94-541: Command Prompt , also known as cmd.exe or cmd , is the default command-line interpreter for the OS/2 , eComStation , ArcaOS , Microsoft Windows ( Windows NT family and Windows CE family ), and ReactOS operating systems. On Windows CE .NET 4.2 , Windows CE 5.0 and Windows Embedded CE 6.0 it is referred to as the Command Processor Shell . Its implementations differ between operating systems, but
188-486: A computer program by inputting lines of text called command-lines . Command-line interfaces emerged in the mid-1960s, on computer terminals , as an interactive and more user-friendly alternative to the non-interactive interface available with punched cards . Today, most computer users rely on graphical user interfaces ("GUIs") instead of CLIs. However, many programs and operating system utilities lack GUIs, and are intended to be used through CLIs. Knowledge of CLIs
282-509: A field . The first card of a group of cards, containing fixed or indicative information for that group, is known as a master card . Cards that are not master cards are detail cards . The Hollerith punched cards used for the 1890 U.S. census were blank. Following that, cards commonly had printing such that the row and column position of a hole could be easily seen. Printing could include having fields named and marked by vertical lines, logos, and more. "General purpose" layouts (see, for example,
376-519: A flag or switch ) modifies the operation of a command; the effect is determined by the command's program. Options follow the command name on the command line, separated by spaces. A space before the first option is not always required, such as Dir/? and DIR /? in DOS, which have the same effect of listing the DIR command's available options, whereas dir --help (in many versions of Unix) does require
470-438: A mouse pointer , such as Microsoft Windows ), text-based user interface menus (such as DOS Shell and IBM AIX SMIT ), and keyboard shortcuts . Compared with a graphical user interface, a command-line interface requires fewer system resources to implement. Since options to commands are given in a few characters in each command line, an experienced user often finds the options easier to access. Automation of repetitive tasks
564-440: A penny column represents the values zero through eleven; 10 (top), 11, then 0 through 9 as above. An arithmetic sign can be punched in the adjacent shilling column. Zone punches had other uses in processing, such as indicating a master card. Diagram: Note: The 11 and 12 zones were also called the X and Y zones, respectively. In 1931, IBM began introducing upper-case letters and special characters (Powers-Samas had developed
658-478: A pipeline where the output of one command becomes the input to the next command. One can modify the set of available commands by modifying which paths appear in the PATH environment variable. Under Unix, commands also need be marked as executable files. The directories in the path variable are searched in the order they are given. By re-ordering the path, one can run e.g. \OS2\MDOS\E.EXE instead of \OS2\E.EXE, when
752-438: A CLI, presenting their own prompt to the user and accepting command lines. Other programs support both a CLI and a GUI. In some cases, a GUI is simply a wrapper around a separate CLI executable file . In other cases, a program may provide a CLI as an optional alternative to its GUI. CLIs and GUIs often support different functionality. For example, all features of MATLAB , a numerical analysis computer program, are available via
846-458: A Unix-like CLI. Microsoft provides MKS Inc. 's ksh implementation MKS Korn shell for Windows through their Services for UNIX add-on. Since 2001, the Macintosh operating system macOS has been based on a Unix-like operating system called Darwin . On these computers, users can access a Unix-like command-line interface by running the terminal emulator program called Terminal , which
940-420: A column are called zone punching positions , 12 (top), 11, and 0 (0 may be either a zone punch or a digit punch). For decimal data the lower ten positions are called digit punching positions , 0 (top) through 9. An arithmetic sign can be specified for a decimal field by overpunching the field's rightmost column with a zone punch: 12 for plus, 11 for minus (CR). For Pound sterling pre-decimalization currency
1034-504: A command procedure or script which itself can be treated as a command. These advantages mean that a user must figure out a complex command or series of commands only once, because they can be saved, to be used again. The commands given to a CLI shell are often in one of the following forms: where doSomething is, in effect, a verb , how an adverb (for example, should the command be executed verbosely or quietly ) and toFiles an object or objects (typically one or more files) on which
SECTION 10
#17328026152681128-435: A fast, accurate means of manually punching holes in specially scored IBM punched cards. Designed to fit in the pocket, Port-A-Punch made it possible to create punched card documents anywhere. The product was intended for "on-the-spot" recording operations—such as physical inventories, job tickets and statistical surveys—because it eliminated the need for preliminary writing or typing of source documents. In 1969 IBM introduced
