document_title: Command-line interface

question_text: list three example of software that used command line interface in real life application

question_tokens: list three example of software that used command line interface in real life application

text: Command-line interface

text: Comparison to graphical user interfaces[edit]

text: Compared with a graphical user interface,a command line requires fewer system resources to implement. Since options to commands are given in a few characters in each command line, an experienced user finds the options easier to access. Automation of repetitive tasks is simplified - most operating systems using a command line interface support some mechanism for storing frequently used sequences in a disk file, for re-use; 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.

text: A command-line system may require paper or on-line manuals for the user's reference, although often a "help" option provides a concise review of the options of a command. The command line environment may not provide the 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 drop-down menus of a graphical user interface, without repeated reference to manuals.

text: Operating system command-line interfaces[edit]

text: Operating system (OS) command line interfaces are usually distinct programs supplied with the operating system. A program that implements such a text interface is often called a command-line interpreter, command processor or shell.

text: Examples of command-line interpreters include DEC's DIGITAL Command Language (DCL) in OpenVMS and RSX-11, the various Unix shells (sh, ksh, csh, tcsh, bash, etc.), the historical CP/M CCP, and MS-DOS/IBM-DOS/DR-DOS's COMMAND.COM, as well as the OS/2 and 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 or Take Command for Windows.

text: Although the term 'shell' is often used to describe a command-line interpreter, strictly speaking a 'shell' can be any program that constitutes 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.

text: Application command-line interfaces[edit]

text: Application programs (as opposed to operating systems) may also have command line interfaces.

text: An application program may support none, any, or all of these three major types of command line interface mechanisms:

text:
Parameters: Most operating systems support a means to pass additional information to a program when it is launched. When a program is launched from an OS command line shell, additional text provided along with the program name is passed to the launched program.
Interactive command line sessions: After launch, a program may provide an operator with an independent means to enter commands in the form of text.
OS inter-process communication: Most operating systems support means of inter-process communication (for example; standard streams or named pipes). Command lines from client processes may be redirected to a CLI program by one of these methods.

text: Some applications support only a CLI, presenting a CLI prompt to the user and acting upon command lines as they are entered. 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 the CLI, whereas the MATLAB GUI exposes only a subset of features.

text: The early Sierra games, like the first three King's Quest games (1984–1986), used commands from an internal command line to move the character around in the graphic window.

text: History[edit]

text: The command-line interface evolved from a form of dialog once conducted by humans over teleprinter (TTY) machines, in which human operators remotely exchanged information, usually one line of text at a time. Early computer systems often used teleprinter machines as the means of interaction with a human operator. The computer became one end of the human-to-human teleprinter model. So instead of a human communicating with another human over a teleprinter, a human communicated with a computer.

text: 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 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.

text: 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 was part of the Multics time-sharing operating system.[2]In 1964, MIT Computation Center staff member Louis Pouzin developed the RUNCOM tool for executing command scripts while allowing argument substitution.[3] 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.[4] Pouzin returned to his native France in 1965, and the first Multics shell was developed by Glenda Schroeder.[3]

text: 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.[5][6] 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 the features that are commonly considered to produce structured programs. The Bourne shell led to the development of the Korn shell (ksh), Almquist shell (ash), and the popular Bourne-again shell (or Bash).[6]

text: Early microcomputers themselves were based on a command-line interface such as CP/M, MS-DOS or AppleSoft BASIC. Throughout the 1980s and 1990s—especially after the introduction of the Apple Macintosh and Microsoft Windows—command line interfaces were replaced in popular usage by the Graphical User Interface. The command line remains in use, however, by system administrators and other advanced users for system administration, computer programming, and batch processing.

text: 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 a Unix-like CLI. Microsoft provides MKS Inc.'s ksh implementation MKS Korn shell for Windows through their Services for UNIX add-on.

text: Since 2001, the Macintosh operating system is based on a variation of Unix called Darwin. On these computers, users can access a Unix-like command-line interface called Terminal found in the Applications Utilities folder. This terminal uses bash by default.

text: Usage[edit]

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tag: table

text: 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 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.

text: 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 disability, since the commands and responses can be displayed using Refreshable Braille displays.

text: Anatomy of a shell CLI[edit]

text: This section needs additional citations for verification. Please help improve this article by adding citations to reliable sources. Unsourced material may be challenged and removed. (July 2015) (Learn how and when to remove this template message)

text: The general pattern of an OS command line interface[7][8] is:

text: Prompt command param1 param2 param3 ... paramN

text:
Prompt - generated by the program to provide context for the client.
Command — provided by the client. Commands are usually one of three classes:

Internal — recognized and processed by the command line interpreter itself and not dependent upon any external executable file.
Included — A separate executable file generally considered part of the operating environment and always included with the OS.
External — External executable files not part of the basic OS, but added by other parties for specific purposes and applications.

param1 ...paramN — Optional parameters provided by the client. The format and meaning of the parameters depends upon the command issued. In the case of Included or External commands, the values of the parameters are delivered to the program (specified by the Command) as it is launched by the OS. Parameters may be either Arguments or Options.

text: In this example, 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 for command-line interfaces.

text: A CLI can generally be considered as consisting of syntax and semantics. The syntax is the grammar that all commands must follow. In the case of operating systems (OS), MS-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 that all commands within their CLI conform to. 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 the grammar represents these operations and data—the symbolic meaning in the syntax.

text: 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.

text: A simple CLI will display a prompt, accept a "command line" typed by 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.

text: Unlike a button or menu item in a GUI, a command line is typically self-documenting, stating exactly what 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 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.

text: The commands given to a CLI shell are often in one of the following forms:

text:
doSomething how toFiles
doSomething how sourceFile destinationFile
doSomething how < inputFile > outputFile
doSomething how | doSomething how | doSomething how > outputFile

text: 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 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 a pipeline where the output of one command becomes the input to the next command.

text: CLI and resource protection[edit]

text: 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 the default is the opposite. Renaming of the executables also works: people often rename their favourite editor to EDIT, for example.

text: 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 the prompt.

text: 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 the interface mode. At this point, commands from the system mode may not be accessible and the user exits the interface mode and enters the system mode.

text: Command prompt[edit]

text: 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 $, %, #, :, > and often includes other information, such as the path of the current working directory and the hostname.

text: 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).

text: End-users can often modify prompts. Depending on the environment, they may include colors, special characters, and other elements (like variables and functions for 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 the prompt.

text: In DOS's 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 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.

