alive even after closing the terminal.
disown %[number] 

Or you can use nohup:

nohup ./yourscript &

# Send output to a file the nohup command does not automatically put the command in background. This must be done explicitly with &.
nohup date > date.log &

How to install Sar (Sysstat) Performance Monitoring in Debian:

sudo apt-get install sysstat

# Set Enabled to ture
nano /etc/default/sysstat

# Set interval from every 10 minutes to every 2 minutes.
nano /etc/cron.d/sysstat

# Change
5-55/10 * * * * root command -v debian-sa1 > /dev/null && debian-sa1 1 1
# To
*/2 * * * * root command -v debian-sa1 > /dev/null && debian-sa1 1 1

# Restart the service
service sysstat restart

# Usage Examples

# System CPU statistics 3 times (with 1 second interval)
sar 1 3

# Reports run queue and load average (sar -q)
sar -q
sar -q 1 3

# Overall I/O Activities (sar -b)
sar -b 1 3

# Individual Block Device I/O Activities (sar -d)
sar -d 1 1

#Report network statistics (sar -n)
sar -n ALL
sar -n DEV
sar -n IP

# CPU Usage of ALL CPUs (sar -u)
sar -u 
sar -u  ALL

# Memory Free and Used (sar -r)
sar -r 1 3

# CPU Usage of Individual CPU or Core (sar -P)
sar -P ALL 1 1

# Swap Space Used (sar -S)
sar -S 1 3

# Display context switch per second (sar -w)
sar -w 1 3

#  Report Sar Data Using Start Time (sar -s)
sar -s




Monitor server logs:

tail -f /var/log/messages

For example only get logs related to digi77

tail -f /var/log/messages | grep digi77

Apache logs on Centos located in /etc/httpd/logs:

tail -f /etc/httpd/logs/error_log
tail -f /etc/httpd/logs/access_log

Combine Apache and server logs:

tail -f /usr/local/apache/logs/error_log and tail -f /var/log/messages

Monitor all files downloads exe from digi77:

grep CustomLog /etc/httpd/conf/httpd.conf
tail -f /usr/local/apache/domlogs/ |grep .exe

Exclude the word “file does” example:

tail -f /etc/httpd/logs/error_log |grep -i -v "file does"

To disable logs in Apache comment (ErrorLog “logs/error_log” ) in the httpd configuration file and restart Apache.

locate -s httpd.conf

If you have space problems because of Apache logs:

for i in /usr/local/apache/logs/* ; do cat /dev/null > $i ; done
for i in /usr/local/apache/domlogs/* ; do cat /dev/null > $i ; done
rm -f /usr/local/apache/logs/archive/*.gz
rm -f -r /usr/local/apache.backup  
rm -f -r /usr/local/apache.backup_archive

Apache logs on Ubuntu:

tail -f /var/log/apache2/error.log

To prevent and stop the logs on CentOS box:

#login to the box
cat > /var/log/lastlog
cat > /var/log/utmp
cat > /var/log/wtmp
cat > /var/log/secure
# Type your commands

To find and shred all server logs (Be careful):

find /var/log -type f | xargs shred -v --remove

For my sql logs you have to change the config file:

locate -s my.cnf
nano /etc/my.cnf

Then add this to it:


Then you need to create some files:

mkdir /var/log/mysql
touch /var/log/mysql/log-slow-queries.log
chown mysql.mysql -R /var/log/mysql
touch /var/log/mysql/errors.log
chown mysql.mysql -R /var/log/mysql

Now you are ready to view the logs:

tail -f /var/log/mysql/log-slow-queries.log
tail -f /var/log/mysql/log-slow-queries.log and /var/log/mysql/errors.log

To find list huge files +1G in general:

 find . -size +1G -printf '%s %p\n' 

To find list huge error_log – over 50 MB – files along with the size they occupy:

find /home/*/public_html/ -type f -iname error_log -size +50M -exec du -sh {} \;

To find list and DELETE! huge error_log – over 50 MB – files:

find /home/*/public_html/ -type f -iname error_log -size +50M -exec rm -f {} \;






Repair Mysql tables:

myisamchk -r -t=/home/oman0/tmp *.MYI     
myisamchk -m *.MYI
myisamchk -e *.MYI
myisamchk -e -r post.MYI
myisamchk -e -o post.MYI
myisamchk -A --auto-repair post.MYI

Or use:

use tabe_name:
repair table pm;
repair table pmreceipt;
repair table pmtext;
repair table post;

Rebuild Apache config file:


Repair Apache config file:

/usr/local/cpanel/bin/apache_conf_distiller --update

If you face a problem with yum on VPS node:

nano  /etc/yum/pluginconf.d/fastestmirror.conf
#set "enable=0"

Fix Easyapache Timeout on connect:

nano /etc/hosts
#File should look like this               localhost.localdomain localhost saver

#or               localhost localhost4 localhost4.localdomain4
::1             localhost localhost6 localhost6.localdomain6 master

/scripts/easyapache --build

Fix FastCGI Data Timeout Error (mod_fcgid read data timeout in 40 seconds):

nano /usr/local/apache/conf/includes/post_virtualhost_global.conf
#Add to the end of the file the following:
<IfModule mod_fcgid.c>
 FcgidProcessLifeTime 8200
 FcgidIOTimeout 8200
 FcgidConnectTimeout 400
 FcgidMaxRequestLen 1000000000

If Openssl causes errors while updating CENTOS update or upgrade use the following command:

yum update --exclude openssl* --skip-broken

If you can’t restore a user from Cpanel backup and you get one of this error messages:

“Cannot restore. That user already exists on this system”
“Sorry, a passwd entry for that username already exists”

/scripts/restorepkg --force username
#for example user oman0
/scripts/restorepkg --force oman0

If Apache troughs the following error:
“SecurityException in Application.cpp:188: Do not have root privileges. Executable not set-uid root?”

chmod +s /opt/suphp/sbin/suphp

Bash script to remove cpmove.psql folders from cPanel home user accounts:

