Linux

usermod

August 5, 2024January 30, 2018 by Yujin Boby

On CentOS, the wheel group allows users in this group to run commands as user root with sudo. To add a user…

Install Node.js on CentOS Server

October 15, 2020January 30, 2018 by Yujin Boby

You can find latest version of Node.js at https://nodejs.org/en/ To install Node.js on CentOS 7/8 Add node.js repository NodeJS 12.x curl -sL…

lftp

July 17, 2019January 29, 2018 by Yujin Boby

Download files Download all files from FTP server using lftp Download all files from SFTP server using lftp Upload files Upload all…

load

March 23, 2026January 27, 2018 by Yujin Boby

Load Testing Here are some commands used to investigate server load/performance issue. uptime free -m top atop htop Checking logs dmesg |…

SSH

February 21, 2026January 27, 2018 by Yujin Boby

SSH Connection Errors SSH ProxyJump (Jump Host/bastion host) SSH Errors SSH Protect SSH Configuration Options Only allow a specific user to login.…

Force SSH client to use Password Authentication

January 27, 2018 by Yujin Boby

Some times you may need to test if password authentication works for SSH and you have SSH key authentication already set. You…

Generate CSR using OpenSSL

July 29, 2024January 25, 2018 by Yujin Boby

Info needed for Certificate Signing Request (CSR) generation Generate CSR Here is oneliner For normal SSL, enter the domain without www. For…

discourse

November 23, 2020January 25, 2018 by Yujin Boby

Discourse store data in folder /var/discourse/shared/standalone root@forum:/var/discourse/shared/standalone# ll total 48 drwxr-xr-x 12 root root 4096 Jan 24 05:04 ./ drwxr-xr-x 4 root…

Convert PPK file to PEM

February 23, 2022January 24, 2018 by Yujin Boby

To convert putty PPK format file to Linux OpenSSL format, run puttygen SSH_KEY.ppk -O private-openssh -o SSH_KEY.pem To install puttygen, On CentOS…

memcached

January 18, 2026January 23, 2018 by Yujin Boby

limit_maxbytes – maximum memory allowed. To change this, edit /etc/memcached.conf, change -n option. bytes – currently used memory. evictions – number of…

MySQL Backup using mysqldump

August 10, 2023January 23, 2018 by Yujin Boby

Create file mkdir /usr/serverok/ vi /usr/serverok/mysqldump-backup.sh Add #!/bin/bash # Author: Yujin Boby # Email: admin@serverok.in # Web: https://serverok.in/mysqldump-backup DB_BACKUP=”/home/serverok-mysql-backup/`date +%Y-%m-%d`” mkdir -p…

speedtest

March 29, 2019January 22, 2018 by Yujin Boby

https://gtmetrix.com https://tools.pingdom.com https://developers.google.com/speed/pagespeed/insights/ Test network performance with iperf Install SpeedTest cli on Ubuntu