text: Many Unix systems feature the $PS1 variable (Prompt String 1),[9] although other variables also may affect the prompt (depending on the shell used). In the bash shell, a prompt of the form:

text: could be set by issuing the command

text: 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.

text: In RISC OS the command prompt is a * symbol, and thus (OS)CLI commands are often referred to as "star commands".[10] One can also access the same commands from other command lines (such as the BBC BASIC command line), by preceding the command with a *.

text: Arguments[edit]

text: 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.

text: When a command processor 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:

text: "file.s" is a command-line argument which tells the program rm to remove the file "file.s".

text: 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 the main function. Other languages, such as Python, expose these arguments as global variables.

text: In Unix-like operating systems, a single hyphen-minus by itself is usually a special value specifying that a program should handle data coming from the standard input or send data to the standard output.

text: Command-line option[edit]

text: A command-line option or simply option (also known as 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, for example Dir/? and DIR /? have the same effect in DOS (list the DIR command's options) whereas dir --help (in many versions of Unix) does require the option to be preceded by at least one space (and is case-sensitive).

text: 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.

text: A few representative samples of command-line options, all relating to listing files in a directory, to illustrate some conventions:

text:
Operating system
Command
Valid alternative
Notes

OpenVMS
directory/owner
Dir /Owner
instruct the directory command to also display the ownership of the files.
Note the Directory command name is not case sensitive, and can be abbreviated to as few letters as required to remain unique.

DOS
dir/Q/O:S d*
diR /q d* /o:s
display ownership of files whose names begin with "D", sorted by size, smallest first.
Note spaces around argument d* are required.

Unix-like systems
ls -lS D*
ls -S -l D*
display in long format files and directories beginning with "D" (but not "d"), sorted by size (largest first).
Note spaces are required around all arguments and options, but some can be run together, e.g. -lS is the same as -l -S.

Data General RDOS CLI
list/e/s 04-26-80/b
List /S/E 4-26-80/B
list every attribute for files created before 26 April 1980.
Note the /B at the end of the date argument is a local switch, that modifies the meaning of that argument, while /S and /E are global switches, i.e. apply to the whole command.

text: Abbreviating commands[edit]

text: In Multics, command-line options and subsystem keywords may be abbreviated. This idea appears to derive from the PL/I programming language, with its shortened keywords (e.g., STRG for STRINGRANGE and DCL for DECLARE). For example, in the Multics "forum" subsystem, the -long_subject parameter can be abbreviated -lgsj. It is also common for Multics commands to be abbreviated, typically corresponding to the initial letters of the words that are strung together with underscores to form command names, such as the use of did for delete_iacl_dir.

text: In some other systems abbreviations are automatic, such as permitting enough of the first characters of a command name to uniquely identify it (such as SU as an abbreviation for SUPERUSER) while others may have some specific abbreviations pre-programmed (e.g. MD for MKDIR in COMMAND.COM) or user-defined via batch scripts and aliases (e.g. alias md mkdir in tcsh). See also: Tab completion.

text: Option conventions in DOS, Windows, OS/2[edit]

text: On DOS, OS/2 and Windows, different programs called from their COMMAND.COM or CMD.EXE (or internal their commands) may use different syntax within the same operating system. For example:

text:
Options may be indicated by either of the "switch characters": -, /, or either may be allowed. See below.
They may or may not be case-sensitive.
Sometimes options and their arguments are run together, sometimes separated by whitespace, and sometimes by a character, typically : or =; thus Prog -fFilename, Prog -f Filename, Prog -f:Filename, Prog -f=Filename.
Some programs allow single-character options to be combined; others do not. The switch -fA may mean the same as -f -A, or it may be incorrect, or it may even be a valid but different parameter.

text: In DOS, OS/2 and Windows, the forward slash (/) is most prevalent, although the hyphen-minus is also sometimes used. In many versions of DOS (MS-DOS/PC DOS 2.xx and higher, all versions of DR-DOS since 5.0, as well as PTS-DOS, Embedded DOS, FreeDOS and RxDOS) the switch character (sometimes abbreviated switchar or switchchar) to be used is defined by a value returned from a system call (INT 21h/AH=37h). The default character returned by this API is /, but can be changed to a hyphen-minus on the above-mentioned systems, except for Datalight ROM-DOS and MS-DOS/PC DOS 5.0 and higher, which always return / from this call (unless one of many available TSRs to reenable the SwitChar feature is loaded). In some of these systems (MS-DOS/PC DOS 2.xx, DOS Plus 2.1, DR-DOS 7.02 and higher, PTS-DOS, Embedded DOS, FreeDOS and RxDOS), the setting can also be pre-configured by a SWITCHAR directive in CONFIG.SYS. Embedded DOS provides a SWITCH command for the same purpose, whereas 4DOS allows the setting to be changed via SETDOS /W:n. Under DR-DOS, if the setting has been changed from /, the first directory separator \ in the display of the PROMPT parameter $G will change to a forward slash / (which is also a valid directory separator in DOS, FlexOS, 4680 OS, 4690 OS, OS/2 and Windows) thereby serving as a visual clue to indicate the change. Some versions of DR-DOS COMMAND.COM also support a PROMPT token $/ to display the current setting. COMMAND.COM since DR-DOS 7.02 and 4DOS also provide a pseudo-environment variable named %/% to allow portable batchjobs to be written. Several external DR-DOS commands additionally support an environment variable %SWITCHAR% to override the system setting.

text: However, many programs are hardwired to use / only, rather than retrieving the switch setting before parsing command line arguments. A very small number, mainly ports from Unix-like systems, are programmed to accept "-" even if the switch character is not set to it (for example netstat and ping, supplied with Windows, will accept the /? option to list available options, and yet the list will specify the "-" convention).

text: Option conventions in Unix-like systems[edit]

text: In Unix-like systems, the ASCII hyphen-minus begins options; the new (and GNU) convention is to use two hyphens then a word (e.g. --create) to identify the option's use while the old convention (and still available as an option for frequently-used options) is to use one hyphen then one letter (e.g. -c); if one hyphen is followed by two or more letters it may mean two options are being specified, or it may mean the second and subsequent letters are a parameter (such as filename or date) for the first option.

text: Two hyphen-minus characters without following letters (--) may indicate that the remaining arguments should not be treated as options, which is useful for example if a file name itself begins with a hyphen, or if further arguments are meant for an inner command (e.g. sudo). Double hyphen-minuses are also sometimes used to prefix "long options" where more descriptive option names are used. This is a common feature of GNU software. The getopt function and program, and the getopts command are usually used for parsing command-line options.

