For the system administrator, checking that disks are working properly is a big concern. In many cases, you will have to list all the disks available on your computer, with their sizes, in order to make sure that they don’t run out of space. If they were to run out of space, you could essentially have your server down, preventing all your users from accessing it. In this tutorial, we are going to see how you can easily list disks available on your Linux machine. Prerequisites For some of the commands used in this tutorial, you will need administrator rights in order to have the full output of ..read more

As a network engineer, you probably spend a lot of time thinking and planning your network infrastructure. You plan how computers will be linked, physically using specific cables but also logically using routing tables. When your network plan is built, you will have to implement every single link that you theorized on paper. In some cases, if you are using Linux computers, you may have to add some routes in order to link it to other networks in your company. Adding routes on Linux is extremely simple and costless : you can use the Network Manager daemon (if you are running a recent distributio ..read more

When working on software projects, it is quite common for developers to add new files to their repositories. In some cases, you may want to change some of your existing files. In other cases, you may want to add untracked files to your repository. In both cases, you will need to use the same Git command : Git Add. In this tutorial, you will learn how you can easily add all your files to your Git repository. Determine your Git version Depending on the current Git version that you installed on your computer, the “git add” command can differ. To determine your current Git version, use “git” follo ..read more

In one of our previous articles, we learnt how you can encrypt your entire root filesystem on Linux easily. However, in some cases, you may want to encrypt one simple partition that may store some of your important files. As you already know, encrypting your disks is crucial. If your laptop were to be stolen, you would probably lose all your personal information. However, there are some ways for you to cope with this problem : by encrypting your disk partitions. In this tutorial, you will learn about all the steps necessary to encrypt an entire disk partition, secure it with a passphrase or wi ..read more

DNS, short for the Domain Name System protocol, is used on Linux systems in order to retrieve IP addresses associated with names. For example, when you are performing a ping request, it is quite likely that you are using the DNS protocol to retrieve the server IP. In most cases, the DNS requests that you perform are stored in a local cache on your operating system. However, in some cases, you may want to flush the DNS cache of your server. It might be because you changed the IP of a server on your network and you want to changes to be reflected immediately. In this tutorial, you are going to l ..read more

If you are working in a medium to big-sized company, it is quite likely that you are working with many other system administrators. As you are performing your sysadmin tasks, some users may try to connect to your server in order to perform their daily tasks. However, in some cases, you may find that something has changed on your server. As a consequence, you are wondering who performed the change. Luckily for you, there are many ways to find who last logged in on your server. In this tutorial, you will learn about the different useful commands that you can use in order to check the last logins ..read more

As a system administrator, you probably already know how important it is to encrypt your disks. If your laptop were to be stolen, even a novice hacker would be able to extract the information contained on the disks. All it takes is a simple USB stick with a LiveCD on it and everything would be stolen. Luckily for you, there are ways for you to prevent this from happening : by encrypting data stored on your disks. In this tutorial, we are going to see the steps needed in order to perform a full system encryption. You may find other tutorials online focused on encrypting just a file or home part ..read more

When using Git, it is quite common for developers to add new files to their repositories during development. Most of the time, files are associated with commits. Developers often start by adding files to their staging area just before committing them to the Git repository. However, in some cases, you may want to undo a “git add” operation that you just performed. Maybe you added too many files to your staging area or you may feel that a file needs more work because committing it to the repository. In this tutorial, you will learn how you can simply undo a Git add operation that you just did. U ..read more

If you are a conscientious system administrator, you have probably already wondered how you can make your files secure. Nowadays, as system attacks get more and more frequent, it isn’t probably a bad idea to think about encrypting your files. On Linux, there are multiple of encrypting files, directories or filesystems : namely using the LUKS disk encryption specification or simple tools such as GnuPG. In this tutorial, you will learn how you can easily encrypt files and directories on Linux using the GnuPG tool as well as the zip utility. Encrypt Files using passphase protection One of the eas ..read more

As a system administrator, you are probably dealing with a lot of services every day. On Linux, services are used for many different purposes. They may be used in order to start a SSH server on your machine or they can perform some operations on a specific hour or day. Whether you are using a Debian based distribution or a RedHat one, querying services is very similar. However, given the distribution you are using, and more specifically the initialization system (init or systemd), you may have to use different commands. In this tutorial, you will learn how you can, given your system manager, l ..read more