# Write a short script

# Paste the below 
for user in `ls -A /var/cpanel/users`
    rm -rf /home/$user/cpmove.psql*

# Run th script

# Delete it
rm -f

If a package is causing error when running yum command for example OpenSSL you have to exclude it as the following:

nano /etc/yum.conf
# Then 
exclude=bind-chroot courier* dovecot* exim* filesystem httpd* mod_ssl* mydns* mysql* nsd* php* proftpd* pure-ftpd* ruby* spamassassin* squirrelmail* openssl*

Fix RPM Installation via WHM/Cpanel:

/usr/local/cpanel/scripts/check_cpanel_rpms --fix

To rebuild the RPM database via:

yum clear all
mkdir /root/old_rpm_dbs/
mv /var/lib/rpm/__db* /root/old_rpm_dbs/
rpm --rebuilddb

To clean up yum:

su -c 'yum clean headers'
su -c 'yum clean packages'
su -c 'yum clean metadata'

If one of the yum sources fails you will have to disable it:
Example “ [Errno 14] PYCURL ERROR 7 – “couldn’t connect to host”

cd /etc/yum.repos.d/
nano atrpms.repo
# Now set enable from 1 to 0
yum update

Remove package without the dependencies:
rpm -e --nodeps packakgename

Some times when you run a bash script via corn job you get the following error “sudo: sorry, you must have a tty to run sudo” to solve it use the following:

nano /etc/sudoers
# Repalce Defaults  requiretty with:
Defaults   !requiretty

Apache2 Configuration Files Location on Debian:

nano /etc/apache2/apache2.conf
# listening ports
nano /etc/apache2/ports.conf

Some times system gives you error of permission denied to .htaccess file an error message that would look like this: “Permission denied: /var/www/abc/.htaccess pcfg_openfile: unable to check htaccess file” or “Server unable to read htaccess file, denying access to be safe”

To solve it do the following:

chmod 755 Direcroty_contaning_.htacess -R
cd Direcroty_contaning_.htacess
chmod 644 .htaccess

Other issue might occur when trying to protect a directory with a password where WordPress would always show you page not found error all you have to do is add the following on WordPress .htaccess:

ErrorDocument 401 default



Tweaks and Information

Get PHP version:

php -v

Get Mysql version:

mysql -v

Get Apache version:

httpd -v

Get Openssl version:

openssl version

Get php config file location:

php --ini

Get installed php modules:

php -m

Protecting upload folder:

chmod -R 775 uploads

Set write permission to a file:

chmod -R 0755 fp.php

To switch to the new user with users profile and variables:

su - username

To continue with the current profile and variables:

su username

Ask CalmAv to scan home for viruses then output results to a file:

clamscan -r --bell -i /home/ > /home/digi77/www/v.txt

To change Linux default Editor:

export EDITOR=pico
export EDITOR=vi
export EDITOR=nano


export VISUAL=vi
export VISUAL=pico
export EDITOR=nano

To change file modification date:

touch -d '5 May 2013 10:22' sendmessage.php

To change the owner of a file or folder:

chown oman0.oman0 public_html/ -R

Change SSH port number:

nano /etc/ssh/sshd_config
sudo /etc/init.d/ssh restart

If SSH is stuck and you can’t connect:

rm /etc/ssh/ssh_host_*
dpkg-reconfigure openssh-server
#Update client side hosts:
~/.ssh/known_hosts files

Change Ftp port number:

nano /etc/pure-ftpd.conf

To search in nano editor:


Copy file and replace original with no prompt:

yes | cp sendmessage.php /home/digi77/forum/

To edit cron jobs:

crontab -e

To list them:

crontab -l

Execute a cron job every 5 Minutes

*/5 * * * * bash /root/  > /var/www/myfile.html

Execute a cron job every 5 Days

0 0 */5 * * bash /root/  > /var/www/myfile.html

Cron job simplification:

+---------------- minute (0 - 59)
 |  +------------- hour (0 - 23)
 |  |  +---------- day of month (1 - 31)
 |  |  |  +------- month (1 - 12)
 |  |  |  |  +---- day of week (0 - 6) (Sunday=0 or 7)
 |  |  |  |  |
 *  *  *  *  *  command to be executed

To view day of the week:

echo $(( $(date -d "$1" +%w ) + 1 ))

To delete files older than a year:

find /home/digi77/www/uploads/  -name '*.*' -mtime +360 -exec rm {} \;

To delete files older than 2 days:

ls -t | sed -e '1,2d' |xargs rm

To check disk health and folder sizes:

du -h --max-depth=1

View folder size in summary for MG:

du -s -m /home/digi77

Kill a process by its name (example process name is: cxs):

kill -9 `ps -ef | grep cxs | grep -v grep | awk '{print $2}'`

To extract .rar compressed files:

yum install rar unrar
unrar x -kb

To compress and add folder to .tar and .gz file:

tar -cf thefile.tar /home 
gzip -1 thefile.tar

To compress and add folder to tar then auto gzip it -z for backups:

tar -zcf theBackupFileofDigi77.tar /home/digi77

To extract from zip file:


To extract from password protected zip file:

sudo unzip -P the_Password

To add to zip file;

zip -r thesourc.wav

Add the file to the same folder as in the original directory hierarchy:

zip -g xxx.mp3 folder/file

To extract from tar or .gz file:

tar -xvf thefile.tar
gunzip -c thefile.tar.gz | tar xvf

How to install 7zip on Linux Centos:

rpm --import
Check machine architecture: uname -i
rpm -K rpmforge-release-0.5.3-1.el6.rf.x86_64.rpm
rpm -i rpmforge-release-0.5.3-1.el6.rf.x86_64.rpm
yum -y install p7zip

On Debian or Ubuntu:

sudo apt-get install p7zip-full

To create an encrypted zip file with 7z archiver:

7za a -tzip -pMY_SECRET -mem=AES256 doc.pdf doc2.pdf doc3.pdf 

To uncompress a zip file that is encrypted with 7za command:

7za e 

To extract a password protected file on CentOS:

7za x -pThePassword

To extract a password protected file on Debian:

