A command line interface or CLI is a user interface to the operating system where the user reacts to a visual prompt. You have to type a command on a particular line and the system responses back. You then need to enter one more command and the process continues. Users, in the modern scenario, prefer using a graphical interface or GUI offered by most of the operating systems like Windows, Mac OS, etc. On the other hand UNIX offers both the command line and graphical interface. If you are a user of Linux or OSX, you must have come across the command line which is a command to enable a feature or fix a problem. Is It Really Necessary? It is really easy to ignore the use of command line as GUI is sufficient for most of the users, but if you are on the pro level, you really cannot ignore it. While doing a web development, you can understand that command line is a very powerful tool. The command line helps you to do certain things automatically which otherwise you would be doing the same thing over and again. It really doesn’t take much time to learn the command line. Spending few hours can acquaint you with all the commands of command line. Once you start you will understand that there are many such tools which work only in command line and those tools are really worth. A holder of Red Hat Certification knows the real value of Command line. Top Three Online Resources to Learn Command Line You can learn these command line tools by enrolling any Linux courses and can also learn it online. Few such online courses are: Learn the Command Line, a course offered by Codecademy which is all interactive. Learning the Command line from the Command line Crash Course A comprehensive guide for using Linux by Linux Tutorials. Do not ignore the use of command line rather, learn it to use it. Save