1222-513: A magnetic tape encoder in 1965, a system marketed as a keypunch replacement which was somewhat successful. Punched cards were still commonly used for entering both data and computer programs until the mid-1980s when the combination of lower cost magnetic disk storage , and affordable interactive terminals on less expensive minicomputers made punched cards obsolete for these roles as well. However, their influence lives on through many standard conventions and file formats. The terminals that replaced
1316-597: A method of recording and playing back performances on a harmonium using punched cards. The system was called the Mélographe Répétiteur and "writes down ordinary music played on the keyboard dans le langage de Jacquard", that is as holes punched in a series of cards. By 1887 Carpentier had separated the mechanism into the Melograph which recorded the player's key presses and the Melotrope which played
1410-475: A new, smaller, round-hole, 96-column card format along with the IBM System/3 low-end business computer. These cards have tiny, 1 mm diameter circular holes, smaller than those in paper tape . Data is stored in 6-bit BCD , with three rows of 32 characters each, or 8-bit EBCDIC . In this format, each column of the top tiers are combined with two punch rows from the bottom tier to form an 8-bit byte, and
1504-484: A pair are formed by combining that punch with a 9 punch. Alphabetic and special characters use 3 or more punches. The British Powers-Samas company used a variety of card formats for their unit record equipment . They began with 45 columns and round holes. Later 36, 40 and 65 column cards were provided. A 130 column card was also available – formed by dividing the card into two rows, each row with 65 columns and each character space with 5 punch positions. A 21 column card
1598-467: A powerful tool for business data-processing. By 1950 punched cards had become ubiquitous in industry and government. "Do not fold, spindle or mutilate," a warning that appeared on some punched cards distributed as documents such as checks and utility bills to be returned for processing, became a motto for the post- World War II era. In 1956 IBM signed a consent decree requiring, amongst other things, that IBM would by 1962 have no more than one-half of
1692-588: A pure GUI. This is typically the case with operating system command shells . CLIs are also used by systems with insufficient resources to support a graphical user interface. Some computer language systems (such as Python , Forth , LISP , Rexx , and many dialects of BASIC ) provide an interactive command-line mode to allow for rapid evaluation of code. CLIs are often used by programmers and system administrators, in engineering and scientific environments, and by technically advanced personal computer users. CLIs are also popular among people with visual disabilities since
1786-586: A service and that the cards were part of the machine. IBM fought all the way to the Supreme Court and lost in 1936; the court ruled that IBM could only set card specifications. "By 1937... IBM had 32 presses at work in Endicott, N.Y., printing, cutting and stacking five to 10 million punched cards every day." Punched cards were even used as legal documents, such as U.S. Government checks and savings bonds. During World War II punched card equipment
1880-478: A variety of punched cards and unit record machines for creating, sorting, and tabulating punched cards, even after the development of electronic computers in the 1950s. Both IBM and Remington Rand tied punched card purchases to machine leases, a violation of the US 1914 Clayton Antitrust Act . In 1932, the US government took both to court on this issue. Remington Rand settled quickly. IBM viewed its business as providing
1974-670: Is 12 only, "-" is 11 only, and "/" is 0 + 1). The Space character has no punches. The information represented in a column by a combination of zones [12, 11, 0] and digits [0–9] is dependent on the use of that column. For example, the combination "12-1" is the letter "A" in an alphabetic column, a plus signed digit "1" in a signed numeric column, or an unsigned digit "1" in a column where the "12" has some other use. The introduction of EBCDIC in 1964 defined columns with as many as six punches (zones [12,11,0,8,9] + digit [1–7]). IBM and other manufacturers used many different 80-column card character encodings . A 1969 American National Standard defined
SECTION 20
#17328026152682068-415: Is a piece of card stock that stores digital data using punched holes. Punched cards were once common in data processing and the control of automated machines . Punched cards were widely used in the 20th century, where unit record machines , organized into data processing systems , used punched cards for data input, output, and storage. The IBM 12-row/80-column punched card format came to dominate
2162-513: Is active a program is typically invoked by typing its name followed by command-line arguments (if any). For example, in Unix and Unix-like environments, an example of a command-line argument is: file.s is a command-line argument which tells the program rm to remove the file named file.s . Some programming languages, such as C , C++ and Java , allow a program to interpret the command-line arguments by handling them as string parameters in
