When working with various Linux commands, you may be wondering what version of the command you are using. Of course, the version relates to the binary executable file itself, and traditionally is maintained by the system package manager, which is responsible for checking on updated versions and installing them at the user’s discretion. Commands in Linux typically undergo slow, subtle changes. Some commands have not changed much at all since the 70s, when they were introduced on Unix. Others have new versions developed regularly, and you need to check your version to know which features it has. In this tutorial, you will learn how to check the version of a command on a Linux system.
PDF documents are commonly used to hold lengthy amounts of text, especially for formal matters like contracts or terms and conditions. These PDF documents can prove unwieldy in certain scenarios, since a PDF reader application is required to open them, and a PDF editor must be used for changing the contents.
Linux commonly uses base64 to encode and decode data. This method of encoding provides a reliable way for data to be transmitted and stored. The encoding process will convert binary data to ASCII characters, making it usable by a variety of services (such as OpenSSL) that require readable ASCII character transmission as opposed to binary. Afterwards, the data can be decoded back to binary data. In this tutorial, you will see how to use the
base64 command to decode and encode data on a Linux system.
The cp command is used to copy files and directories on a Linux system. If a user tries to copy a file over to a location that already contains the same file name, the default behavior of
cp is to overwrite the destination file with the source file. However, on some Linux systems, this behavior can be configured differently, and the user might see a prompt to confirm overwriting in their terminal. When copying many files, this prompt can get repetitive and annoying to deal with. In this tutorial, you will learn how to say YES to ALL with the
cp command when trying to copy files via the Linux command line.
When you need to quickly or forcibly close a running process on a Linux system, many users will try to determine the process ID and then kill a process by its ID. While this works fine, it is sometimes easier or more convenient to kill a process by name. This way, we get to skip the step of looking up the process ID, and let our terminal do the work for us.
Everything that is currently running on your Linux system is a process. Some processes are meant to run in the background (application updates, for example), so you may not be readily aware of their existence. And other processes (a web browser, for example) are very apparent, and get started or stopped by the user on a constant basis. All of these processes are assigned an ID number, called PID or “Process ID”, and can be referenced in various situations, including killing a running process via the process ID.
Environment variables contain data about the current system configuration. These variables are mostly referenced by scripts and system programs that need some information on the current configuration in order to adapt to various scenarios. For example, a script might check an environment variable to see what language is set on the computer, and then output prompts in the target language. One of the most commonly accessed environment variables is the PATH environment variable.
Most of us longtime Linux users have the
ifconfig command seared into our brain, after years of repetitive use. It comes as a shock to some when they type the command and are met with an error message (ifconfig command not found). Indeed, the command has become deprecated, but it’s still possible to install ifconfig command.
When working with text on the command line, it is sometimes useful to join multiple lines together. Rather than going through text files and manually shifting lines around to be on the same line, our Linux system provides us with multiple tools to simplify this task for us. Log files are a good example of text that is usually split up onto multiple lines, and sometimes it is easier to visualize the data when some lines are joined together. In this tutorial, we will show you several ways to join lines of a file together on a Linux system.
The shell on a Linux system is the layer that interprets the commands being executed by the user, and translates them into a language that the operating system can understand. The Bash shell is the default one in Linux, and typically what all users become familiar with first. But there are a lot of other shells that can be used, too; like sh, zsh, ksh, csh, and tcsh, to name a few.
Have you ever been in the middle of using your command line terminal, and suddenly needed to open the file explorer? In some cases, it can be easier or more convenient to visualize the contents of a directory from a graphical file explorer, rather than using the ls command or others to sift through the files. Fortunately, Linux gives us an easy way to open a file explorer and have it navigate directly to the directory we are currently viewing in the terminal.
The telnet utility, a once common protocol that graced the terminal of every system administrator and power user, was a precursor for the SSH protocol. Since telnet sends all data, including usernames and passwords, over the network in clear text, it is not often used anymore. Despite the other protocols that have come to replace it, telnet remains an ideal utility to test the connection to a certain port of a device, and can be handy in other niche scenarios, or even send an email.