7z x -pThePassword

To set root email foward:


To prevent Cpanel from restarting Apache and other services:

nano /etc/chkserv.d/chkservd.conf

Display list of updated software centOS:

yum list updates

Updaye centOS:

yum update

Find out if httpd package is installed or not:

rpm -qa | grep httpd*
yum list installed httpd

Update package httpd:

yum update httpd

Add Apache httpd to system start-up:

chkconfig httpd --add
chkconfig  httpd  on --level 2,3,5

Check if on the list:

chkconfig --list httpd

Remove from the list:

chkconfig httpd off
chkconfig httpd --del

Or use:

sudo apt-get install sysv-rc-conf

Let apache2 start with OS boot Ubuntu:

sudo update-rc.d -f apache2 remove
update-rc.d apache2 defaults
service apache2 stop
service apache2 start

Restart a service like ssh:

sudo service ssh restart
sudo /etc/init.d/ssh restart

Clear temporary blocked ips from CSF firewall:

perl /etc/csf/ -tf
# or
csf -tf

Clear permanent blocked ips from CSF firewall:

perl /etc/csf/ -df
# or
csf -df

Disable CSF firewall:

csf -x
# or enable it by:
csf -e

Restart CSF firewall:

perl /etc/csf/ -r

FTP Passive Mode blocked by CSF firewall:

# PureFTPd
nano /etc/pure-ftpd.conf
#Set PassivePortRange    32000 33000

# ProFTPd
nano /etc/pure-ftpd.conf
# Set PassivePorts    32000 33000
# Change CSF settings TCP_IN: 20,21,22,25,53,80,110,143,443,32000:33000
# Restart FTP + Restart CSF

Directory permission reference:

755 -- **ALL** Folders (Including those that script authors tell you to set 777)
644 -- Non Script Files (Images, Basic HTML, Templates, Etc)
600 -- PHP Scripts (*.php, *.php4, *.php5)
755 -- CGI and Shell Scripts (*.cgi, *.pl, *.pm, *.py, *.e, *.sh)
400 -- RARE When PHP scripts **DON'T** want to be writable
755 -- RARE PHP Scripts used under CLI as a shell script

Allow TLS via FTP (Proftp – Ubuntu ) and restrict access via TLS only:

mkdir /etc/proftpd/ssl
openssl req -new -x509 -days 180 -nodes -out /etc/proftpd/ssl/ftp.cert.pem -keyout /etc/proftpd/ssl/ftp.key.pem

#uncomment the following from the file  /etc/proftpd/proftpd.conf
nano  /etc/proftpd/proftpd.conf
#include /etc/proftpd/tls.conf

#add the follwing at the end of the file just before  </IfModule>

TLSEngine on
TLSLog /var/log/proftpd/tls.log
TLSProtocol SSLv23
TLSOptions NoCertRequest
TLSRSACertificateFile /etc/proftpd/ssl/ftp.cert.pem
TLSRSACertificateKeyFile /etc/proftpd/ssl/ftp.key.pem
TLSVerifyClient off
TLSRequired on

/etc/init.d/proftpd restart

Prevent script from running twice:


  # Wait for lock on /var/lock/.myscript.exclusivelock (fd 200) for 10 seconds
  flock -x -w 10 200 || exit 1

  # Do stuff
  cd /home
) 200>/var/lock/.myscript.exclusivelock

To know how long (execution time) your shell script took to execute:

start=$(date +%s.%N)


end=$(date +%s.%N)    
runtime=$(python -c "print ${end} - ${start}")

echo "Runtime was $runtime"

Compress http output using DEFLATE – gzip:

nano /usr/local/apache/conf/includes/post_virtualhost_global.conf
#Add to the end of the file the following:
AddOutputFilterByType DEFLATE text/plain
AddOutputFilterByType DEFLATE text/xml
AddOutputFilterByType DEFLATE application/xhtml+xml
AddOutputFilterByType DEFLATE text/css
AddOutputFilterByType DEFLATE application/xml
AddOutputFilterByType DEFLATE image/svg+xml
AddOutputFilterByType DEFLATE application/rss+xml
AddOutputFilterByType DEFLATE application/atom_xml
AddOutputFilterByType DEFLATE application/x-javascript
AddOutputFilterByType DEFLATE application/x-httpd-php
AddOutputFilterByType DEFLATE application/x-httpd-fastphp
AddOutputFilterByType DEFLATE application/x-httpd-eruby
AddOutputFilterByType DEFLATE text/html
SetOutputFilter DEFLATE
SetEnvIfNoCase Request_URI \.(?:gif|jpe?g|png)$ no-gzip dont-vary
SetEnvIfNoCase Request_URI \.(?:exe|t?gz|zip|bz2|sit|rar)$ no-gzip dont-vary
SetEnvIfNoCase Request_URI \.pdf$ no-gzip dont-vary
SetEnvIfNoCase Request_URI \.avi$ no-gzip dont-vary
SetEnvIfNoCase Request_URI \.mov$ no-gzip dont-vary
SetEnvIfNoCase Request_URI \.mp3$ no-gzip dont-vary
SetEnvIfNoCase Request_URI \.mp4$ no-gzip dont-vary
SetEnvIfNoCase Request_URI \.rm$ no-gzip dont-vary
BrowserMatch ^Mozilla/4 gzip-only-text/html
BrowserMatch ^Mozilla/4\.0[678] no-gzip
BrowserMatch \bMSI[E] !no-gzip !gzip-only-text/html
Header append Vary User-Agent env=!dont-vary

Get Ip from file .eeds-xxxx:

cat .eeds-xxxx|cut -d : -f 1}

Get process age for openvpn:

ps -eo pid,command,etime|grep 'openvpn --daemon --config'|cut -d / -f 2|sed 's/^ *//;s/ *$//'

Get Status from file in this format ip:status:country ->[secure]:USA

cat .eeds-ipinfo|cut -d : -f 2|cut -d [ -f 2|cut -d ] -f 1

Get country from file in this format ip:status:country ->[secure]:USA

geoiplookup `cat .eeds-xxxx|cut -d : -f 1`|cut -d : -f 2|cut -d , -f 2|sed 's/^ *//;s/ *$//'