2256-415: Is also useful for writing scripts . Programs that have CLIs are generally easy to automate via scripting, since command-lines, being mere lines of text, are easy to specify in code. CLIs are made possible by command-line interpreters or command-line processors , which are programs that read command-lines and carry out the commands. Alternatives to CLIs include GUIs (most notably desktop metaphors with
2350-401: Is available as an external command stored in \Windows\net.exe . The ReactOS implementation includes the following internal commands: On Windows, cmd.exe is mostly compatible with COMMAND.COM but provides the following extensions over it: Internal commands have also been improved: Command-line interpreter A command-line interface ( CLI ) is a means of interacting with
2444-549: Is called a stub card . 80-column cards were available scored, on either end, creating both a short card and a stub card when torn apart. Short cards can be processed by other IBM machines. A common length for stub cards was 51 columns. Stub cards were used in applications requiring tags, labels, or carbon copies. According to the IBM Archive: IBM's Supplies Division introduced the Port-A-Punch in 1958 as
2538-510: Is derived from FreeCOM, the FreeDOS command line interpreter. cmd.exe interacts with the user through a command-line interface . On Windows, this interface is implemented through the Win32 console . cmd.exe may take advantage of features available to native programs of its own platform. For example, on OS/2 and Windows, it can use real pipes in command pipelines, allowing both sides of
2632-600: Is found in the Utilities sub-folder of the Applications folder, or by remotely logging into the machine using ssh . Z shell is the default shell for macOS; Bash, tcsh , and the KornShell are also provided. Before macOS Catalina , Bash was the default. A CLI is used whenever a large vocabulary of commands or queries, coupled with a wide (or arbitrary) range of options, can be entered more rapidly as text than with
2726-406: Is simplified by line editing and history mechanisms for storing frequently used sequences; this may extend to a scripting language that can take parameters and variable options. A command-line history can be kept, allowing review or repetition of commands. A command-line system may require paper or online manuals for the user's reference, although often a help option provides a concise review of
2820-516: Is the grammar that all commands must follow. In the case of operating systems , DOS and Unix each define their own set of rules that all commands must follow. In the case of embedded systems , each vendor, such as Nortel , Juniper Networks or Cisco Systems , defines their own proprietary set of rules. These rules also dictate how a user navigates through the system of commands. The semantics define what sort of operations are possible, on what sort of data these operations can be performed, and how
2914-459: The IBM 701 and IBM 704 , card data was read, using an IBM 711 , into memory in row binary format. For each of the twelve rows of the card, 72 of the 80 columns, skipping the other eight, would be read into two 36-bit words, requiring 864 bits to store the whole card; a control panel was used to select the 72 columns to be read. Software would translate this data into the desired form. One convention
cmd.exe - Misplaced Pages Continue
3008-476: The main function . Other languages, such as Python , expose operating system specific API (functionality) through sys module , and in particular sys.argv for command-line arguments . In Unix-like operating systems , a single hyphen used in place of a file name is a special value specifying that a program should handle data coming from the standard input or send data to the standard output . A command-line option or simply option (also known as
3102-531: The pantograph "keyboard punch". It featured an enlarged diagram of the card, indicating the positions of the holes to be punched. A printed reading board could be placed under a card that was to be read manually. Hollerith envisioned a number of card sizes. In an article he wrote describing his proposed system for tabulating the 1890 U.S. census , Hollerith suggested a card 3 by 5 + 1 ⁄ 2 inches (7.6 by 14.0 cm) of Manila stock "would be sufficient to answer all ordinary purposes." The cards used in
3196-514: The 1890 census had round holes, 12 rows and 24 columns. A reading board for these cards can be seen at the Columbia University Computing History site. At some point, 3 + 1 ⁄ 4 by 7 + 3 ⁄ 8 inches (83 by 187 mm) became the standard card size. These are the dimensions of the then-current paper currency of 1862–1923. This size was needed in order to use available banking-type storage for
3290-789: The 1920s they had units for carrying out basic arithmetic operations. Hollerith founded the Tabulating Machine Company (1896) which was one of four companies that were amalgamated via stock acquisition to form a fifth company, Computing-Tabulating-Recording Company (CTR) in 1911, later renamed International Business Machines Corporation (IBM) in 1924. Other companies entering the punched card business included The Tabulator Limited (Britain, 1902), Deutsche Hollerith-Maschinen Gesellschaft mbH (Dehomag) (Germany, 1911), Powers Accounting Machine Company (US, 1911), Remington Rand (US, 1927), and H.W. Egli Bull (France, 1931). These companies, and others, manufactured and marketed
