Shane Rutter Blog

Category: Knowledge Base

  • NCDU – Find what’s using all your disk space on linux based system

    NCDU – Find what’s using all your disk space on linux based system

    NCDU is a text-based user interface, it allows you to visually see how and where disk space is being used via an easy-to-use interface. Simple run the command in the current directory to see a directory tree of folders & files and their space usage.

    I use this tool mainly for analysing why a server is running out of disk space, determine the reason why and if it’s simply expanded the disk space or is there unused files / massive logs which can be purged.

    Install

    Run the required command for your linux OS version.

    sudo apt install ncdu

    sudo yum install ndcu

    How to use

    Simple navigate to a directory you want to check and run the command:

    ncdu

    If you want to scan the whole system go to the root directory:

    cd /
    ncdu

    You can also specify a directory if you don’t want to change directory:

    ncdu /home

    Windows Server / PC

    For windows-based machines I use a bit of software called TreeSize, it does the same thing as NCDU, allowing you to see how your disk space is being used on a windows based OS.

    TreeSize on windows PC showing disk space usage
    TreeSize on windows PC showing disk space usage

     

    This is provided as it and may require changes to work for your needs.

     

  • Linux: Killall command

    It is your responsibility to ensure safe usage of these commands, improper usage could cause damage to services and file systems. We will not be held responsible.

    There is a number way of killing processes on a Linux based OS, killall is one of these methods. It’s always good to be ready to kill an unwanted process or a rogue process which is eating resources.

    Usage

    Kill all instances of the “httpd” process

    Kill all proccesses running under the user “postfix”

    Kill a specific process but its full path

    Command not found?

    It does not always come pre-installed, it’s simple to install.

    Ubuntu / Debian

    RHEL – Red hat / Fedora / CentOS

    This package also contains the following useful programs:

    • fuser – identifies what processes are using files.
    • killall – kills a process by its name, similar to a pkill Unices.
    • pstree – Shows currently running processes in a tree format.
    • peekfd – Peek at file descriptors of running processes.
  • What is a server

    What is a server

    A server is a computer designed for a specific task such as running a website, a server tends to be powered up more often compared to a regular computer with most servers running 24/7. Servers are a major part of our everyday live, the internet is a collection of hundreds of thousands of servers all working together performing various tasks. (more…)

  • What is SSH (secure shell)?

    What is SSH (secure shell)?

    SSH short for secure shell is a network protocol allowing communications between two computers, it is natively found on Linux based operating systems and used to remotely control computers and server via a command line interface. SSH was created to replace older insecure software such as telnet, telnet lacked encryption allowing anyone to intercept the data transfer. For example it was possible someone could steal the username and password used which would give them remote access to the system. (more…)

  • Why a VPS (virtual private server)?

    Why a VPS (virtual private server)?

    VPS are a cheap and efficient way of owning a server without having to maintain the physical hardware, infrastructure and costs involved when renting server space. You can purchase a new VPS from most providers and within 15 minutes you can be installing your software and services. A VPS is just like owning a physical server you can install and do what you want with it. (more…)

  • What is a VM (virtual machine) or VPS (virtual private server)

    What is a VM (virtual machine) or VPS (virtual private server)

    I’m going to talk about virtual machines (VM) before I go onto virtual private servers (vps), to understand what a vps is you need to understand what a vm is as they are very similar (practically the same thing). A VM is a virtualized (virtual) operating system running inside a master operating system, for example we have a physical computer running windows XP this is known as the master, we install virtualization software which allows us to create virtual computers inside the master, multiple virtual machines can be installed on a single master. (more…)