The Role of Command-Line Interfaces in Modern Computing - Term Paper Example

The Role of CLI in Modern Computing Table of Contents Introduction 3 2. History of CLI 3 3. CLI Shells and Scripting 3 3 Shells 3 3.2 Shell Scripts 5 4. Usage of CLI 6 4.1 Usage in Operating Systems 6 4.2 Usage in Search Engines 9 4.3 Usage in networking 9 5. GUI versus CLI 10 Merits of CLI 10 Demerits of CLI 11 Merits of GUI 11 Demerits of GUI 11 Conclusion 12 References 12 [1] Gina Trapani. Geek to Live: The command line comeback. 2007. http://lifehacker.com/226223/geek-to-live--the-command-line-comeback 13 [2] Wikimedia Foundation, Inc. Command-line interface. 13 [3] Wikimedia Foundation, Inc. Command-line interpreter. 13 [4] Wikimedia Foundation, Inc. Shell script. 13 [5] Don Norman. UI Breakthrough-Command Line Interfaces. 2004. 13 [6] Kevin Purdy. Top 10 Command Line Tools. 2008 13 [7] Wikimedia Foundation, Inc.ifconfig. 13 [10] Wikimedia Foundation, Inc. Windows PowerShell 13 1. Introduction Command Line Interfaces (CLI) – A thing of the past? Think again. Command line interfaces are back in the world of computing, equipped with a more comprehensive set of features. Many people might claim that they do not use this modern aspect of computing but in reality they do it everyday, without the realization that they are using CLI. [1] CLI can be termed as a single input box that can execute complex operations based on what you type there. It is a mechanism for interacting with the operating system or software through a type box. Many applications of CLI are found in modern computing for e.g. search box present in the search engines, some operating systems have a command box; anything the user types will get instant action etc. 2. History of CLI [2] The CLI of concept was first conceived to be used with teletype machines in the 1950s. Teletype machines were connected to the big sized computers, and offered results on user’s request. This enabled the users to get faster results from the computer, instead of the batch processing by the punch card input technology. After some time, Graphical terminals were invented which enhanced the visual display of the information. Due to the advancement in modern computing; nowadays personal computers encapsulate all of these three features; CLI, GUI and batch processing. After some years, the users were introduced to a new form of interfacing, GUI. It allowed the users to interact with the computer in ways other than typing. It offered visual icons and indicators to do the job rather than text boxes. It was a reaction to the steep learning curve of CLI; since the usage of CLI required learning all the possible commands it offered. Due to this, CLI was easily forgotten and GUI invaded the computer screens. The constant advancement in the modern computing now offers systems that are equipped with both of these technologies; GUI and CLI. Therefore, users can perform operations in whichever way their requirements are met more efficiently. 3. CLI Shells and Scripting 3.1 Shells A shell can be defined as a software that offers an interface to a user. The shells mainly fall in two categories; command-line and graphical. Command-line provides a CLI to the users whereas graphical offers a GUI. In both of these interfaces, the primary function in the operating system is to launch another program. It has an additional capability of viewing contents in directories. It is often debated as to which category produces better and faster outcome. It is mainly noticed that CLI shells provide faster performance when data transfers and processing is required. On the other hand, GUI is best used for image and video processing and editing etc. [3] Explaining CLI shell further; “A command line shell (also command-line interpreter) is a computer program that reads lines of text entered by a user and interprets them in the context of a given operating system or programming language.” A command line shell enables the user to perform very complex functions by only writing few appropriate commands. Examples of Shells Unix shell is a command interpreter and script host that provides a traditional interface to the UNIX operating system. Examples of Unix Shell programs are sh, Bash, ksh etc. Fig. 1: Screenshot of Bash program Windows Powershell It is an automation engine from Microsoft, that consists of a command-line shell and scripting language. Fig.2: Screenshot of a Windows Powershell session 3.2 Shell Scripts [4] A shell script is a script that is written for the command-line interpreter. A language is used to write these scripts, which is called the scripting language; scripting language is a programming language that gives control of one or more software applications. Common operations that are performed by shell scripts include file manipulation, program execution and printing text. Shell scripts allow commands to be executed automatically rather than being entered manually. For example, the following Bourne shell script copies all text files (*.txt) and MP3 files (*.mp3) in the working directory to the root directory: cp *.txt / cp *.mp3 / 4. Usage of CLI Command line interpreter allows scripts to run on them; in which a wide range of commands can be executed on a large number of data. CLI are also very useful to people with visual disability, as the commands and feedbacks can be displayed using Refreshable Braille displays. 