3384-422: The 60,000,000 punched cards to come nationwide. Hollerith's original system used an ad hoc coding system for each application, with groups of holes assigned specific meanings, e.g. sex or marital status. His tabulating machine had up to 40 counters, each with a dial divided into 100 divisions, with two indicator hands; one which stepped one unit with each counting pulse, the other which advanced one unit every time
3478-533: The CLI, whereas the MATLAB GUI exposes only a subset of features. In Colossal Cave Adventure from 1975, the user uses a CLI to enter one or two words to explore a cave system. The command-line interface evolved from a form of communication conducted by people over teleprinter (TTY) machines. Sometimes these involved sending an order or a confirmation using telex . Early computer systems often used teleprinter as
3572-717: The Hollerith Tabulating Machine to Brown's Tables of the Moon . By the late 1920s, customers wanted to store more data on each punched card. Thomas J. Watson Sr. , IBM's head, asked two of his top inventors, Clair D. Lake and J. Royden Pierce , to independently develop ways to increase data capacity without increasing the size of the punched card. Pierce wanted to keep round holes and 45 columns but to allow each column to store more data; Lake suggested rectangular holes, which could be spaced more tightly, allowing 80 columns per punched card, thereby nearly doubling
3666-450: The IBM 5081 below) were also available. For applications requiring master cards to be separated from following detail cards, the respective cards had different upper corner diagonal cuts and thus could be separated by a sorter. Other cards typically had one upper corner diagonal cut so that cards not oriented correctly, or cards with different corner cuts, could be identified. Herman Hollerith
3760-524: The PC's serial ports . These were typically used to interface an organization's new PC's with their existing mini- or mainframe computers, or to connect PC to PC. Some of these PCs were running Bulletin Board System software. Early operating system CLIs were implemented as part of resident monitor programs, and could not easily be replaced. The first implementation of the shell as a replaceable component
3854-498: The Windows CMD.EXE programs, the latter groups being based heavily on DEC's RSX-11 and RSTS CLIs. Under most operating systems, it is possible to replace the default shell program with alternatives; examples include 4DOS for DOS, 4OS2 for OS/2, and 4NT / Take Command for Windows. Although the term 'shell' is often used to describe a command-line interpreter, strictly speaking, a 'shell' can be any program that constitutes
cmd.exe - Misplaced Pages Continue
3948-498: The behavior and basic set of commands are consistent. cmd.exe is the counterpart of COMMAND.COM in DOS and Windows 9x systems, and analogous to the Unix shells used on Unix-like systems. The initial version of cmd.exe for Windows NT was developed by Therese Stowell. Windows CE 2.11 was the first embedded Windows release to support a console and a Windows CE version of cmd.exe . The ReactOS implementation of cmd.exe
4042-544: The capacity of the older format. Watson picked the latter solution, introduced as The IBM Card , in part because it was compatible with existing tabulator designs and in part because it could be protected by patents and give the company a distinctive advantage. This IBM card format, introduced in 1928, has rectangular holes, 80 columns, and 10 rows. Card size is 7 + 3 ⁄ 8 by 3 + 1 ⁄ 4 inches (187 by 83 mm). The cards are made of smooth stock, 0.007 inches (180 μm) thick. There are about 143 cards to
4136-425: The card. IBM's Fred M. Carroll developed a series of rotary presses that were used to produce punched cards, including a 1921 model that operated at 460 cards per minute (cpm). In 1936 he introduced a completely different press that operated at 850 cpm. Carroll's high-speed press, containing a printing cylinder, revolutionized the company's manufacturing of punched cards. It is estimated that between 1930 and 1950,
4230-423: The command In zsh the $ RPROMPT variable controls an optional prompt on the right-hand side of the display. It is not a real prompt in that the location of text entry does not change. It is used to display information on the same line as the prompt, but right-justified. In RISC OS the command prompt is a * symbol, and thus (OS) CLI commands are often referred to as star commands . One can also access
4324-670: The command line interface as the primary user interface replaced by the Graphical User Interface . The command line remained available as an alternative user interface, often used by system administrators and other advanced users for system administration, computer programming and batch processing . In November 2006, Microsoft released version 1.0 of Windows PowerShell (formerly codenamed Monad ), which combined features of traditional Unix shells with their proprietary object-oriented .NET Framework . MinGW and Cygwin are open-source packages for Windows that offer