text: Unix command names, arguments and options are case-sensitive (except in a few examples, mainly where popular commands from other operating systems have been ported to Unix).

text: Options conventions in other systems[edit]

text: FlexOS, 4680 OS and 4690 OS use -.

text: CP/M typically used [.

text: Conversational Monitor System (CMS) uses a single left parenthesis to separate options at the end of the command from the other arguments. For example, in the following command the options indicate that the target file should be replaced if it exists, and the date and time of the source file should be retained on the copy: COPY source file a target file b (REPLACE OLDDATE

text: Data General's CLI under their RDOS, AOS, etc. operating systems, as well as the version of CLI that came with their Business Basic, uses only / as the switch character, is case-insensitive, and allows "local switches" on some arguments to control the way they are interpreted, such as MAC/U LIB/S A B C $LPT/L has the global option "U" to the macro assembler command to appemd user symbols, but two local switches, one to specify LIB should be skipped on pass 2 and the other to direct listing to the printer, $LPT.

text: Built-in usage help[edit]

text: One of the criticisms of a CLI is the lack of cues to the user as to the available actions.[citation needed] In contrast, GUIs usually inform the user of available actions with menus, icons, or other visual cues.[citation needed] To overcome this limitation, many CLI programs display a brief summary of its valid parameters, typically when invoked with no arguments or one of ?, -?, -h, -H, /?, /h, /H, -help, or --help.[citation needed]

text: However, entering a program name without parameters in the hope that it will display usage help can be hazardous, as some programs and scripts execute without further notice.[citation needed]

text: Although desirable at least for the help parameter, programs may not support all option lead-in characters exemplified above. Under DOS, where the default command line option character can be changed from / to -, programs may query the SwitChar API in order to determine the current setting. So, if a program is not hard-wired to support them all, a user may need to know the current setting even to be able to reliably request help. If the SwitChar has been changed to - and therefore the / character is accepted as alternative path delimiter also at the DOS command line, programs may misinterpret options like /h or /H as paths rather than help parameters. However, if given as first or only parameter, most DOS programs will, by convention, accept it as request for help regardless of the current SwitChar setting.

text: In some cases, different levels of help can be selected for a program. Some programs supporting this allow to give a verbosity level as an optional argument to the help parameter (as in /H:1, /H:2, etc.) or they give just a short help on help parameters with question mark and a longer help screen for the other help options.

text: Depending on the program, additional or more specific help on accepted parameters is sometimes available by either providing the parameter in question as an argument to the help parameter or vice versa (as in /H:W or in /W:? (assuming /W would be another parameter supported by the program)).

text: In a similar fashion to the help parameter, but much less common, some programs provide additional information about themselves (like mode, status, version, author, license or contact information) when invoked with an "about" parameter like -!, /!, -about, or --about.

text: Since the ? and ! characters typically also serve other purposes at the command line, they may not be available in all scenarios, therefore, they should not be the only options to access the corresponding help information.

text: If more detailed help is necessary than provided by a program's built-in internal help, many systems support a dedicated external "HELP command" command (or similar), which accepts a command name as calling parameter and will invoke an external help system.

text: In the DR-DOS family, typing /? or /H at the COMMAND.COM prompt instead of a command itself will display a dynamically generated list of available internal commands; 4DOS and NDOS support the same feature by typing ? at the prompt (which is also accepted by newer versions of DR-DOS COMMAND.COM); internal commands can be individually disabled or reenabled via SETDOS /I. In addition to this, some newer versions of DR-DOS COMMAND.COM also accept a ?% command to display a list of available built-in pseudo-environment variables. Besides their purpose as quick help reference this can be used in batchjobs to query the facilities of the underlying command line processor.

text: Command description syntax[edit]

text: Built-in usage help and man pages commonly employ a small syntax to describe the valid command form:[11][12]

text:
angle brackets for required parameters: ping <hostname>
square brackets for optional parameters: mkdir [-p] <dirname>
ellipses for repeated items: cp <source1> [source2...] <dest>
vertical bars for choice of items: netstat {-t|-u}

text: Notice that these characters have different meanings than when used directly in the shell. Angle brackets may be omitted when confusing the parameter name with a literal string is not likely.

text: The space character[edit]

text: In many areas of computing, but particularly in the command line, the space character can cause problems as it has two distinct and incompatible functions: as part of a command or parameter, or as a parameter or name separator. Ambiguity can be prevented either by prohibiting embedded spaces in file and directory names in the first place (for example, by substituting them with underscores _), or by enclosing a name with embedded spaces between quote characters or using an escape character before the space, usually a backslash (\). For example

text: is ambiguous (is "program name" part of the program name, or two parameters?); however

text: and

text: are not ambiguous. Unix-based operating systems minimize the use of embedded spaces to minimize the need for quotes. In Microsoft Windows, one often has to use quotes because embedded spaces (such as in directory names) are common.

text: Command-line interpreter[edit]

text: Although most users think of the shell as an interactive command interpreter, it is really a programming language in which each statement runs a command. Because it must satisfy both the interactive and programming aspects of command execution, it is a strange language, shaped as much by history as by design.

text: The terms command-line interpreter, command line shell, command language interpreter, or identical abbreviation CLI, are applied to computer programs designed to interpret a sequence of lines of text which may be entered by a user, read from a file or another kind of data stream. The context of interpretation is usually one of a given operating system or programming language.

text: Command-line interpreters allow users to issue various commands in a very efficient (and often terse) way. This requires the user to know the names of the commands and their parameters, and the syntax of the language that is interpreted.

text: The Unix #! mechanism and OS/2 EXTPROC command facilitate the passing of batch files to external processors. One can use these mechanisms to write specific command processors for dedicated uses, and process external data files which reside in batch files.

text: Many graphical interfaces, such as the OS/2 Presentation Manager and early versions of Microsoft Windows use command-lines to call helper programs to open documents and programs. The commands are stored in the graphical shell[clarification needed] or in files like the registry or the OS/2 os2user.ini file.

text: Early history[edit]

text: The earliest computers did not support interactive input/output devices, often relying on sense switches and lights to communicate with the computer operator. This was adequate for batch systems that ran one program at a time, often with the programmer acting as operator. This also had the advantage of low overhead, since lights and switches could be tested and set with one machine instruction. Later a single system console was added to allow the operator to communicate with the system.

