All DNS records have a TTL (time to live) property that specifies the maximum amount of time the record may be cached. In Linux you can make the DNS TTL lookup using the dig command. You can both check the current domain remaining TTL as well as find out what TTL value is set on […]
Normally, log rotation in Linux is handled by daily cron job. The default configuration file is /etc/logrotate.conf and service or server specific configurations are stored in /etc/logrotate.d directory. Sometimes it needs to force rotation of some files manually. Below you will find how to debug and force logrotate manually.
By default, the docker ps command shows only running Docker containers. With the specific options it is possible to list all Docker containers or filter output by the stopped containers only. Below you will find how to list all Docker containers and how to list just running or just stopped Docker containers.
To delete a particular Docker image firstly you have to find out the IMAGE ID by listing the all local Docker images. When the image for deletion is identified it can be removed with the docker rmi command. From the command-line it is also possible to remove unused Docker images (not used by any containers) […]
To delete a particular Docker container firstly you have to find out the CONTAINER ID or NAME by listing the all Docker containers. When the container for deletion is identified it can be removed with the docker rm command. From the command-line it is also possible to remove stopped (unused) Docker containers only or, if […]
What is Vagrant? Vagrant is a simple and easy to use tool that makes it really easy to manage virtual machines from the command-line interface. Vagrant out of the box supports VirtualBox, Hyper-V, Docker and has the ability to manage other types of machines, like VMWare or Amazon EC2, by using other providers. In this […]
Sooner or later, every person who works with Ubuntu wonders – what version of Ubuntu do i have? It is especially important to know the version of Ubuntu that you are running if you want to install some software and need to choose which version of Ubuntu the installer should be downloaded for. From this […]
Many companies on the Internet allow to access their services from certain countries only. If you need to access a website that is blocked from your country – you can use a Tor Browser. By default, the Tor Browser picks random exit nodes from any country, but it can be configured to use the exit […]
For ones, who want to build and run Docker containers on Ubuntu-16.04 – first of all it is required to install Docker itself. To install the latest version of Docker and to be able to upgrade it easily in future – it is recommended to install Docker from the official repository. In this guide i […]
By default, yum installs the latest version of a package among the all versions available in enabled repositories. Often it is required to install not the latest one, but some specific version or downgrade the already installed package to an older version. In this note i show how to make yum list all available versions […]