4418-399: The command should act. The > in the third example is a redirection operator , telling the command-line interpreter to send the output of the command not to its own standard output (the screen) but to the named file. This will overwrite the file. Using >> will redirect the output and append it to the file. Another redirection operator is the vertical bar ( | ), which creates
4512-431: The commands and responses can be displayed using refreshable Braille displays . The general pattern of a command line interface is: In this format, the delimiters between command-line elements are whitespace characters and the end-of-line delimiter is the newline delimiter. This is a widely used (but not universal) convention. A CLI can generally be considered as consisting of syntax and semantics . The syntax
4606-410: The corresponding information into the card. Aperture cards have a cut-out hole on the right side of the punched card. A piece of 35 mm microfilm containing a microform image is mounted in the hole. Aperture cards are used for engineering drawings from all engineering disciplines. Information about the drawing, for example the drawing number, is typically punched and printed on the remainder of
4700-407: The current time, user, shell number or working directory) in order, for instance, to make the prompt more informative or visually pleasing, to distinguish sessions on various machines, or to indicate the current level of nesting of commands. On some systems, special tokens in the definition of the prompt can be used to cause external programs to be called by the command-line interpreter while displaying
4794-422: The default is the opposite. Renaming of the executables also works: people often rename their favourite editor to EDIT, for example. The command line allows one to restrict available commands, such as access to advanced internal commands. The Windows CMD.EXE does this. Often, shareware programs will limit the range of commands, including printing a command 'your administrator has disabled running batch files' from
SECTION 50
#17328026152684888-501: The features that are commonly considered to produce structured programs. The Bourne shell led to the development of the KornShell (ksh), Almquist shell (ash), and the popular Bourne-again shell (or Bash). Early microcomputers themselves were based on a command-line interface such as CP/M , DOS or AppleSoft BASIC . During the 1980s and 1990s, the introduction of the Apple Macintosh and of Microsoft Windows on PCs saw
4982-506: The first Multics shell was developed by Glenda Schroeder . The first Unix shell , the V6 shell , was developed by Ken Thompson in 1971 at Bell Labs and was modeled after Schroeder's Multics shell. The Bourne shell was introduced in 1977 as a replacement for the V6 shell. Although it is used as an interactive command interpreter, it was also intended as a scripting language and contains most of
5076-436: The first commercial alphabetic punched card representation in 1921). The 26 letters have two punches (zone [12,11,0] + digit [1–9]). The languages of Germany, Sweden, Denmark, Norway, Spain, Portugal and Finland require up to three additional letters; their punching is not shown here. Most special characters have two or three punches (zone [12,11,0, or none] + digit [2–7] + 8); a few special characters were exceptions: "&"
5170-464: The following special characters : and white space. The following is a list of the Microsoft OS/2 internal cmd.exe commands : The following list of internal commands is supported by cmd.exe on Windows NT and later: The following list of commands is supported by cmd.exe on Windows CE .NET 4.2, Windows CE 5.0 and Windows Embedded CE 6.0: In addition, the net command
5264-399: The following commands to execute. For example: In the above example, CommandB will only execute if CommandA completes successfully, and the execution of CommandC depends on the successful completion of CommandB . To process subsequent commands even if the previous command produces an error, the command separator & should be used. For example: On Windows XP or later,
5358-412: The grammar represents these operations and data—the symbolic meaning in the syntax. Two different CLIs may agree on either syntax or semantics, but it is only when they agree on both that they can be considered sufficiently similar to allow users to use both CLIs without needing to learn anything, as well as to enable re-use of scripts. A simple CLI will display a prompt, accept a command line typed by
5452-451: The inch (56/cm). In 1964, IBM changed from square to round corners. They come typically in boxes of 2,000 cards or as continuous form cards. Continuous form cards could be both pre-numbered and pre-punched for document control (checks, for example). Initially designed to record responses to yes–no questions , support for numeric, alphabetic and special characters was added through the use of columns and zones. The top three positions of
5546-468: The industry. Many early digital computers used punched cards as the primary medium for input of both computer programs and data . Data can be entered onto a punched card using a keypunch . While punched cards are now obsolete as a storage medium , as of 2012, some voting machines still used punched cards to record votes. Punched cards also had a significant cultural impact in the 20th century. The idea of control and data storage via punched holes