text: From the 1960s onwards, user interaction with computers was primarily by means of command-line interfaces, initially on machines like the Teletype Model 33 ASR, but then on early CRT-based computer terminals such as the VT52.

text: All of these devices were purely text based, with no ability to display graphic or pictures.[14] For business application programs, text-based menus were used, but for more general interaction the command line was the interface.

text: Around 1964 Louis Pouzin introduced the concept and the name shell in Multics, building on earlier, simpler facilities in the Compatible Time-Sharing System (CTSS).[15][better source needed]

text: From the early 1970s the Unix operating system adapted the concept of a powerful command-line environment, and introduced the ability to pipe the output of one command in as input to another. Unix also had the capability to save and re-run strings of commands as "shell scripts" which acted like custom commands.

text: The command-line was also the main interface for the early home computers such as the Commodore PET, Apple II and BBC Micro – almost always in the form of a BASIC interpreter. When more powerful business oriented microcomputers arrived with CP/M and later MS-DOS computers such as the IBM PC, the command-line began to borrow some of the syntax and features of the Unix shells such as globbing and piping of output.

text: The command-line was first seriously challenged by the PARC GUI approach used in the 1983 Apple Lisa and the 1984 Apple Macintosh. A few computer users used GUIs such as GEOS and Windows 3.1 but the majority of IBM PC users did not replace their command.com shell with a GUI until Windows 95 was released in 1995.[16][17]

text: Modern usage as an operating system shell[edit]

text: While most non-expert computer users now use a GUI almost exclusively, more advanced users have access to powerful command-line environments:

text:
The default VAX/VMS command shell, using the DCL language, has been ported to Windows systems at least three times, including PC-DCL and Acceler8 DCL Lite. MS-DOS 6.22 has been ported to Linux type systems, Unix command shells have been ported to VMS and MS-DOS/Windows 95 and Windows NT types of operating systems. Command.com and Windows NT cmd.exe have been ported to Windows CE and presumably works on Microsoft Windows NT Embedded 4.0
Windows Resource Kit and Windows Services for Unix include Korn and the Bourne shells along with a Perl interpreter (Services of Unix contains Active State ActivePerl in later versions and Interix for versions 1 and 2 and a shell compiled by Microsoft)
IBM OS/2 has the cmd.exe processor. This copies the command.com commands, with extensions to REXX.
Cmd.exe and Command.com are part of the Windows NT stream operating systems.
Yet another Cmd.exe is a stripped-down shell for Windows CE 3.0
An MS-DOS type interpreter called PocketDOS has been ported to Windows CE machines; the most recent release is almost identical to MS-DOS 6.22 and can also run Windows 1, 2, and 3.0, QBasic and other development tools, 4NT and 4DOS. The latest release includes several shells, namely MS-DOS 6.22, PC-DOS 7, DR DOS 3, and others
PocketConsole is a Windows NT 4.0 shell for Windows CE that is much like 4NT
Windows users have a CLI environment named Windows Command Prompt, which might use the CScript interface to alternate programs. PowerShell provides a command-line interface, but its applets are not written in Shell script. Implementations of the Unix shell are also available as part of the POSIX sub-system,[18] Cygwin, MKS Toolkit, UWIN, Hamilton C shell and other software packages. Available shells for these interoperability tools include csh, ksh, sh, bash, rsh, tclsh and less commonly zsh, ysh, psh
Command.com (4DOS), Windows NT cmd.exe (4NT, TCC), and OS/2 cmd.exe (4OS2) and others based on them are enhanced shells which can be a replacement for the native shell or a means of enhancement of the default shell
Implementations of PHP have a shell for interactive use called php-cli.
Standard Tcl/Tk has two interactive shells, Tclsh and Wish, the latter being the GUI version.
Python, Ruby, Lua, XLNT, and other interpreters also have command shells for interactive use.
FreeBSD uses tcsh as its default interactive shell for the superuser.
Apple macOS[19] and many Linux distributions have the Bash implementation of the Unix shell. Early versions of macOS used tcsh as the default shell.
Embedded Linux (and other embedded Unix-like) devices often use the Ash implementation of the Unix shell, as part of Busybox.
Android uses the mksh shell,[20][21] which replaces a shell derived from ash[22] that was used in older Android versions, supplemented with commands from the separate toolbox[23] binary.
Routers with Cisco IOS,[24] Junos[25] and many others are commonly configured from the command line.

text: Scripting[edit]

text: Most command-line interpreters support scripting, to various extents. (They are, after all, interpreters of an interpreted programming language, albeit in many cases the language is unique to the particular command-line interpreter.) They will interpret scripts (variously termed shell scripts or batch files) written in the language that they interpret. Some command-line interpreters also incorporate the interpreter engines of other languages, such as REXX, in addition to their own, allowing the executing of scripts, in those languages, directly within the command-line interpreter itself.

text: Conversely, scripting programming languages, in particular those with an eval function (such as REXX, Perl, Python, Ruby or Jython), can be used to implement command-line interpreters and filters. For a few operating systems, most notably DOS, such a command interpreter provides a more flexible command line interface than the one supplied. In other cases, such a command interpreter can present a highly customised user interface employing the user interface and input/output facilities of the language.

text: Other command-line interfaces[edit]

text: The command line provides an interface between programs as well as the user. In this sense, a command line is an alternative to a dialog box. Editors and data-bases present a command line, in which alternate command processors might run. On the other hand, one might have options on the command line which opens a dialog box. The latest version of 'Take Command' has this feature. DBase used a dialog box to construct command lines, which could be further edited before use.

text: Programs like Basic, Diskpart, Edlin, and QBasic all provide command-line interfaces, some of which use the system shell. Basic is modeled on the default interface for 8-bit Intel computers. Calculators can be run as command-line or dialog interfaces.

text: Emacs provides a command line interface in the form of its minibuffer. Commands and arguments can be entered using Emacs standard text editing support, and output is displayed in another buffer.

text: There are a number of pre-mouse games, like Adventure or King's Quest 1-3, which relied on the user typing commands at the bottom of the screen. One controls the character by typing commands like 'get ring' or 'look'. The program returns a text which describes how the character sees it, or makes the action happen. The text adventure The Hitchhiker's Guide to the Galaxy, a piece of interactive fiction based on Douglas Adam's book of the same name, is a teletype-style command-line game.

