If for some reason you do not want to update your server kernel but want to update other packages running on CentOS, here is how you can do.
Update can be done using yum command and to exclude kernel from update we need to add exclude command.
Login to your server as root via SSH and run following command:
yum -y --exclude=kernel\* update
OR
yum -y -x 'kernel*' update
Above command will update all packages but will leave kernel update on a CentOS server.
If you want to copy a file / folder from one server to another, you can use wget or scp command. In this tutorial I will show how to use scp command to copy files / folder from one server to another.
Server One IP is: 1.1.1.1
Server Two IP is: 2.2.2.2
Suppose you want to copy a file from server one to server two.
Location of file on server one is: /home/filename.txt
Login to server two via SSH and run following command
scp root@1.1.1.1:/home/filename.txt /home/
This will copy filename.txt file from server one to server two and save in /home directory.
Suppose you want to copy a complete folder from server one to server two.
Let’s say you want to copy /backup folder from server one to server two.
Login to server two via SSH and run following command
scp -r root@1.1.1.1:/backup /foldername
This will copy /backup directory from server one to server two and save in /foldername directory.
PuTTY is a free and open-source SSH / telnet client for Windows and Unix platforms.
A newbie can find it difficult how to use copy / paste in putty.
Using left click of your mouse select the text you want to copy.
That’s it. The selected text will be copied to your clipboard.
Simply right click and it will paste the copied text.
If you use ping command in SSH, it will continue pinging and extending output lines without any stoppage. Something like below screenshot.
Here is how you can exit from ping command. Simply press below key on your keyboard.
The default SSH port on centOS 7 (32-bits / 64-bits) server is 22. But for security reasons, it is recommended to change the default SSH port number. Here is how you can change your centOS 7 server / VPS SSH port number.
Login to your server as root via SSH.
Backup the configuration file before editing it.
cp /etc/ssh/sshd_config /etc/ssh/sshd_config.backup
Open following file in any text editor like nano.
nano /etc/ssh/sshd_config
Find following code in /etc/ssh/sshd_config file.
#Port 22
Change this line to new port number and remove #
Like if we want to make 2121 as new ssh port number.
Port 2121
Save the change using: Ctrl + O
Exit nano editor using: Ctrl + X
Allow the new port in firewall. If you use any third party firewall like csf firewall, add the new port in allowed port list.
If you are using default OS firewall, use following command to allow new port.
Below command will allow port 2121.
firewall-cmd --add-port 2121/tcp --permanent firewall-cmd --add-port 2121/tcp
Restart SSH using below command.
service sshd restart
Don’t close your current SSH session. Instead start a new SSH session in a new widows with new SSH port number.
If you are able to login using new SSH port number, you have successfully changed your server SSH port number.
If you are unable to login using new SSH number, it means you have done something wrong. You should consider reverting all changes made in step 3.
We generally use wget command to download any particular file on a server. But what if I want to download a complete directory / folder.
Here is how you can download a full directory / folder using wget SSH command. Suppose, I want to download all files and folders under http://www.lophost.com/foldername
So, my SSH command will be:
wget -r http://www.lophost.com/foldername/
cPanel offers you to schedule backup and retain backup of server and accounts. But if you need to run backup manually, you can do it from SSH. Login to your server as root via SSH and run following command.
/usr/local/cpanel/bin/backup
If the backup is up-to-date, you can force to run backup using below command
/usr/local/cpanel/bin/backup --force
/scripts/cpbackup
If the backup is up-to-date and you wish to run backups anyway, use:
/usr/local/cpanel/scripts/cpbackup --force
Please follow below steps to change root password via SSH of a dedicated server / VPS.
Login as root to your server via SSH.
Run below command
passwd
Enter your new password and press enter.
Re-enter your new password to confirm the password.
If completed successfully, the shell will show you a successful message showing
passwd: all authentication tokens updated successfully.
Done!!!
To create a file via SSH use touch command.
Like I want to create a file lophost.text in /home, I will use below command
touch /home/lophost.txt
This will be a blank file, which we can edit later.
Use command mkdir to create a new folder / directory. Like I want to create a folder lophost in /home
mkdir /home/lophost
CD command is used for navigation to different directories on a Linux machine. Below I have explained some basic things about CD command.
If you want to know your current directory, run below command:
pwd
when you login as root your default directory is
/root
Support you want to move to /home directory, use below command
cd /home
To move to one level up directory use:
cd ..
cd /
cd ~
This will take the use to his home directory. Like for user root home directory is /root