5640-501: The interface mode. At this point, commands from the system mode may not be accessible until the user exits the interface mode and enters the system mode. A command prompt (or just prompt ) is a sequence of (one or more) characters used in a command-line interface to indicate readiness to accept commands. It literally prompts the user to take action. A prompt usually ends with one of the characters $ , % , # , : , > or - and often includes other information, such as
5734-411: The maximum length of the string that can be used at the command prompt is 8191 (2-1) characters. On earlier versions, such as Windows 2000 or Windows NT 4.0 , the maximum length of the string is 2047 (2-1) characters. This limit includes the command line, individual environment variables that are inherited by other processes , and all environment variable expansions. Quotation marks are required for
SECTION 60
#17328026152685828-598: The means of interaction with an operator. The mechanical teleprinter was replaced by a "glass tty" , a keyboard and screen emulating the teleprinter. "Smart" terminals permitted additional functions, such as cursor movement over the entire screen, or local editing of data on the terminal for transmission to the computer. As the microcomputer revolution replaced the traditional – minicomputer + terminals – time sharing architecture, hardware terminals were replaced by terminal emulators — PC software that interpreted terminal signals sent through
5922-565: The mechanism. In 1804 Joseph Marie Jacquard demonstrated a mechanism to automate loom operation. A number of punched cards were linked into a chain of any length. Each card held the instructions for shedding (raising and lowering the warp ) and selecting the shuttle for a single pass. Semyon Korsakov was reputedly the first to propose punched cards in informatics for information store and search. Korsakov announced his new method and machines in September 1832. Charles Babbage proposed
6016-459: The middle tier is combined with two more punch rows, so that each card contains 64 bytes of 8-bit-per-byte binary coded data. As in the 80 column card, readable text was printed in the top section of the card. There was also a 4th row of 32 characters that could be printed. This format was never widely used; it was IBM-only, but they did not support it on any equipment beyond the System/3, where it
6110-435: The most common punched card formats is the IBM 5081 card format, a general purpose layout with no field divisions. This format has digits printed on it corresponding to the punch positions of the digits in each of the 80 columns. Other punched card vendors manufactured cards with this same layout and number. Long cards were available with a scored stub on either end which, when torn off, left an 80 column card. The torn off card
6204-426: The multifunction unit 3525 used a different encoding scheme for column binary data, also known as card image , where each column, split into two rows of 6 (12–3 and 4–9) was encoded into two 8-bit bytes, holes in each group represented by bits 2 to 7 (MSb numbering , bit 0 and 1 unused ) in successive bytes. This required 160 8-bit bytes, or 1280 bits, to store the whole card. As an aid to humans who had to deal with
6298-443: The music. At the end of the 1800s Herman Hollerith created a method for recording data on a medium that could then be read by a machine, developing punched card data processing technology for the 1890 U.S. census . His tabulating machines read and summarized data stored on punched cards and they began use for government and commercial data processing. Initially, these electromechanical machines only counted holes, but by
6392-461: The newer C:\> style, unless used on floppy drives A: or B:; on those systems PROMPT $ N$ G can be used to override the automatic default and explicitly switch to the older style. Many Unix systems feature the $ PS1 variable (Prompt String 1), although other variables also may affect the prompt (depending on the shell used). In the Bash shell, a prompt of the form: could be set by issuing
6486-436: The number of character positions available, e.g. 80-column card . A sequence of cards that is input to or output from some step in an application's processing is called a card deck or simply deck . The rectangular, round, or oval bits of paper punched out were called chad ( chads ) or chips (in IBM usage). Sequential card columns allocated for a specific use, such as names, addresses, multi-digit numbers, etc., are known as
6580-465: The operating system. A program that implements such a text interface is often called a command-line interpreter, command processor or shell . Examples of command-line interpreters include Nushell , DEC's DIGITAL Command Language (DCL) in OpenVMS and RSX-11 , the various Unix shells ( sh , ksh , csh , tcsh , zsh , Bash , etc.), CP/M 's CCP , DOS ' COMMAND.COM , as well as the OS/2 and