text: The most notable of these interfaces is the standard streams interface, which allows the output of one command to be passed to the input of another. Text files can serve either purpose as well. This provides the interfaces of piping, filters and redirection. Under Unix, devices are files too, so the normal type of file for the shell used for stdin,stdout and stderr is a tty device file.

text: Another command-line interface allows a shell program to launch helper programs, either to launch documents or start a program. The command is processed internally by the shell, and then passed on to another program to launch the document. The graphical interface of Windows and OS/2 rely heavily on command-lines passed through to other programs – console or graphical, which then usually process the command line without presenting a user-console.

text: Programs like the OS/2 E editor and some other IBM editors, can process command-lines normally meant for the shell, the output being placed directly in the document window.

text: A web browser's URL input field can be used as a command line. It can be used to "launch" web apps, access browser configuration, as well as perform a search. Google, which has been called "the command line of the internet" will perform a domain-specific search when it detects search parameters in a known format.[26] This functionality is present whether the search is triggered from a browser field or one on Google's web site.


document_title: Great Pyramid of Giza

question_text: what was the great pyramid of giza made out of

root

text: Great Pyramid of Giza

text: History and description

text: Egyptologists believe the pyramid was built as a tomb for the Fourth Dynasty Egyptian pharaoh Khufu (often Hellenized as "Cheops") and was constructed over a 20-year period. Khufu's vizier, Hemiunu (also called Hemon) is believed by some to be the architect of the Great Pyramid.[2] It is thought that, at construction, the Great Pyramid was originally 280 Egyptian Royal cubits tall (146.5 metres (480.6 ft)), but with erosion and absence of its pyramidion, its present height is 138.8 metres (455.4 ft). Each base side was 440 cubits, 230.4 metres (755.9 ft) long. The mass of the pyramid is estimated at 5.9 million tonnes. The volume, including an internal hillock, is roughly 2,500,000 cubic metres (88,000,000 cu ft).[3]

tag: p

text: Based on these estimates, building the pyramid in 20 years would involve installing approximately 800 tonnes of stone every day. Additionally, since it consists of an estimated 2.3 million blocks, completing the building in 20 years would involve moving an average of more than 12 of the blocks into place each hour, day and night. The first precision measurements of the pyramid were made by Egyptologist Sir Flinders Petrie in 1880–82 and published as The Pyramids and Temples of Gizeh.[4] Almost all reports are based on his measurements. Many of the casing-stones and inner chamber blocks of the Great Pyramid fit together with extremely high precision. Based on measurements taken on the north-eastern casing stones, the mean opening of the joints is only 0.5 millimetre wide (1/50 of an inch).[5]

text: The pyramid remained the tallest man-made structure in the world for over 3,800 years,[6] unsurpassed until the 160-metre-tall (520 ft) spire of Lincoln Cathedral was completed c. 1300. The accuracy of the pyramid's workmanship is such that the four sides of the base have an average error of only 58 millimetres in length.[7] The base is horizontal and flat to within ±15 mm (0.6 in).[8] The sides of the square base are closely aligned to the four cardinal compass points (within four minutes of arc)[9] based on true north, not magnetic north,[10] and the finished base was squared to a mean corner error of only 12 seconds of arc.[11]

text: The completed design dimensions, as suggested by Petrie's survey and subsequent studies, are estimated to have originally been 280 Egyptian Royal cubits high by 440 cubits long at each of the four sides of its base. The ratio of the perimeter to height of 1760/280 Egyptian Royal cubits equates to 2π to an accuracy of better than 0.05% (corresponding to the well-known approximation of π as 22/7). Some Egyptologists consider this to have been the result of deliberate design proportion. Verner wrote, "We can conclude that although the ancient Egyptians could not precisely define the value of π, in practice they used it".[12] Petrie, author of Pyramids and Temples of Gizeh concluded: "but these relations of areas and of circular ratio are so systematic that we should grant that they were in the builder's design".[13] Others have argued that the Ancient Egyptians had no concept of pi and would not have thought to encode it in their monuments. They believe that the observed pyramid slope may be based on a simple seked slope choice alone, with no regard to the overall size and proportions of the finished building.[14] In 2013, rolls of papyrus called the Diary of Merer were discovered written by some of those who delivered limestone and other construction materials from Tora to Giza.[15]

text: Materials

text: The Great Pyramid consists of an estimated 2.3 million blocks which most believe to have been transported from nearby quarries. The Tura limestone used for the casing was quarried across the river. The largest granite stones in the pyramid, found in the "King's" chamber, weigh 25 to 80 tonnes and were transported from Aswan, more than 800 km (500 mi) away. Traditionally,[clarification needed] ancient Egyptians cut stone blocks by hammering into them wooden wedges, which were then soaked with water. As the water was absorbed, the wedges expanded, causing the rock to crack. Once they were cut, they were carried by boat either up or down the Nile River to the pyramid.[16] It is estimated that 5.5 million tonnes of limestone, 8,000 tonnes of granite (imported from Aswan), and 500,000 tonnes of mortar were used in the construction of the Great Pyramid.[17]

text: Casing stones

text: At completion, the Great Pyramid was surfaced by white "casing stones" – slant-faced, but flat-topped, blocks of highly polished white limestone. These were carefully cut to what is approximately a face slope with a seked of 5½ palms to give the required dimensions. Visibly, all that remains is the underlying stepped core structure seen today. In AD 1303, a massive earthquake loosened many of the outer casing stones, which were then carted away by Bahri Sultan An-Nasir Nasir-ad-Din al-Hasan in 1356 to build mosques and fortresses in nearby Cairo. Many more casing stones were removed from the great pyramids by Muhammad Ali Pasha in the early 19th century to build the upper portion of his Alabaster Mosque in Cairo, not far from Giza. These limestone casings can still be seen as parts of these structures. Later explorers reported massive piles of rubble at the base of the pyramids left over from the continuing collapse of the casing stones, which were subsequently cleared away during continuing excavations of the site.