Get Tor Ip then send to file:

curl --proxy socks5h://localhost:9050 -s -m 30 > .eeds-xxx

Get Dns Info from resolv.conf:

cat /etc/resolv.conf |grep Dnsused|cut -d : -f 2
cat /etc/resolv.conf |grep nameserver|cut -d r -f 3|sed 's/^ *//;s/ *$//'| awk 'NR==1'
cat /etc/resolv.conf |grep nameserver|cut -d r -f 3|sed 's/^ *//;s/ *$//'| awk 'NR==2'

In Debian in order to allow x86 32-bit applications to work on 64-bit OS installation:

sudo dpkg --add-architecture i386
sudo apt-get update    

Delete GPA default expired keys on Debian:

truncate -s 0 ~/.gnupg/pubring.kbx

To check if your processors are 32-bit or 64-bit :

getconf LONG_BIT 

To know the graphic card driver that is being used (VGA):

lspci |grep VGA

Change node time to GMT+4 Oman time:

cd /etc
ln -sf /usr/share/zoneinfo/Asia/Muscat localtime

Change node time to GMT+4 Moscow time:

rm /etc/localtime
cd /etc
ln -s /usr/share/zoneinfo/Europe/Moscow localtime

Or in Debian use:

sudo dpkg-reconfigure tzdata

Use ‘rdate’ or ‘ntpdate’ to synchronize your server time with reference time. Make sure your firewall allows it or switch it off temporary csf -x

service ntpd stop
service ntpd start

Set php time zone to GMT+4 – Debian:

php --ini
nano /etc/php5/cli/php.ini
date.timezone ="Asia/Muscat"

Disable script watch for cpanel:

/usr/local/cpanel/bin/tailwatchd --disable=Cpanel::TailWatch::ChkServd

Enable script watch for cpanel

/usr/local/cpanel/bin/tailwatchd --enable=Cpanel::TailWatch::ChkServd

Enable all monitoring services for Cpanel:

whmapi1 enable_monitor_all_enabled_services 

Get md5 of a file or list of files:

md5sum *.tar

Count number of lines in file:

wc -l myfile
#Use the following to get the number only
cat myfile |wc -l

Check if file /etc/passwd exists or not:

[ -f /etc/passwd ] && echo "File exists" || echo "File does not exists"

Check if file /etc/passwd exists or not on shell script:

if [ -f $FILE ];
   echo "File $FILE does exists"
   echo "File $FILE does not exists"

Redirect your Webserver home page from HTTPS to HTTP

RewriteCond %{HTTPS} on
RewriteCond %{REQUEST_URI}   !^/(.*)\.(css|png|js|jpe?g|gif|bmp)$
RewriteRule ^$ http://%{HTTP_HOST} [L,R]

Redirect your Webserver home page from HTTP to HTTPS

RewriteEngine on
RewriteCond %{HTTPS} off
RewriteRule ^(.*)$ https://%{HTTP_HOST}/$1 [R=301,L]

Email list clean up – Read a file Line By Line and check if the email is not valid and output to text file:

while read line; do sendmail -bv "$line"; done < emails.txt |grep failed > invalidemails.txt

Now you can grep all email addresses from a Text File using regular expressions:

grep -E -o "\b[a-zA-Z0-9.-]+@[a-zA-Z0-9.-]+\.[a-zA-Z0-9.-]+\b" invalidemails.txt > invalidemails2.txt

Find PHP root path of the current folder useful for installations:


List directory and file structure:

tree -d /path






To Get your remote IP:

echo $SSH_CLIENT | awk '{ print $1}'

Get your local ip from eth0:

/sbin/ifconfig eth0 | grep "inet addr" | awk -F: '{print $2}' | awk '{print $1}'

Function to get your local IP:

function int-ip { /sbin/ifconfig $1 | grep "inet addr" | awk -F: '{print $2}' | awk '{print $1}'; }
IP_ADDR=$(int-ip eth0)

Function to get your local IP and allow traffic forwarding:

function int-ip { /sbin/ifconfig $1 | grep "inet addr" | awk -F: '{print $2}' |$
IP_ADDR=$(int-ip eth0)
iptables -t nat -A POSTROUTING -o eth0 -j SNAT --to $IP_ADDR
echo 1 > /proc/sys/net/ipv4/ip_forward

Resolve domain name to ip number:

sudo apt-get install dnsutils
dig +short | awk 'NR==1'

Extract ips from a file:

grep -o '[0-9]\{1,3\}\.[0-9]\{1,3\}\.[0-9]\{1,3\}\.[0-9]\{1,3\}' pentest.txt |sort -n|uniq -u

Commands you need to change ip address or configure your network cards on Centos:

nano /etc/sysconfig/network
nano /etc/resolv.conf
nano /etc/hosts
nano /etc/sysconfig/network-scripts/ifcfg-eth0
service network restart

Get connections per port number:

netstat -tuna | awk -F':+| +' 'NR>2{print $5}' | cut -d: -f1 | sort | uniq -c | sort -n

Get connections per IP number (useful if you are facing DDOS attack):

netstat -ntu | awk -F"[ :]+" 'NR>2{print $6}'|sort|uniq -c|sort -nr
netstat -ntu | awk '{print $5}' | cut -d: -f1 | sort | uniq -c | sort -n
netstat -ntu | tail -n +3 | awk '{print $5}' | cut -d: -f1 | sort | uniq -c | sort -n

Find applications with ports that they are using TCP:

netstat -tlnp

Find applications with ports that they are using TCP UDP:

lsof -i -P

Kill an application by the port its using (Example port: 51128) :

kill -9 $(sudo netstat -anp | grep :51128 | awk '{print $7}' | cut -d '/' -f 1)