6674-525: The option to be preceded by at least one space (and is case-sensitive). The format of options varies widely between operating systems. In most cases the syntax is by convention rather than an operating system requirement; the entire command line is simply a string passed to a program, which can process it in any way the programmer wants, so long as the interpreter can tell where the command name ends and its arguments and options begin. Punched cards A punched card (also punch card or punched-card )
6768-462: The options of a command. The command-line environment may not provide graphical enhancements such as different fonts or extended edit windows found in a GUI. It may be difficult for a new user to become familiar with all the commands and options available, compared with the icons and drop-down menus of a graphical user interface, without reference to manuals. Operating system (OS) command-line interfaces are usually distinct programs supplied with
6862-578: The other dial made a complete revolution. This arrangement allowed a count up to 9,999. During a given tabulating run counters were assigned specific holes or, using relay logic , combination of holes. Later designs led to a card with ten rows, each row assigned a digit value, 0 through 9, and 45 columns. This card provided for fields to record multi-digit numbers that tabulators could sum, instead of their simply counting cards. Hollerith's 45 column punched cards are illustrated in Comrie 's The application of
6956-468: The path of the current working directory and the hostname . On many Unix and derivative systems , the prompt commonly ends in $ or % if the user is a normal user, but in # if the user is a superuser ("root" in Unix terminology). End-users can often modify prompts. Depending on the environment, they may include colors, special characters, and other elements (like variables and functions for
7050-457: The pipeline to run concurrently. As a result, it is possible to redirect the standard error stream . ( COMMAND.COM uses temporary files, and runs the two sides serially, one after the other.) Multiple commands can be processed in a single command line using the command separator && . When using this separator in the Windows cmd.exe , each command must complete successfully for
7144-428: The prompt. Some CLIs, such as those in network routers , have a hierarchy of modes , with a different set of commands supported in each mode. The set of commands are grouped by association with security, system, interface, etc. In these systems the user might traverse through a series of sub-modes. For example, if the CLI had two modes called interface and system , the user might use the command interface to enter
7238-548: The prompt. In DOS' COMMAND.COM and in Windows NT's cmd.exe users can modify the prompt by issuing a PROMPT command or by directly changing the value of the corresponding %PROMPT% environment variable . The default of most modern systems, the C:\>; style is obtained, for instance, with PROMPT $ P$ G . The default of older DOS systems, C> is obtained by just PROMPT , although on some systems this produces
7332-594: The punched card manufacturing capacity in the United States. Tom Watson Jr.'s decision to sign this decree, where IBM saw the punched card provisions as the most significant point, completed the transfer of power to him from Thomas Watson, Sr . The Univac UNITYPER introduced magnetic tape for data entry in the 1950s. During the 1960s, the punched card was gradually replaced as the primary means for data storage by magnetic tape , as better, more capable computers became available. Mohawk Data Sciences introduced
7426-632: The punched cards, the IBM 3270 for example, displayed 80 columns of text in text mode , for compatibility with existing software. Some programs still operate on the convention of 80 text columns, although fewer and fewer do as newer systems employ graphical user interfaces with variable-width type fonts. The terms punched card , punch card , and punchcard were all commonly used, as were IBM card and Hollerith card (after Herman Hollerith ). IBM used "IBM card" or, later, "punched card" at first mention in its documentation and thereafter simply "card" or "cards". Specific formats were often indicated by
7520-508: The punched cards, the IBM 026 and later 029 and 129 key punch machines could print human-readable text above each of the 80 columns. As a prank, punched cards could be made where every possible punch position had a hole. Such " lace cards " lacked structural strength, and would frequently buckle and jam inside the machine. The IBM 80-column punched card format dominated the industry, becoming known as just IBM cards , even though other companies made cards and equipment to process them. One of
7614-480: The punches for 128 characters and was named the Hollerith Punched Card Code (often referred to simply as Hollerith Card Code ), honoring Hollerith. For some computer applications, binary formats were used, where each hole represented a single binary digit (or " bit "), every column (or row) is treated as a simple bit field , and every combination of holes is permitted. For example, on
7708-463: The same commands from other command lines (such as the BBC BASIC command line), by preceding the command with a * . A command-line argument or parameter is an item of information provided to a program when it is started. A program can have many command-line arguments that identify sources or destinations of information, or that alter the operation of the program. When a command processor