text: Nevertheless, a few of the casing stones from the lowest course can be seen to this day in situ around the base of the Great Pyramid, and display the same workmanship and precision that has been reported for centuries. Petrie also found a different orientation in the core and in the casing measuring 193 centimetres ± 25 centimetres. He suggested a redetermination of north was made after the construction of the core, but a mistake was made, and the casing was built with a different orientation.[4] Petrie related the precision of the casing stones as to being "equal to opticians' work of the present day, but on a scale of acres" and "to place such stones in exact contact would be careful work; but to do so with cement in the joints seems almost impossible".[19] It has been suggested it was the mortar (Petrie's "cement") that made this seemingly impossible task possible, providing a level bed, which enabled the masons to set the stones exactly.[20][21]

text: Construction theories

text: Many alternative, often contradictory, theories have been proposed regarding the pyramid's construction techniques.[22] Many disagree on whether the blocks were dragged, lifted, or even rolled into place. The Greeks believed that slave labour was used, but modern discoveries made at nearby workers' camps associated with construction at Giza suggest that it was built instead by tens of thousands of skilled workers. Verner posited that the labour was organized into a hierarchy, consisting of two gangs of 100,000 men, divided into five zaa or phyle of 20,000 men each, which may have been further divided according to the skills of the workers.[23]

text: One mystery of the pyramid's construction is its planning. John Romer suggests that they used the same method that had been used for earlier and later constructions, laying out parts of the plan on the ground at a 1-to-1 scale. He writes that "such a working diagram would also serve to generate the architecture of the pyramid with precision unmatched by any other means".[24] He also argues for a 14-year time-span for its construction.[25] A modern construction management study, in association with Mark Lehner and other Egyptologists, estimated that the total project required an average workforce of about 14,500 people and a peak workforce of roughly 40,000. Without the use of pulleys, wheels, or iron tools, they used critical path analysis methods, which suggest that the Great Pyramid was completed from start to finish in approximately 10 years.[26]

text: Interior

text: The original entrance to the Great Pyramid is on the north, 17 metres (56 ft) vertically above ground level and 7.29 metres (23.9 ft) east of the centre line of the pyramid. From this original entrance, there is a Descending Passage 0.96 metres (3.1 ft) high and 1.04 metres (3.4 ft) wide, which goes down at an angle of 26° 31'23" through the masonry of the pyramid and then into the bedrock beneath it. After 105.23 metres (345.2 ft), the passage becomes level and continues for an additional 8.84 metres (29.0 ft) to the lower Chamber, which appears not to have been finished. There is a continuation of the horizontal passage in the south wall of the lower chamber; there is also a pit dug in the floor of the chamber. Some Egyptologists suggest that this Lower Chamber was intended to be the original burial chamber, but Pharaoh Khufu later changed his mind and wanted it to be higher up in the pyramid.[27]

text: 28.2 metres (93 ft) from the entrance is a square hole in the roof of the Descending Passage. Originally concealed with a slab of stone, this is the beginning of the Ascending Passage. The Ascending Passage is 39.3 metres (129 ft) long, as wide and high as the Descending Passage and slopes up at almost precisely the same angle to reach the Grand Gallery. The lower end of the Ascending Passage is closed by three huge blocks of granite, each about 1.5 metres (4.9 ft) long. One must use the Robbers' Tunnel (see below) to access the Ascending Passage. At the start of the Grand Gallery on the right-hand side there is a hole cut in the wall. This is the start of a vertical shaft which follows an irregular path through the masonry of the pyramid to join the Descending Passage. Also at the start of the Grand Gallery there is the Horizontal Passage leading to the "Queen's Chamber". The passage is 1.1m (3'8") high for most of its length, but near the chamber there is a step in the floor, after which the passage is 1.73 metres (5.7 ft) high.

text: Queen's Chamber

text: The "Queen's Chamber"[1] is exactly halfway between the north and south faces of the pyramid and measures 5.75 metres (18.9 ft) north to south, 5.23 metres (17.2 ft) east to west, and has a pointed roof with an apex 6.23 metres (20.4 ft) above the floor. At the eastern end of the chamber there is a niche 4.67 metres (15.3 ft) high. The original depth of the niche was 1.04 metres (3.4 ft), but has since been deepened by treasure hunters.[28]

text: In the north and south walls of the Queen's Chamber there are shafts, which, unlike those in the King's Chamber that immediately slope upwards (see below), are horizontal for around 2 m (6.6 ft) before sloping upwards. The horizontal distance was cut in 1872 by a British engineer, Waynman Dixon, who believed a shaft similar to those in the King's Chamber must also exist. He was proved right, but because the shafts are not connected to the outer faces of the pyramid or the Queen's Chamber, their purpose is unknown. At the end of one of his shafts, Dixon discovered a ball of black diorite (a type of rock) and a bronze implement of unknown purpose. Both objects are currently in the British Museum.[29]

text: The shafts in the Queen's Chamber were explored in 1993 by the German engineer Rudolf Gantenbrink using a crawler robot he designed, Upuaut 2. After a climb of 65 m (213 ft),[30] he discovered that one of the shafts was blocked by limestone "doors" with two eroded copper "handles". Some years later the National Geographic Society created a similar robot which, in September 2002, drilled a small hole in the southern door, only to find another door behind it.[31] The northern passage, which was difficult to navigate because of twists and turns, was also found to be blocked by a door.[32]

text: Research continued in 2011 with the Djedi Project. Realizing the problem was that the National Geographic Society's camera was only able to see straight ahead of it, they instead used a fibre-optic "micro snake camera" that could see around corners. With this they were able to penetrate the first door of the southern shaft through the hole drilled in 2002, and view all the sides of the small chamber behind it. They discovered hieroglyphs written in red paint. They were also able to scrutinize the inside of the two copper "handles" embedded in the door, and they now believe them to be for decorative purposes. They also found the reverse side of the "door" to be finished and polished, which suggests that it was not put there just to block the shaft from debris, but rather for a more specific reason.[33]

text: Grand Gallery

text: The Grand Gallery continues the slope of the Ascending Passage, but is 8.6 metres (28 ft) high and 46.68 metres (153.1 ft) long. At the base it is 2.06 metres (6.8 ft) wide, but after 2.29 metres (7.5 ft) the blocks of stone in the walls are corbelled inwards by 7.6 centimetres (3.0 in) on each side. There are seven of these steps, so, at the top, the Grand Gallery is only 1.04 metres (3.4 ft) wide. It is roofed by slabs of stone laid at a slightly steeper angle than the floor of the gallery, so that each stone fits into a slot cut in the top of the gallery like the teeth of a ratchet. The purpose was to have each block supported by the wall of the Gallery, rather than resting on the block beneath it, in order to prevent cumulative pressure.[34]

text: At the upper end of the Gallery on the right-hand side there is a hole near the roof that opens into a short tunnel by which access can be gained to the lowest of the Relieving Chambers. The other Relieving Chambers were discovered in 1837–1838 by Colonel Howard Vyse and J. S. Perring, who dug tunnels upwards using blasting powder.