Installing and Configuring ufw (Uncomplicated Firewall) first, ufw needs to be enabled:

sudo apt-get install ufw
sudo ufw enable

To see the firewall status, enter:

sudo ufw status

To change default profile so it accepts all incoming and outgoing traffic:

sudo ufw status verbose
sudo ufw default allow incoming
sudo ufw reset
sudo ufw enable

To allow ufw to forward VPN traffic:

nano /etc/default/ufw
# Set 

Similarly, to close an opened port:

sudo ufw deny 22
sudo ufw deny 80/tcp

To remove a rule, use delete followed by the rule:

sudo ufw delete deny 22

Allow specific ports:

sudo ufw allow ssh
sudo ufw allow 22/tcp
sudo ufw allow www or sudo ufw allow 80/tcp
sudo ufw allow ftp or sudo ufw allow 21/tcp 

It is also possible to allow access from specific hosts or networks to a port. The following example allows ssh access from host to any ip address on this host:

sudo ufw allow proto tcp from to any port 22
sudo ufw allow proto tcp from to port 42121
sudo ufw allow from   # Alow all ports from

Adding the –dry-run option to a ufw command will output the resulting rules, but not apply them. For example, the following is what would be applied if opening the HTTP port:

sudo ufw --dry-run allow http

To allow ports 1000 through 2000, use the command:

sudo ufw allow 1000:2000/tcp

ufw can be disabled by:

sudo ufw disable

To view the numbered format:

sudo ufw status numbered

Delete specific number:

sudo ufw delete 3

Reset Everything:

sudo ufw reset

Block IP address in Iptables:

sudo iptables -I INPUT -s -j DROP

UnBlock IP address in Iptables:

sudo iptables -D INPUT -s -j DROP

Flush All Chains:

sudo iptables -F

Determine a rule’s line number :

sudo iptables -L --line-numbers
sudo iptables -L --line-numbers|grep 24.2x3.1x9.2xx    # with specific ip

Delete Rule by Chain and Number:

sudo iptables -D INPUT 7

List Rules as Tables:

sudo iptables -L
sudo iptables -L|grep  24.2x3.1x9.2xx    # with specific ip 

Set static ip on Centos:

nano /etc/sysconfig/network
#Sample static ip configuration should look like this

NETWORKING=yes # set ur own
GATEWAY= # set ur own

nano /etc/sysconfig/network-scripts/ifcfg-eth0
#Sample static ip configuration should look like this

# Intel Corporation 82573E Gigabit Ethernet Controller (Copper)
BOOTPROTO=static # for dynamic ip set this to dhcp
IPADDR=       # set ur own
NETMASK= # set ur own
nano /etc/resolv.conf
#Sample static ip configuration should look like this

nameserver # set ur own dns ips
nameserver # set ur own dns ips

/etc/init.d/network restart
serivec network restart
#To verify new static ip configuration for eth0, enter:
ifconfig eth0
route -n

Get network drivers support for Debian live cd and make it connect on boot:

cd /root
rm -f firmware-b43-installer_015-14.1_all.deb
rm -f firmware-b43legacy-installer_015-14.1_all.deb
rm -f amd64-microcode_1.20120910-2_i386.deb
rm -f intel-microcode_1.20130222.1_i386.deb
rm -f ixp4xx-microcode_2.4-3_armel.deb
rm -f prism2-usb-firmware-installer_0.2.9+dfsg-5_armel.deb
rm -f prism2-usb-firmware-installer_0.2.9+dfsg-5_armhf.deb
rm -f prism2-usb-firmware-installer_0.2.9+dfsg-5_i386.deb
rm -f prism2-usb-firmware-installer_0.2.9+dfsg-5_powerpc.deb
rm -f firmware-b43-lpphy-installer_015-14.1_all.deb
dpkg -i *.deb

rm -f *.deb
rm -f

nano /etc/network/interfaces
# Add the following before any command avoid any duplicates:

# The loopback network interface
auto lo
iface lo inet loopback

# The primary network interface
allow-hotplug eth0
iface eth0 inet dhcp

allow-hotplug eth1
iface eth1 inet dhcp

allow-hotplug eth2
iface eth2 inet dhcp

allow-hotplug eth3
iface eth3 inet dhcp

# To test
/etc/init.d/networking restart

# Or ge the drivers from non free Debian Source
sudo nano /etc/apt/sources.list
deb stable main contrib non-free

sudo apt-get update
sudo apt-get install firmware-b43legacy-installer firmware-brcm80211 firmware-ivtv firmware-linux-free firmware-qlogic firmware-adi firmware-crystalhd firmware-iwlwifi firmware-linux-nonfree firmware-ralink firmware-atheros firmware-bnx2 firmware-intelwimax firmware-libertas firmware-myricom firmware-realtek firmware-b43-installer firmware-bnx2x firmware-ipw2x00 firmware-linux firmware-netxen

To forward all incoming traffic to on port 80 and redirect it to remote website on port 443:

sudo apt-get install socat
socat TCP4-LISTEN:80,fork

# or use redir if local ip is then forward all port 80 and 8080 traffic to on port 443

redir --laddr= --lport=80 --cport=443|redir --laddr= --lport=8080 --cport=443

# Or use iptables:

sudo sysctl net.ipv4.ip_forward=1
sudo iptables -t nat -A PREROUTING -p tcp --dport 80 -j DNAT --to-destination
sudo iptables -t nat -A POSTROUTING -j MASQUERADE  

Add bash file to allow incoming traffic to be forwarded to the internet mostly used for vpn connections:

iptables -t nat -A POSTROUTING -o venet0 -j SNAT --to    # Sometimes change venet0 to eth0 change the ip as well
echo 1 > /proc/sys/net/ipv4/ip_forward

More tips on port forwarding see here.

