今天，大多数商业上流行的计算机操作系统和软件程序使用图形用户界面（GUI;有时发音为“gooey”）。它是一种允许用户使用鼠标，手写笔甚至手指操纵屏幕上元素的界面。例如，这种界面允许文字处理或网页设计程序提供WYSIWYG（所见即所得）选项。在GUI系统变得流行之前，命令行界面（CLI）系统是常态。在这些系统上，用户必须使用编码文本行输入命令。这些命令的范围从访问文件或目录的简单指令到需要多行代码的更复杂的命令。正如您可能想象的那样，GUI系统使计算机比CLI系统更加用户友好。几乎任何人都可以使用具有精心设计的GUI的计算机，无论用户在技术上如何精通。考虑今天在商店和餐馆中使用的现金管理系统或计算机化的收银机。输入信息就像在触摸屏上按下数字或图像一样简单，以便下订单和计算付款，无论是现金，信用卡还是借记卡。这种输入信息的过程很简单，几乎任何人都可以接受培训，系统可以存储所有销售数据，以便以后以无数种方式进行分析。在GUI界面之前的这些日子里，这样的数据收集更加劳动密集。想象一下尝试使用CLI系统浏览网页。用户不必指向并点击链接到视觉上令人惊叹的网站，而是必须调用文本驱动的文件目录，并且可能必须记住长而复杂的URL才能手动输入。当CLI系统占据市场主导地位时，它肯定是可能的，并且进行了许多有价值的计算，但它可能是乏味的，并且通常仅限于与工作相关的任务。如果在家庭计算机上查看家庭照片，观看视频或阅读新闻意味着有时需要记住长时间或复杂的命令输入，那么很多人都会发现这是一种轻松的方式来花时间。 CLI的价值最明显的例子可能是那些为软件程序和网页设计编写代码的人。 GUI系统使普通用户更容易访问任务，但是当完成相同的任务而不必将一只手从键盘上移开时，将键盘与鼠标或某种触摸屏组合在一起可能非常耗时。编写代码的人知道他们需要包含的命令代码，并且如果没有必要则不想浪费时间指向和点击。手动输入命令还提供GUI接口中的WYSIWYG选项可能无法提供的精度。例如，如果目标是为网页或具有精确宽度和高度（以像素为单位）的软件程序创建元素，则直接输入这些尺寸比尝试绘制元素更快更准确老鼠。
The graphical user interface (GUI; sometimes pronounced “gooey”) is used by most commercially popular computer operating systems and software programs today. It’s the kind of interface that allows users to manipulate elements on the screen using a mouse, a stylus, or even a finger. This kind of interface allows word processing or web design programs, for example, to offer WYSIWYG (what you see is what you get) options. Before GUI systems became popular, command line interface (CLI) systems were the norm. On these systems, users had to input commands using lines of coded text. The commands ranged from simple instructions for accessing files or directories to far more complicated commands that required many lines of code. As you might imagine, GUI systems have made computers far more user-friendly than CLI systems. A computer with a well-designed GUI can be used by almost anybody, regardless of how technically savvy the user might be. Consider the cash management systems, or computerized cash registers, in use in stores and restaurants today. Inputting information is as simple as pressing numbers or images on a touchscreen in order to place orders and calculate payments, whether they be cash, credit, or debit. This process of inputting information is simple, practically anybody can be trained to do it, and the system can store all of the sales data for later analysis in countless ways. Such data collection was far more labor-intensive in the days before GUI interfaces. Imagine trying to browse the web using a CLI system. Instead of pointing and clicking on links to visually stunning websites, users would have to call up text-driven directories of files and perhaps have to remember long, complicated URLs in order to input them manually. It certainly would be possible, and much valuable computing was done when CLI systems dominated the market, but it could be tedious and generally was limited to work-related tasks. If viewing family photos, watching videos, or reading the news on a home computer meant having to memorize sometimes long or complex command inputs, not many people would find that to be a relaxing way to spend their time. Perhaps the most obvious example of CLI’s value is with those who write code for software programs and web designs. GUI systems make tasks more accessible to average users, but combining a keyboard with a mouse or a touchscreen of some sort can be time-consuming when the same task can be accomplished without having to take one’s hands away from the keyboard. Those who write code know the command codes they need to include and don’t want to waste time pointing and clicking if it’s not necessary. Inputting commands manually also offers precision that a WYSIWYG option in a GUI interface might not provide. For example, if the goal is to create an element for a web page or a software program that has a precise width and height in pixels, it can be faster and more accurate to input those dimensions directly than to try and draw the element with a mouse.