4.1 Usage in Operating Systems Macintosh operating system has released some latest versions that are based on the variation of Unix called Darwin. The users of these computers are provided with a Unix-like command-line interface called Terminal. [6] When something is desired to be performed quickly and efficiently without any overhead by the software, then command line is the best way to go. Due to the evolution of the graphical interface, command line or terminal have become an insider’s secret weapon. However, people who know how to get work done from CLI commands, do wonders with its virtues. Nested folders is a common approach to organize music, pictures, documents, or other media. Right-clicking in GUI and choosing “New Folder”, then naming and clicking through each of "The Beatles->White Album->Disc 1" seems like an ordeal. Its far easier from the command line: mkdir The Beatles\White Album\Disc 1 Windows Operating system [8] Windows is famous for its easy to use GUI, therefore users tend to forget or have never known that there are many powerful tools for command line encapsulated in it. There are two basic features involving a command line; one is the entry “Run” and the other is the command prompt window. Fig. 3: Screenshot of command prompt in Windows XP Apple and Microsoft are now both equipped with the search feature integrated into their operating system. The search feature has a rich command line format, therefore to find a document in Microsoft Vista; the following command will be entered in the search bar: Fig.4: Search box in Microsoft Vista “command line folder:interactions type:doc” This request will search all the Microsoft Word files in any of the folders on the system which have the word “interactions” in the folder name and the words “command line” in the contents or title. CLI has been implemented in the following areas in Windows, with examples of each: File management assoc This tool is very useful for managing the relationship or association between file extensions and file types. The syntax is: assoc [.ext[=[fileType]]] Networking and Internet tools Net accounts - Updates the user accounts database and modifies password and logon requirements for all accounts. Net computer - Adds or deletes computers from a domain database System administration and maintenance Windows XP Professional comes with a powerful command-line tool called Tasklist that provides many details on the programs and processes that are running; it is known to give more detailed information than the Task Manager Unix CLI Macintosh operating system has released some latest versions that are based on the variation of Unix called Darwin. The users of these computers are provided with a Unix-like command-line interface called Terminal. Fig.5: Unix CLIX Unix is equipped with many features to handle key functions of the operating system, some are: Disk Management  Check a RAID set for errors.  Show free disk space.  Show fixed disk info.  Show disk usage statistics.  Enable, disable disk journaling.  Verify, repair volume structures. Log Management  View CUPS access log.  View CUPS error log.  View console log.  View system log. Network Management  Show network I/O in real-time.  Show network status of routing tables.  Show network status per process.  Show number of dropped packets. 4.2 Usage in Search Engines [5] With the efficient and modern usage of CLI, the search engines have become answer engines. Typically, we write the search items in the search boxes on the search engines. However, since the implication of CLI in the engines we can write commands to yield answers without the need to go to an intermediate webpage. All major search engines provide this feature. For example; Google: the phrase “define:victory” directly provides the definition. Yahoo!: the phrase “time in Pakistan” directly provides the time. Similar function is offered by Google for the local computer with Google Desktop. If the control button is hit twice; GDesktop search box appears and all the advanced operator’s Googles web search product offers are available for service. 4.3 Usage in networking [8] The command prompt is preferably used by system administrators; therefore many of the commands are specialized for administration and networking. A suite of command line networking tools called Netsh; comes with its own shell or interface is contained in a number of Windows operating systems. Netstat is another useful tool for checking network and Internet connections. There are many uses of command line in networking. Some of them are discussed in this section: [7] ifconfig (short for interface configurator) is a system administration utility in Unix-like operating systems. It is used to configure, control, and query TCP/IP network interface parameters from a command line interface (CLI) or in system configuration scripts. Common uses for ifconfig include setting an interfaces IP address and netmask, and disabling or enabling a given interface. Few other examples of network management are given below;  Net send- Sends a messenger service message  Net session- Lists or disconnects sessions  Net share- Displays or manages shared printers or directories  Net start- Lists or starts network services  Net statistics- Displays workstation and server statistics  Net stop- Stops services  Net time- Displays or synchronizes network time  