UNIX

In the world of Linux commands, killall serves as a powerful tool for sending signals to multiple running processes simultaneously. While the traditional kill command targets a specific process ID, killall broadens its scope by enabling users to terminate multiple processes at once. Syntax The basic syntax of the killall command is as follows: killall <name> Here, <name> refers to the name of a program or process. For instance, if you have multiple instances of the top program running and want to terminate all of them, you can simply execute killall top....

The rmdir command is used to delete folders in a Linux environment. Similar to how you can create a folder using the mkdir command, you can remove a folder using rmdir. Let’s take a closer look at how this command works. To delete a single folder, you can use the following command: mkdir fruits rmdir fruits This will create a folder called “fruits” and then remove it. If you have multiple folders that you want to delete, you can do so in one go....

Emacs is a highly versatile and powerful editor that has been the go-to choice for many UNIX users throughout history. The classic argument between vi and emacs enthusiasts has sparked countless debates and unproductive discussions among developers worldwide. To get started with Emacs, simply open a new session by invoking the command emacs. If you’re using Linux, this shouldn’t be a problem. However, if you’re on macOS, you’ll need to take an extra step....

The echo command is a versatile tool that is used to print the argument passed to it. In this guide, we will explore the various ways you can use the echo command in a Linux environment. To begin, let’s look at a simple example: echo "hello" When this command is executed, it will print hello to the terminal. Appending the output to a file is also possible with the echo command:...

The env command is a versatile tool used in Linux, macOS, WSL, and UNIX environments to run commands while manipulating and interacting with environment variables. Passing Environment Variables One of the main use cases for the env command is to pass environment variables to a command, without permanently setting them in the current shell. For example, if you want to run a Node.js app and set the USER variable to it, you can use the env command as follows:...

The printenv command is a useful tool for printing the values of environment variables in a Linux, macOS, or UNIX environment. In this guide, we will explore how to use this command effectively. Understanding Environment Variables Environment variables play a crucial role in setting system configurations and customizing shell behaviors. They can be set by the system itself or by your own shell scripts and configuration files. Printing All Environment Variables To print all the environment variables to the terminal, simply execute the printenv command....

In this blog post, we will explore the tail command, a highly useful tool in the UNIX command line. This command is available on most Unix-like systems, including macOS and Linux. According to the tail command’s man page, it allows us to display the last part of a file. Here is an example screenshot of the man page for reference. One common usage of the tail command is to display a specific number of lines from the end of a file using the -n option....

In the world of Linux, the sort command is a powerful tool that allows you to sort records or lines of text. Whether you have a text file with a jumbled list of names, or you want to sort the output of another command, sort has got you covered. Let’s start with a simple example. Suppose you have a text file that contains the names of dogs: Spot Rusty Fido Max To sort these names in alphabetical order, you can use the sort command:...

A concise guide to understanding and utilizing the UNIX filesystem commands in an efficient manner. Introduction This guide provides a comprehensive overview of the UNIX filesystem commands, with a focus on macOS and GNU/Linux systems. Both of these systems are classified as UNIX, and they share many similarities in terms of their filesystem utilities. Although Windows has a different filesystem structure, users can still access and use similar utilities by installing the Windows Subsystem for Linux on Windows 10....

In the Linux, macOS, and UNIX operating systems, every file has three permissions: read, write, and execute. These permissions are represented by a string of characters when using the ls -al command. Understanding and changing file permissions is important for managing access to files and directories. Let’s dissect the permission string: drwxr-xr-x. The first character represents the type of file: - indicates a normal file d indicates a directory l indicates a link The next three sets of characters represent the permissions for the owner, group, and everyone else, respectively....