Network Diagram

The typical network diagram. The internet terminated at the modem and the modem is connected to the server/network switch through Ethernet cable. Configure the modem as Bridge mode and dial the same from the server to get the WAN IP.

• Check Disk IOPS using dd command in Linux

[root@testsvr01~]# dd if=/dev/zero of=/tmp/temp.img bs=2G count=1 oflag=dsync status=progress
2147479552 bytes (2.1 GB) copied, 3.478083 s, 617 MB/s
0+1 records in
0+1 records out
2147479552 bytes (2.1 GB) copied, 3.4785 s, 617 MB/s
[root@testsvr01~]#

• Create Sudo / Root Privilege  User

[root@testsvr01 ~]# useradd sysadmin -G wheel

• Add Sudo Permission in the existing  User

[root@testsvr01 ~]# usermod -aG wheel sysadmin

• Find and Replace a word in a File 

[root@testserver01 opt ]#   sed -i 's/find_pattern/replace_pattern/g'  /opt/filename

• Find and Replace a word in all Files in a folder

[root@testserver01 opt ]# sed -i 's/find_pattern/replace_pattern/g'   /opt/*.filetype

• Create RSA Key pair for accessing SSH Service

[root@testserver01 ~]# ssh-keygen
Generating public/private rsa key pair.
Enter file in which to save the key (/root/.ssh/id_rsa):
Created directory '/root/.ssh'.
Enter passphrase (empty for no passphrase):
Enter same passphrase again:
Your identification has been saved in /root/.ssh/id_rsa.
Your public key has been saved in /root/.ssh/id_rsa.pub.
The key fingerprint is:

Rsync Copy Files & Folder through SSH

• Install Rsync in Both Server

[root@testsvr01 ~]# yum install -y rsync

[root@testsvr02 ~]# yum install -y rsync

• Run below command for Sync files and Folder

[root@testsvr01 ~]# rsync -v -r -e ssh --progress /opt/soruce_dir/* root@testsvr02:/opt/dest_dir/

Mount Window's Share in Linux

Eg : Windows Share URL: \\192.168.10.1\share

[root@testsvr01 ~]# mount -t cifs "//192.168.10.1/share" -o username=windows_user,password=SecurePass "/opt/mount_location/"

C:\Users\User> netsh wlan show profiles

Profiles on interface Wi-Fi:

Group policy profiles (read only)
---------------------------------
    <None>

User profiles
-------------
     All User Profile     : BSNL_FTTH
     All User Profile     : CISCO
     All User Profile     : Belkin

C:\Users\User>netsh wlan show profile name=BSNL_FTTH key=clear

Profile BSNL_FTTH on interface Wi-Fi:
=======================================================================

Node 14 installation
----------------------------------
[root@appsvr01]# curl -sL https://rpm.nodesource.com/setup_14.x | sudo bash -
[root@appsvr01]# yum install -y nodejs
[root@appsvr01]# node --version

----------------------------------

[root@appsvr01]# node --version
v14.21.1

[root@dbserver1 ~]# su postgres

bash-4.4$ psql -A -t -c "select version()"

PostgreSQL 12.12 on x86_64-pc-linux-gnu, compiled by gcc (GCC) 8.5.0 20210514 (Red Hat 8.5.0-10), 64-bit