Net use- Displays or manages remote connections  Net user- Creates local user accounts  Net view- Displays network resources or computers 5. GUI versus CLI There are different school of thoughts regarding the debate of which interface is better and more convenient to the user. Here are some of the key factors of their comparison with each other: Merits of CLI Command line allows useful or complex commands to be saved for later use. They can be saved by assigning a character string or alias to represent the full command or several commands can be grouped to perform a more complex sequence. For instance; compile the program, install it, and run it; creating a single entity, called a command procedure or script which itself can be treated as a command. These advantages mean that a user figures out a complex command only once, since they can be saved, to be used again. CLI gives the user more control and options to be performed simply by typing it. Using CLI is faster. Only a keyboard is needed by the user; rather than switching their hands between the keyboard and the mouse. Typing has always known to be a faster mode than clicking. It saves the individual from the scrolling, clicking and nested windows. Demerits of CLI Users have grown accustomed to the colorful interface and feel that the black dark screen is a thing of the past. Users tend to take some time in getting acquainted with the commands and environment that it offers; therefore prefer switching to other interfaces. Merits of GUI Using GUI is faster. Picking and choosing icons is preferred by many users, instead of memorizing commands for all functions. GUI is best at editing images or video or development of data etc. GUI has an advantage of being able to run multiple processes at a single time with the the end user knowing and keeping track of all of them. It allows an easier level of operation for a new computer user. Demerits of GUI GUI is said to consume too much CPU and memory in some operating systems. Some users find the nested windows and numerous clicking to be hassle. A metaphor that explain the difference between their usage: [6] “The difference between taking the main roads across town instead of back roads may be that the main roads are easier—but take longer. However, if you drive across town every day, its worth your time learning the back road shortcuts.” The GUI is the "main road" from point A to point B: its obvious and easy to describe and intuit, but it takes longer. The CLI takes longer to learn, but will get you there in less time. Conclusion CLI has made a commendable comeback in the modern world of computing and never ceases to amaze an individual of its capabilities and power. It has become more robust and fault tolerant than the ones in the past. This concept of ‘entering’ a command saves the time spent in clicking and scrolling the mouse and can perform functions as fast as one can type. It serves to be an excellent medium for administration of systems and networks because of its diverse set of commands. I have found it exceptionally efficient in this area as it speeds the process of managing networks across different system. It also offers a list of security features that helps in making the network reliable and secure. The implication of CLI in the search engines has also made searching easier and more accurate. One might argue that a search box is not a command line but it is a text box in which complex commands can be performed. For example the following lines of command will yield music files that have ‘Beatles’ word in their link: -inurl :(htm|html|php) intitle:"index of" +"last modified" +"parent directory" +description +size + (wma|mp3) "Beatles" My personal experience with Windows Powershell has been informative and reliable. PowerShell also provide an interactive command line interface, wherein the commands can be entered and their output displayed. The user interface, based on the Win32 console. One feature that I have found very useful is that of a pipeline. Like Unix pipelines, PowerShell pipelines are used to compose complex commands, allowing the output of one command to be passed as input to another. [10] Powershell also supports both named and positional parameters for commands. When executing a script, the job of binding the argument value to the parameter is done by PowerShell itself. References [1] Gina Trapani. Geek to Live: The command line comeback. 2007. http://lifehacker.com/226223/geek-to-live--the-command-line-comeback [2] Wikimedia Foundation, Inc. Command-line interface. http://en.wikipedia.org/wiki/Command-line_interface [3] Wikimedia Foundation, Inc. Command-line interpreter. http://en.wikipedia.org/wiki/Command-line_interpreter [4] Wikimedia Foundation, Inc. Shell script. http://en.wikipedia.org/wiki/Shell_script [5] Don Norman. UI Breakthrough-Command Line Interfaces. 2004. http://www.jnd.org/dn.mss/ui_breakthroughcomma.html [6] Kevin Purdy. Top 10 Command Line Tools. 2008 http://lifehacker.com/399468/top-10-command-line-tools [7] Wikimedia Foundation, Inc.ifconfig. http://en.wikipedia.org/wiki/Ifconfig [8] Victor Laurie. The Windows Command Line, Batch Files, and Scripting. http://commandwindows.com/ [9] http://hackydev.ics.hawaii.edu/hackyDevSite/external/docbook/ch26s07.htm [10] Wikimedia Foundation, Inc. Windows PowerShell http://www.answers.com/topic/windows-powershell Read More