Installation of missing php-mbstring on RHEL 7 Linux

The php-mbstring is part of Redhat’s server optional packages. If you have a current subscirption all you need to do is to enable this repository using:

[root@rhel7 ~]# subscription-manager repos --enable=rhel-7-server-optional-rpms

and use yum to install php-mbstring. In case that you do not have a current Redhat subscription you can install php-mbstring directly from IUS project repository:

[root@rhel7 ~]# wget
[root@rhel7 ~]# wget
[root@rhel7 ~]# rpm -Uvh *release*.rpm

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Check status, enable and start the SSH Server on Fedora Linux

How to install, start and connect to SSH Server on Fedora Linux

The tutorial will explain the basics behind SSH server and SSH client connections on Fedora Linux Workstation. By default the SSH server on Fedora Workstation may be installed but not enabled. This will cause a following error message when connecting via SSH client:

ssh: connect to host fedora-workstation port 22: Connection refused

In this tutorial you will learn:

  • How to Install SSH server
  • How to enable SSH server
  • How to Start SSH server
  • How to Connect to SSH server

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Crontab entry format and syntax example

Linux Crontab Reference Guide


Every user, as well as administrator of the Linux system, very often need to execute some programs automatically on regular basis.

For example, an administrator may need to monitor a disk usage of a system. In this case, a cron scheduler is a very handy tool to achieve this goal.

Let’s say that the system administrator needs to execute /usr/local/sbin/ script every Sunday at 2:36AM. In this case the administrator would edit his crontab file as shown on the figure below:

$ sudo crontab -e 

The format of Crontab entry is simple as it is divided into 7 fields separated by spaces or tabs. The 6th field, in this case, the username, can be omitted as it is only used by the system-wide crontab scheduler.

The following figure illustrates a single Crontab entry to allow automatic script execution every Sunday at 2:36AM:

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Linux commands tutorial

Linux Commands

Are you a beginner GNU/Linux user and wish to look beyond the usual window dragging and mouse clicking? This guide is intended for the absolute beginner users wishing to learn the basics of GNU/Linux command line. This tutorial intends to walk through basic Linux commands related to navigation, file and directory administration, software installation and basic system troubleshooting.

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Debian package

Easy way to create a Debian package and local package repository

This article describes a simple way to create a home made debian package and include it into a local package repository. Although we could use an existing Debian/Ubuntu package, we will start from scratch by creating and packaging our own trivial application. Once our package is ready, we will include it into our local package repository. This article illustrates a very simplistic approach, however it may serve as a template in many different scenarios.

In this tutorial you will learn:

  • How to create a trivial debian package
  • How to create a local debian repository
  • How to add the repository to the list of software sources

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Linux FileSystem Hierarchy Standard

Linux Filesystem Navigation Basics

This article explains basic commands for navigation within Linux file system. The diagram below represents (part of) a Linux file system know as Filesystem Hierarchy Standard. A line from one node to a node on its right indicates containment. For example, the student directory is contained within the home directory.

In this tutorial you will learn:

  • How to use pwd command
  • How to use cd command
  • How to navigate to user home directory
  • Difference between relative vs absolute
  • What is a parent directory

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Logical Volume Manager - Tutorial Scenario

Linux Logical Volume Manager (LVM) tutorial

Logical Volume Manager (LVM) is used on Linux to manage hard drives and other storage devices. As the name implies, it can sort raw storage into logical volumes, making it easy to configure and use.

In this guide, you’ll learn how LVM works on Linux systems. There’s no better way to learn about LVM than simply running through an example, which is exactly what we’ll do in the steps below. LVM works the same on any Linux distribution, so you can use any of the commands below on your own system.

Follow along with us as we use LVM to create partitions, physical volumes, a virtual group, logical volumes, and filesystems on a hard disk. We’ll also show how to mount, extend, and remove our newly created logical volumes. By the end of this tutorial, you’ll have a full understanding of how to use LVM and apply your own configurations.

In this tutorial you will learn:

  • How to install LVM on major Linux distros
  • How to create partitions
  • How to create physical volumes
  • How to create a virtual group
  • How to create logical volumes
  • How to create a filesystem on logical volumes
  • How to edit fstab to automatically mount partitions
  • How to mount logical volumes
  • How to extend a logical volume
  • How to remove a logical volume
Logical Volume Manager - Tutorial Scenario

Logical Volume Manager – Tutorial Scenario

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