free space after file removal in linux

kill -9 $(lsof | grep deleted | cut -d " " -f4)

Ip-Table block-range-of-ip-addresses

To block 116.10.191.* addresses:

$ sudo iptables -A INPUT -s 116.10.191.0/24 -j DROP

To block 116.10.*.* addresses:

$ sudo iptables -A INPUT -s 116.10.0.0/16 -j DROP

To block 116.*.*.* addresses:

$ sudo iptables -A INPUT -s 116.0.0.0/8 -j DROP

Saving and restoring rules

$sudo aptitude install iptables-persistent
After the installation the initial setup will ask to save the current rules for IPv4 and IPv6, just select Yes and press enter for both.
If you make further changes to your iptables rules, remember to save them again using the same command as above. The iptables-persistent looks for the files rules.v4 and rules.v6 under /etc/iptables.

Download complete website excepting some extensions

use linux command to download all website excepting .js, .css, .gif, .png, .mp3, .exe

wget –mirror –random-wait –remote-encoding=utf-8 –reject ‘*.js,*.css,*.gif,*.png,*.mp3,*.exe’ [http://www.website.com]

Split contents of a directory into multiple sub directories

Just run this and hit enter in tme command line

i=0; 
for f in *; 
do 
    d=dir_$(printf %03d $((i/100+1))); 
    mkdir -p $d; 
    mv "$f" $d; 
    let i++; 
done

ENABLE ROOT LOGIN OVER SSH

1. As root, edit the sshd_config file in /etc/ssh/sshd_config:

   nano /etc/ssh/sshd_config

2. Add a line in the Authentication section of the file that says PermitRootLogin yes. This line may already exist and be commented out with a “#”. In this case, remove the “#”.

   # Authentication:
   #LoginGraceTime 2m
   PermitRootLogin yes
   #StrictModes yes
   #MaxAuthTries 6
   #MaxSessions 10

3. Save the updated /etc/ssh/sshd_config file.
4. Restart the SSH server:

   service sshd restart

Reset a MySQL root password

Stop the MySQL service

(Ubuntu and Debian) Run the following command:

sudo /etc/init.d/mysql stop

(CentOS, Fedora, and Red Hat Enterprise Linux) Run the following command:

sudo /etc/init.d/mysqld stop

Start MySQL without a password

Run the following command. The ampersand (&) at the end of the command is required.

sudo mysqld_safe --skip-grant-tables &

Connect to MySQL

Run the following command:

mysql -uroot

Set a new MySQL root password

Run the following command:

use mysql;

update user set password=PASSWORD("mynewpassword") where User='root';

flush privileges;

quit

Stop and start the MySQL service

(Ubuntu and Debian) Run the following commands:

sudo /etc/init.d/mysql stop
sudo /etc/init.d/mysql start

(CentOS, Fedora, and Red Hat Enterprise Linux) Run the following commands:

sudo /etc/init.d/mysqld stop
sudo /etc/init.d/mysqld start

Rsync command

Copy a File from a Remote Server to a Local Server with SSH

rsync -avzhe ssh root@[server-ip]:/root/source/ /dest/

Copy a File from a Local Server to a Remote Server with SSH

rsync -avzhe ssh backup.tar root@[server-ip]:/backups/

 

allow root access in phpmyadmin

skip Configuring phpmyadmin in installation steps

login to mysql

mysql -u root -p mysql

write this mysql command

 update user set plugin='' where user='root'; 

flush privileges; 

exit 
systemctl restart apache2 

Extending a Linux File System IN amazon EC2

1- expand the volume from amazon  ec2 Volumes dashboard

2- Expand the modified partition using growpart

sudo growpart /dev/xvdf 1

A look at the lsblk output confirms that the partition /dev/xvdf1 now fills the available space on the volume /dev/xvdf

3-  sudo resize2fs /dev/xvdf1

 

 

Change all files permissions to 644 and folders permissions to 755

find * -type d -print0 | xargs -0 chmod 0755 # for directories
find . -type f -print0 | xargs -0 chmod 0644 # for files