7802-486: The use of "Number Cards", "pierced with certain holes and stand[ing] opposite levers connected with a set of figure wheels ... advanced they push in those levers opposite to which there are no holes on the cards and thus transfer that number together with its sign" in his description of the Calculating Engine's Store. There is no evidence that he built a practical example. In 1881, Jules Carpentier developed
7896-455: The user terminated by the Enter key , then execute the specified command and provide textual display of results or error messages. Advanced CLIs will validate, interpret and parameter-expand the command line before executing the specified command, and optionally capture or redirect its output. Unlike a button or menu item in a GUI, a command line is typically self-documenting, stating exactly what
7990-410: The user wants done. In addition, command lines usually include many defaults that can be changed to customize the results. Useful command lines 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
8084-615: The user-interface, including fully graphically oriented ones. For example, the default Windows GUI is a shell program named EXPLORER.EXE , as defined in the SHELL=EXPLORER.EXE line in the WIN.INI configuration file. These programs are shells, but not CLIs. Application programs (as opposed to operating systems) may also have command-line interfaces. An application program may support none, any, or all of these three major types of command-line interface mechanisms: Some applications support
8178-438: Was awarded three patents in 1889 for electromechanical tabulating machines . These patents described both paper tape and rectangular cards as possible recording media. The card shown in U.S. patent 395,781 of January 8 was printed with a template and had hole positions arranged close to the edges so they could be reached by a railroad conductor 's ticket punch , with the center reserved for written descriptions. Hollerith
8272-537: Was comparable to the IBM Stub card. Mark sense ( electrographic ) cards, developed by Reynold B. Johnson at IBM, have printed ovals that could be marked with a special electrographic pencil. Cards would typically be punched with some initial information, such as the name and location of an inventory item. Information to be added, such as quantity of the item on hand, would be marked in the ovals. Card punches with an option to detect mark sense cards could then punch
8366-450: Was developed independently on several occasions in the modern period. In most cases there is no evidence that each of the inventors was aware of the earlier work. Basile Bouchon developed the control of a loom by punched holes in paper tape in 1725. The design was improved by his assistant Jean-Baptiste Falcon and by Jacques Vaucanson . Although these improvements controlled the patterns woven, they still required an assistant to operate
8460-507: Was originally inspired by railroad tickets that let the conductor encode a rough description of the passenger: I was traveling in the West and I had a ticket with what I think was called a punch photograph...the conductor...punched out a description of the individual, as light hair, dark eyes, large nose, etc. So you see, I only made a punch photograph of each person. When use of the ticket punch proved tiring and error-prone, Hollerith developed
8554-568: Was part of the Multics time-sharing operating system . In 1964, MIT Computation Center staff member Louis Pouzin developed the RUNCOM tool for executing command scripts while allowing argument substitution. Pouzin coined the term shell to describe the technique of using commands like a programming language, and wrote a paper about how to implement the idea in the Multics operating system. Pouzin returned to his native France in 1965, and
8648-515: Was quickly superseded by the 1973 IBM 3740 Data Entry System using 8-inch floppy disks . The Powers/Remington Rand card format was initially the same as Hollerith's; 45 columns and round holes. In 1930, Remington Rand leap-frogged IBM's 80 column format from 1928 by coding two characters in each of the 45 columns – producing what is now commonly called the 90-column card. There are two sets of six rows across each card. The rows in each set are labeled 0, 1/2, 3/4, 5/6, 7/8 and 9. The even numbers in
8742-516: Was to use columns 1 through 72 for data, and columns 73 through 80 to sequentially number the cards, as shown in the picture above of a punched card for FORTRAN. Such numbered cards could be sorted by machine so that if a deck was dropped the sorting machine could be used to arrange it back in order. This convention continued to be used in FORTRAN, even in later systems where the data in all 80 columns could be read. The IBM card readers 3504, 3505 and
8836-670: Was used by the Allies in some of their efforts to decrypt Axis communications. See, for example, Central Bureau in Australia. At Bletchley Park in England, "some 2 million punched cards a week were being produced, indicating the sheer scale of this part of the operation". In Nazi Germany, punched cards were used for the censuses of various regions and other purposes (see IBM and the Holocaust ). Punched card technology developed into
#267732