To monitor your bandwidth usage you can use tools such as iftop and vnstat:

To install:

 sudo apt-get install iftop
 sudo apt-get install vnstat

Iftop usage:

# Sort by 40s column display port and hide hostname:
iftop -n -o 40s -P

vnstat usage (You can swap eth0 with venet0):

vnstat -i eth0 -h               # -h Hourly  -d Daily  -m Monthly
vnstat -i eth0 -d								
vnstat -i eth0 -m               

To block bit torrent traffic on vps node using iptables ( Uncomment the the rest if you only need them ):

iptables -N LOGDROP > /dev/null 2> /dev/null
iptables -F LOGDROP
iptables -A LOGDROP -j LOG --log-prefix "LOGDROP "
iptables -A LOGDROP -j DROP
#iptables -A FORWARD -m string --algo bm --string "BitTorrent" -j LOGDROP
iptables -A FORWARD -m string --algo bm --string "BitTorrent protocol" -j LOGDROP
#iptables -A FORWARD -m string --algo bm --string "peer_id=" -j LOGDROP
#iptables -A FORWARD -m string --algo bm --string ".torrent" -j LOGDROP
#iptables -A FORWARD -m string --algo bm --string "announce.php?passkey=" -j LOGDROP
#iptables -A FORWARD -m string --algo bm --string "torrent" -j LOGDROP
#iptables -A FORWARD -m string --algo bm --string "announce" -j LOGDROP
#iptables -A FORWARD -m string --algo bm --string "info_hash" -j LOGDROP
#iptables -A FORWARD -m string --string "get_peers" --algo bm -j LOGDROP
#iptables -A FORWARD -m string --string "announce_peer" --algo bm -j LOGDROP
#iptables -A FORWARD -m string --string "find_node" --algo bm -j LOGDROP

Change webserver apache port number:

nano /etc/apache2/ports.conf
Listen 8010

To have apache listen on two ports:

Listen 80
Listen 8010

To make the apache server accept connections on two specified interfaces and port numbers, enter:


To check if the remote node is blocking any given port number:

nc -vv 21

To split a file into smaller chunks of 100MB:

split --bytes 100M --numeric-suffixes --suffix-length=3 thebigfile.sql split-file

Find the word userOption51 in every file on the directory and return only file names -l:

grep -rl userOption51

For accelerated download instead of wget use axle:

sudo apt-get install axel 
# Limit speed 
axel -s 5242880 
# Limit a number of connection
axel -n 3 -s 5242880 




Display connect time in hours:


Display list of last logged-in users:


Display list of bad last login attempts:


Display last time user logged in:


Display last command executed in reverse order:


Display currently logged in users:


Display who is logged in and what they are doing:


List Linux hidden users hunt for hackers:

cat /etc/passwd | grep /home | cut -d: -f1
cat /etc/passwd |grep 500* 
cat /etc/passwd
cat /etc/sudoers

Another method to hunt for shells:

find /home -name "*php*" -print | xargs grep -F 'base64_decode($_POST["qer"]).";"); ?'
find /home -name "*php*" -print | xargs grep -F 'c99sh'
find /home -name "*php*" -print | xargs grep -F 'owned by uid'
find /home -name "*php*" -print | xargs grep -F 'eval(gzinflate(base64_decode'

Add user fox with root privilige:

useradd -G root fox
passwd fox
id fox

Delete the user along with the home folder:

userdel -r fox

Get the root password:

head -10 /etc/shadow

Kick a user from ssh session:

ps aux | grep sshd
ps aux | grep pts/1
kill -9 26882

If your server is under DDOS attack on port 80 these commands are useful:

netstat -alpn | grep :80 | awk '{print $4}' | cut -d: -f1 | sort | uniq -c
netstat -anp |grep 'tcp\|udp' | awk '{print $5}' | cut -d: -f1 | sort | uniq -c | sort -n
netstat -tn 2>/dev/null | grep :80 | awk '{print $5}' | cut -f1 -d: | sort | uniq -c | sort -rn | head
netstat -s

Find who is using a specific port ex:8443 :

lsof -w -n -i tcp:8443
fuser -n tcp 8443 
netstat -anp|grep :8443[[:blank:]]

Clean user and mysql history:

cat > .bash_history
history -c
cat > /root/.mysql_history

Get email notification sent to you if ssh is accessed via root:

cd /root
nano .bashrc
echo 'ALERT - Root Shell Access (Your server Name) on:' `date` `who` | mail -s "Alert: Root Access from `who | cut -d'(' -f2 | cut -d')' -f1`"

Add ssh keys to server:

nano /root/.ssh/authorized_keys
nano /root/.ssh/authorized_keys2
# each key on single line

Disable root login if you have ssh keys set:

nano /etc/ssh/sshd_config
#Add the following after #PermitEmptyPasswords no:
PasswordAuthentication  no
sudo service ssh restart

Mitigating the Beast, Heartbleed, and POODLE attack on TLS on CentOS with this changes you will get grade A on sslabs detailed guide is here.

Disable file listing on your Webserver add this line to the beginning of .htaccess file:

Options All -Indexes

Deny Baidu from accessing your site via .htaccess

RewriteEngine On
RewriteCond %{HTTP_USER_AGENT} Baidu
RewriteRule ^.*$ [R,L]
BrowserMatchNoCase Baiduspider bad_bot
Deny from env=bad_bot

Protecting a directory with Apache and .htaccess:

htpasswd -c /etc/apache2/.htpasswd user1
htpasswd /etc/apache2/.htpasswd user2

Create a .htaccess file in the folder you wish to protect:

AuthType Basic
AuthUserFile /etc/apache2/.htpasswd
AuthName "Enter password"
Require valid-user

Shred all files in folder and sub folders:

find -type f -execdir shred -v -u '{}' \;
rm -rf *

To check for Bash ‘shell shock’ vulnerability:

env x='() { :;}; echo vulnerable' bash -c "echo this is a test"

If it says vulnerable then update your system immediately. A respond from patched system looks like this:

bash: warning: x: ignoring function definition attempt
bash: error importing function definition for `x'
this is a test

To generate new pgp – gpg keys on CentOS server:
# Make sure you choose a strong password with a key strength of 4096 bits


To view private keys:

gpg -K

To view public keys:

gpg -k

To Export private key:

gpg --armor --export-secret-keys > private-key.asc

To Export public key:

gpg --armor --export  > public-key.asc

More OpenPGP/GPG commands 1 , 2.

