How to Fix “unable to locate package openjdk-8-jdk” in Ubuntu Server

Fixing "unable to locate package openjdk-8-jdk" in your Ubuntu Server

By default, Ubuntu Server does not come with OpenJDK installed. OpenJDK must be installed manually from the repository. However, sometimes even after running “sudo apt-get update”, the OpenJDK package is not found on the repository, even though it should be available for installation. The installation will fail with the following error: How to Fix “unable …

How to Fix SSH Error: No matching key exchange method found. Their offer: diffie-hellman-group1-sha1

Fixing error on SSH: No matching key exchange method found. Their offer: diffie-hellman-group1-sha1

OpenSSH is a widely used SSH (secure shell) server and client used in the Unix world, including in Linux, Mac OS X, and BSD operating systems. OpenSSH allows for secure logins to a remote system. While the current version of OpenSSH is 8.6, there are a lot of older clients and servers still running for …

Fixing “failed to start mongod.service: unit mongod.service not found” Error in MongoDB

How to fix error when starting MongoDB service

MongoDB is a popular database engine used in conjunction with various scripting languages, particularly Python and Rails. Its strongest point is JSON-like data storage, which allows for the natural processing of data stored in the database. The query used by MongoDB is also in the form of JSON, which allows users to construct complex queries …

Issue with Cronjob “(cron) info (no mta installed, discarding output)”

Error with cronjob "(cron) info (no mta installed, discarding output)"

A cronjob is a scheduled task in Unix and Unix-like operating system environments, including Linux, Mac OS X, and FreeBSD. The operating system can execute various scheduled tasks, from opening a file to shutting down a system completely. Cronjobs can also be configured to run programs that need root access. However, like all software, cronjobs …

How to Install build-essentials in CentOS or Ubuntu

Installing build-essential in Ubuntu or CentOS

Linux is an operating system suited for software development. In Linux, you can build and run various software written in different languages, such as C, C++, Python, and Java. However, in default, mainstream Linux distributions do not bundle development tools – they have to be installed separately through the package manager upon successful installation of …

How to Fix Ubuntu Permission Denied When Using sudo Command

Fixing permission denied in Ubuntu when using sudo

Sudo, or “superuser do” is a very powerful command in Linux. It essentially allows you to run the command as root, the highest level of user in the Linux hierarchy, and analogous to administrator user account in Windows. Root users can execute very sensitive commands, such as formatting a hard drive and installing new hardware …

Installing VMware Tools in CentOS 7, The Complete Guide

How to install VMware Tools in CentOS 7

Nowadays, the use of virtual machines is widespread as virtualization allows you to run more than one operating system on one computer at the same time. One of the most popular hypervisors to run virtual machine is VMware. With VMware Workstation, you can install various guest operating systems, such as Windows, Linux, and FreeBSD. To …

How is SSH Different from Telnet?

SSH vs Telnet

If you have used Linux or other Unix-based operating systems (like FreeBSD or Mac OS X), you might be familiar with SSH, Telnet, or both. They are used for accessing systems remotely through the command line interface (CLI). Although they are often used interchangeably, they have several feature differences, which makes them suitable for different …