text: The floor of the Grand Gallery consists of a shelf or step on either side, 51 centimetres (20 in) wide, leaving a lower ramp 1.04 metres (3.4 ft) wide between them. In the shelves there are 54 slots, 27 on each side matched by vertical and horizontal slots in the walls of the Gallery. These form a cross shape that rises out of the slot in the shelf. The purpose of these slots is not known, but the central gutter in the floor of the Gallery, which is the same width as the Ascending Passage, has led to speculation that the blocking stones were stored in the Grand Gallery and the slots held wooden beams to restrain them from sliding down the passage.[35] This, in turn, has led to the proposal that originally many more than 3 blocking stones were intended, to completely fill the Ascending Passage.[citation needed]

text: At the top of the Grand Gallery, there is a step giving onto a horizontal passage some metres long and approximately 1.02 metres (3.3 ft) in height and width, in which can be detected four slots, three of which were probably intended to hold granite portcullises. Fragments of granite found by Petrie in the Descending Passage may have come from these now-vanished doors.

text: In 2017, scientists from the Scan Pyramids Project discovered a large cavity above the Grand Gallery, using muon radiography that can detect cosmic rays. Its length is at least 30 metres (98 ft) and its cross-section is similar to that of the Grand Gallery. It was detected using three different technologies: nuclear emulsion films, scintillator hodoscopes, and gas detectors.[36][37] The purpose of the cavity is not known and it is not accessible but according to Zahi Hawass it may have been a gap used in the construction of the Grand Gallery.[38] The Japanese research team disputes this, however, saying that the huge void is completely different from the construction spaces previously identified.[39]

text: King's Chamber

text: The "King's Chamber"[1] is 20 Egyptian Royal cubits or 10.47 metres (34.4 ft) from east to west and 10 cubits or 5.234 metres (17.17 ft) north to south. It has a flat roof 11 cubits and 5 digits or 5.852 metres (19 feet 2 inch) above the floor. 0.91 m (3.0 ft) above the floor there are two narrow shafts in the north and south walls (one is now filled by an extractor fan in an attempt to circulate air inside the pyramid). The purpose of these shafts is not clear: they appear to be aligned towards stars or areas of the northern and southern skies, yet one of them follows a dog-leg course through the masonry, indicating no intention to directly sight stars through them. They were long believed by Egyptologists to be "air shafts" for ventilation, but this idea has now been widely abandoned in favour of the shafts serving a ritualistic purpose associated with the ascension of the king’s spirit to the heavens.[40]

text: The King's Chamber is entirely faced with granite. Above the roof, which is formed of nine slabs of stone weighing in total about 400 tons, are five compartments known as Relieving Chambers. The first four, like the King's Chamber, have flat roofs formed by the floor of the chamber above, but the final chamber has a pointed roof. Vyse suspected the presence of upper chambers when he found that he could push a long reed through a crack in the ceiling of the first chamber. From lower to upper, the chambers are known as "Davison's Chamber", "Wellington's Chamber", "Nelson's Chamber", "Lady Arbuthnot's Chamber", and "Campbell's Chamber". It is believed that the compartments were intended to safeguard the King's Chamber from the possibility of a roof collapsing under the weight of stone above the Chamber. As the chambers were not intended to be seen, they were not finished in any way and a few of the stones still retain masons' marks painted on them. One of the stones in Campbell's Chamber bears a mark, apparently the name of a work gang.[41][42]

text: The only object in the King's Chamber is a rectangular granite sarcophagus, one corner of which is broken. The sarcophagus is slightly larger than the Ascending Passage, which indicates that it must have been placed in the Chamber before the roof was put in place. Unlike the fine masonry of the walls of the Chamber, the sarcophagus is roughly finished, with saw-marks visible in several places. This is in contrast with the finely finished and decorated sarcophagi found in other pyramids of the same period. Petrie suggested that such a sarcophagus was intended but was lost in the river on the way north from Aswan and a hurriedly made replacement was used instead.

text: Modern entrance

text: Today tourists enter the Great Pyramid via the Robbers' Tunnel, a tunnel purportedly created around AD 820 by Caliph al-Ma'mun's workmen using a battering ram.[43][44] The tunnel is cut straight through the masonry of the pyramid for approximately 27 metres (89 ft), then turns sharply left to encounter the blocking stones in the Ascending Passage. It is believed that their efforts dislodged the stone fitted in the ceiling of the Descending Passage to hide the entrance to the Ascending Passage and it was the noise of that stone falling and then sliding down the Descending Passage, which alerted them to the need to turn left. Unable to remove these stones, however, the workmen tunnelled up beside them through the softer limestone of the Pyramid until they reached the Ascending Passage. It is possible to enter the Descending Passage from this point, but access is usually forbidden.[45]

text: Pyramid complex

text: The Great Pyramid is surrounded by a complex of several buildings including small pyramids. The Pyramid Temple, which stood on the east side of the pyramid and measured 52.2 metres (171 ft) north to south and 40 metres (130 ft) east to west, has almost entirely disappeared apart from the black basalt paving. There are only a few remnants of the causeway which linked the pyramid with the valley and the Valley Temple. The Valley Temple is buried beneath the village of Nazlet el-Samman; basalt paving and limestone walls have been found but the site has not been excavated.[46][47] The basalt blocks show "clear evidence" of having been cut with some kind of saw with an estimated cutting blade of 15 feet (4.6 m) in length, capable of cutting at a rate of 1.5 inches (38 mm) per minute. John Romer suggests that this "super saw" may have had copper teeth and weighed up to 300 pounds (140 kg). He theorizes that such a saw could have been attached to a wooden trestle and possibly used in conjunction with vegetable oil, cutting sand, emery or pounded quartz to cut the blocks, which would have required the labour of at least a dozen men to operate it.[48]

text: On the south side are the subsidiary pyramids, popularly known as the Queens' Pyramids. Three remain standing to nearly full height but the fourth was so ruined that its existence was not suspected until the recent discovery of the first course of stones and the remains of the capstone. Hidden beneath the paving around the pyramid was the tomb of Queen Hetepheres I, sister-wife of Sneferu and mother of Khufu. Discovered by accident by the Reisner expedition, the burial was intact, though the carefully sealed coffin proved to be empty.