Hardening SSH server you will need to use Xshell or SecureCRT as SSH client:
Delete all host keys:

ls -l /etc/ssh/
rm -f /etc/ssh/ssh_host_*_key*
ls -l /etc/ssh/

Generate new RSA (4096) host key:
# Do not set a password

ssh-keygen -t rsa -b 4096 -f /etc/ssh/ssh_host_rsa_key          

You can import ssh_host_rsa_key to puttyGEN. Then export putty-public-key / putty-private-key / screen key to be pasted in /root/.ssh/authorized_keys )

nano /root/.ssh/authorized_keys

– Change Default port to a higher number 41221

nano /etc/ssh/sshd_config


Port 41221

– Comment dsa and ecdsa “HostKey”

#HostKey /etc/ssh/ssh_host_dsa_key
#HostKey /etc/ssh/ssh_host_ecdsa_key

– Change “PasswordAuthentication” to “no”

PasswordAuthentication no

– Paste the following to the end of the config file:

KexAlgorithms diffie-hellman-group-exchange-sha256
Ciphers aes256-ctr,aes192-ctr,aes128-ctr
MACs hmac-sha2-512,hmac-sha2-256,hmac-ripemd160     #Putty does not support hmac-sha2-512  
#New cent os will through error you need to use  the follwing to see what is supported:
ssh -Q mac
# Check ssh config for errors before restarting
sshd -t



Mail Exim

Check mail logs:

tail -f /var/log/exim_mainlog

Exim mail cleaner:

exiqgrep -i -o 172000 | xargs exim -Mrm
exim -bp - shows mail queue
exim -M emailID - force delivery of one message
exim -Mvl messageID - View Log for message
exim -Mvb messageID - View Body for message
exim -Mvh messageID - View Header for message
exim -Mrm messageID - ReMove message (no errors sent)
exiqgrep -zi | xargs exim -Mrm - Remove all frozen mails in q

Exim mail queue run:

exim -q -v

Exim mail counter:

exim -bpc

To change max load value of Exim mail:

first locate exim.conf
locate -s exim.conf
nano exim.conf
#change max load value

Install sendmail on Ubuntu:

apt-get install sendmail
apt-get install bsd-mailx

How to extract file attachment from email file linux or .eml format:
Install uudeview:

#Debian or Ubuntu
sudo apt-get install uudeview
yum install uudeview

Run uudeview:

cd /home/oman0/mail/.hproxy@digi77_com/new  # change this to your mail box folder it can be /new or /cur
uudeview -c -i *  
# c for clear email when done -i for skip encoding confirmation 
uudeview -c -i mail-file-name





Usefull scripts to tune Mysql let it run at least for 48 hours before you run those scripts:
# Note binary log will slow down the performance of you Database make sure its always OFF!

# First is ssh script:

# Second is Perl script:
mv index.html 
# or 

To prune Mysql bin logs (This statement has no effect if the server was not started with the –log-bin option to enable binary logging. ):

PURGE BINARY LOGS TO 'mysql-bin.000054';

Examples on how to change Mysql variables values without shutting down this will be valid for one session only for permanent changes edit /etc/my.cnf:

select @@sql_log_bin;
set @@sql_log_bin=0;
select @@max_heap_table_size;
set @@max_heap_table_size=2147483648;
select @@tmp_table_size;
set @@tmp_table_size=2147483648;
set storage_engine=INNODB;
set global max_connections := 800;
set global max_allowed_packet=1073741824;
select @@key_buffer_size;
set global key_buffer_size=67108864;
select @@join_buffer_size;
set @@join_buffer_size=262144;
select @@query_cache_size;  
set global query_cache_size=0;
select @@query_cache_limit;
set global query_cache_limit=1048576;

Check if a column in MySQL table has duplicate values:

SELECT my_column, COUNT(*) as count
FROM my_table
GROUP BY my_column

How to select records from two tables wcf1_user_option_value and wcf1_user where wcf1_user.wbbPosts < 10 and birth date on wcf1_user_option_value not equal to 0000-00-00:

FROM wcf1_user_option_value
JOIN wcf1_user ON wcf1_user_option_value.userid = wcf1_user.userid
WHERE wcf1_user.wbbPosts < '10' and wcf1_user_option_value.userOption2 !='0000-00-00'

How to update a table based on information on another table giving that you have primary and foreign key on those tables:

UPDATE wcf1_user_option_value AS U1,  wcf1_user AS U2 
SET U1.userOption2 = '0000-00-00'
WHERE U1.userid =U2.userid  and U2.wbbPosts=127148

How to replace data in rows with a given word:

UPDATE wcf1_user SET `signature`=REPLACE(`signature`,'[size]','[/size]');

To increase the primary key id by given number:

update Table_name set id = id +844798 order by id desc;

To reset the primary key id to start from 1 and forward:

ALTER TABLE Table_name DROP id;

To change the next increment number for primary key id:

Alter table Table_name AUTO_INCREMENT=1087063;

Convert Your Database from Swidish_latin_ci to utf8 (utf8_general_ci) or (utf8_unicode_ci):

# Export DB as Latin
mysqldump --opt -u DB_USER --password=DB_Password --default-character-set=latin1 --skip-extended-insert DB_NAME -r Exported_DB_NAME.sql

# Check file encoding type it may be Asci or Latin 
file -ib Exported_DB_NAME.sql

# Now replace all words of latin1 to utf8
sed -e's/latin1/utf8/g' Exported_DB_NAME.sql > Exported_DB_NAME_sed.sql

# Get tools for conversion 
yum install dejavu-sans-mono-fonts
yum install recode

# Prepare your OS for UTF8 you may need to do this every time before you run the converting tool
export LANG=en_US.utf8

# This tools won't work with Arabic 
iconv -f ISO-8859-1 -t UTF-8 DB_NAME.sql  > UTF8_DB.sql

# So we use this tool instead to convert the Latin encoded DB to UTF8 
recode ms-arab Exported_DB_NAME_sed.sql  

# Import you UTF8 DB
mysql -u DB_USER --password=DB_Password --default-character-set=utf8 DB_NAME < Exported_DB_NAME_sed.sql 

Export specific table:

mysqldump -u DB_USER --password=DB_Password --default-character-set=utf8 --skip-extended-insert DB_NAME Table_Name > Exported_DB_Table_NAME.sql

Export specific table row by row:

mysqldump --opt -u DB_USER --password=DB_Password --default-character-set=utf8 --skip-extended-insert DB_NAME Table_Name > Exported_DB_Table_NAME.sql

Restore specific table:

mysql -u DB_USER --password=DB_Password --default-character-set=utf8 DB_NAME < Exported_DB_Table_NAME.sql

Export and Compress the DB:

mysqldump -u DB_USER --password=DB_Password --default-character-set=utf8 --skip-extended-insert DB_NAME | gzip -9 > Exported_DB_NAME.gz

Export 100 rows only of the DB Table:

mysqldump -u DB_USER --opt --where="1 limit 100" --password=DB_Password --default-character-set=utf8 --skip-extended-insert DB_NAME Table_Name > Exported_DB_Table_NAME.sql

Restore a single table from a full mysql mysqldump file:

sed -n -e '/CREATE TABLE.*`mytable`/,/CREATE TABLE/p' mysql.dump > mytable.dump

To change MySQL data directory:

# Stop mysql
/etc/init.d/mysql stop

# Copy mysql folder
cp -R -p /var/lib/mysql /home

# Create temp folder and change owner
mkdir /home/temp
chown mysql.mysql /home/temp

# Edit mysql config file
nano /etc/my.cnf


# Start mysql
/etc/init.d/mysql restart

# If everything  is ok we delete the original data directory
rm -fr /var/lib/mysql

To repair innodb tables on startup:

innodb_force_recovery = 1

If mysql refuses to start:

ps aux | grep mysql
sudo kill -9 2804 3009 # based on top cpmmand results
# Then start my sql in safe mode:
sudo -u mysql mysqld_safe --log-error=/tmp/mysql.log
# Watch logs for error
tail -f /tmp/mysql.log

To restore mysql files specially ibd format for Worpress make sure you do the following:

/etc/init.d/mysql stop
chmod 660 filename
chown mysql.mysql filename
/etc/init.d/mysql start

Stop mysql service:

/etc/init.d/mysql stop

Start mysql service:

/etc/init.d/mysql start

InnoDB maintains a cache memory, called the buffer pool. With the parameter innodb_buffer_pool_size you can define the size of this pool. The required size can be calculated with the following query:

SUBSTR(' KMG',IF(PowerOf1024<0,0,
IF(PowerOf1024>3,0,PowerOf1024))+1,1)) recommended_innodb_buffer_pool_size
FROM (SELECT SUM(data_length+index_length) KBS FROM information_schema.tables
WHERE engine='InnoDB') A,
(SELECT 3 PowerOf1024) B;

PHP script that would convert DB + Tables + Columns into utf8_unicode_ci but it wont convert the data that is already stored it will work for future inserted data:

// Configuration Section
$server = 'localhost'; //probably localhost but change if required
$username = 'DB_USERNAME';
$password = 'DB_PASSWORD';
$database = 'DB_NAME';
$new_charset = 'utf8'; // change to the required character set - you're probably changing to utf8 ?
$new_collation = 'utf8_unicode_ci'; // change to the required collation - you're probably changing to utf8_general_ci ?

// Connect to database
$db = mysql_connect($server, $username, $password); if(!$db) die("Cannot connect to database server -".mysql_error());
$select_db = mysql_select_db($database); if (!$select_db) die("could not select $database: ".mysql_error());

// change database collation
mysql_query("ALTER DATABASE $database DEFAULT CHARACTER SET utf8 COLLATE $new_collation");
print "<br/>Changed collation of DATABASE $database to $new_collation<br/>";

// Loop through all tables changing collation
$result=mysql_query('show tables');
while($tables = mysql_fetch_array($result)) {
$table = $tables[0];
mysql_query("ALTER TABLE $table DEFAULT CHARACTER SET $new_charset COLLATE $new_collation");
print "<br/>Changed collation of $table to $new_collation and charset of $new_charset<br/>";

// loop through each column changing collation
$columns = mysql_query("SHOW FULL COLUMNS FROM $table where collation is not null");
while($cols = mysql_fetch_array($columns)) {
$column = $cols[0];
$type = $cols[1];
mysql_query("ALTER TABLE $table MODIFY $column $type CHARACTER SET $new_charset COLLATE $new_collation");
print "<br/>Changed collation of $table and $column to  $new_collation and charset of $new_charset<br/>";

print "<br/>Changed collation of $table to $new_collation<br/>";
print '<br/>The collation of your database $database has been successfully changed!<br/>'; 

# Put it on a file and run it like this on SSH
php latinToutf.php

Shell script to backup Mysql database one by one each on separate file:

# Prepare mysql and rest
echo "Backing mysql folder at: /home/mysql " $fulldate

# MySQL User
# MySQL Password
PASSWORD='Your DB Password goes here'
start=$(date +%s.%N)
bakdate="`date +%y%m%d`"

echo "Starting MySQL Backup";
echo `date`;
databases=`mysql --user=$USER --password=$PASSWORD -e "SHOW DATABASES;" | tr -d "| " | grep -v Database`
for db in $databases; do
    if [[ "$db" != "information_schema" ]] && [[ "$db" != _* ]] ; then
        echo "Dumping database: $db"
        mysqldump --force --opt --user=$USER --password=$PASSWORD --databases $db > $OUTPUT/$domanvalue-$bakdate-$db.sql
	    7za a -tzip -pYour7zippasswordgoeshere -mem=AES256 $domanvalue-$bakdate-$ $domanvalue-$bakdate-$db.sql
		rm -f $OUTPUT/$domanvalue-$bakdate-$db.sql
echo "Finished MySQL Backup";


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Crypto currency , security , coding addicted I am not an expert or a professional I just love & enjoy what I am addicted on🤠

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