text: The Giza pyramid complex, which includes among other structures the pyramids of Khufu, Khafre and Menkaure, is surrounded by a cyclopean stone wall, the Wall of the Crow. Mark Lehner has discovered a worker's town outside of the wall, otherwise known as "The Lost City", dated by pottery styles, seal impressions, and stratigraphy to have been constructed and occupied sometime during the reigns of Khafre (2520–2494 BC) and Menkaure (2490–2472 BC).[49][50] Recent discoveries by Mark Lehner and his team at the town and nearby, including what appears to have been a thriving port, suggest the town and associated living quarters consisting of barracks called "galleries" may not have been for the pyramid workers after all, but rather for the soldiers and sailors who utilized the port. In light of this new discovery, as to where then the pyramid workers may have lived, Lehner now suggests the alternative possibility they may have camped on the ramps he believes were used to construct the pyramids or possibly at nearby quarries.[51]

text: In the early 1970s, the Australian archaeologist Karl Kromer excavated a mound in the South Field of the plateau. This mound contained artefacts including mudbrick seals of Khufu, which he identified with an artisans' settlement.[52] Mudbrick buildings just south of Khufu's Valley Temple contained mud sealings of Khufu and have been suggested to be a settlement serving the cult of Khufu after his death.[53] A worker's cemetery used at least between Khufu's reign and the end of the Fifth Dynasty was discovered south of the Wall of the Crow by Zahi Hawass in 1990.[54]

text: Boats

text: There are three boat-shaped pits around the pyramid, of a size and shape to have held complete boats, though so shallow that any superstructure, if there ever was one, must have been removed or disassembled. In May 1954, the Egyptian archaeologist Kamal el-Mallakh discovered a fourth pit, a long, narrow rectangle, still covered with slabs of stone weighing up to 15 tons. Inside were 1,224 pieces of wood, the longest 23 metres (75 ft) long, the shortest 10 centimetres (0.33 ft). These were entrusted to a boat builder, Haj Ahmed Yusuf, who worked out how the pieces fit together. The entire process, including conservation and straightening of the warped wood, took fourteen years.

text: The result is a cedar-wood boat 43.6 metres (143 ft) long, its timbers held together by ropes, which is currently housed in a special boat-shaped, air-conditioned museum beside the pyramid. During construction of this museum, which stands above the boat pit, a second sealed boat pit was discovered. It was deliberately left unopened until 2011 when excavation began on the boat.[55]

text: Looting

text: Although succeeding pyramids were smaller, pyramid-building continued until the end of the Middle Kingdom. However, as authors Brier and Hobbs claim, "all the pyramids were robbed" by the New Kingdom, when the construction of royal tombs in a desert valley, now known as the Valley of the Kings, began.[56][57] Joyce Tyldesley states that the Great Pyramid itself "is known to have been opened and emptied by the Middle Kingdom", before the Arab caliph Abdullah al-Mamun entered the pyramid around AD 820.[43]

text: I. E. S. Edwards discusses Strabo's mention that the pyramid "a little way up one side has a stone that may be taken out, which being raised up there is a sloping passage to the foundations". Edwards suggested that the pyramid was entered by robbers after the end of the Old Kingdom and sealed and then reopened more than once until Strabo's door was added. He adds: "If this highly speculative surmise be correct, it is also necessary to assume either that the existence of the door was forgotten or that the entrance was again blocked with facing stones", in order to explain why al-Ma'mun could not find the entrance.[58]

text: He also discusses a story told by Herodotus. Herodotus visited Egypt in the 5th century BC and recounts a story that he was told concerning vaults under the pyramid built on an island where the body of Cheops lies. Edwards notes that the pyramid had "almost certainly been opened and its contents plundered long before the time of Herodotus" and that it might have been closed again during the Twenty-sixth Dynasty of Egypt when other monuments were restored. He suggests that the story told to Herodotus could have been the result of almost two centuries of telling and retelling by Pyramid guides.[59]


document_title: Chevrolet Bolt

question_text: who makes the battery for the chevy bolt

text: Chevrolet Bolt

text: History[edit]

text: Development[edit]

text: GM Korea began developing the Bolt in 2012 with a team of 180 people,[12] and with its initial concept debuting at the 2015 North American International Auto Show.[13]

text: As of June 2015[update], General Motors had tested more than 50 Bolt prototypes hand-built at the General Motors Proving Grounds in Milford, Michigan. The cars were tested at the proving grounds and overseas locations for ride and handling dynamics, cabin comfort, quietness, charging capability, and energy efficiency.[14]

text: Alan Batey, head of General Motors North America, announced in February 2015 that the Bolt EV was headed for production, and would be available in all 50 states.[15] GM also has plans to sell the Bolt in select global markets.[16]

text: In January 2016, at the Consumer Electronics Show in Las Vegas, the production version of the Chevrolet Bolt was unveiled. At the show, during GM CEO Mary Barra's keynote, Chevrolet confirmed an estimated range of 200 mi (320 km) or more, around US$30,000 price after government incentives, and stated it would be available in late 2016.[17] Barra projected in February 2016 that the European version, marketed as the Opel Ampera-e, would enter production in 2017.[6]

text: In March 2016, GM released photos and a short pre-production video of the Bolt at the company's Orion Assembly plant outside Detroit, testing manufacturing and tooling.[18]

text: Profitability[edit]

text: An unnamed source cited by Bloomberg News estimates that General Motors is expected to take a loss of between US$8,000 and US$9,000 per Bolt sold. A GM spokesman first declined to comment on the expected profitability.[19] Opel refuted that in December 2016 and states that GM has battery cell costs of $130/kWh, and industry is not yet optimized for mass production.[20]

text: Production[edit]

text: Final assembly takes place at GM's Orion Assembly plant in Orion Township, Michigan,[21] which received a US$160 million upgrade for Bolt production.[16] Manufacture of the battery, motor, and drive unit started in August 2016 at LG, Incheon, South Korea.[22]

text: The car is designed for flexible production by having some of the battery in the same position as the fuel tank in internal combustion engine-powered cars, and is made on the same assembly line as the Chevrolet Sonic[23][24] at a combined rate of 90,000 per year.[25]

text: Analysts expected Bolt production at 22,000 per year, and Ampera-e at a few thousand.[26] Production may increase to 30,000 to 50,000 per year according to demand.[27] Initial regular production had begun by early November 2016[5] at a rate of 9 per hour, gradually increasing to 30/hour.[28] Retail deliveries began in California in December 2016.[8][needs update]

text: Regular production was expected to begin in October 2016 at 25,000-30,000 the first year.[29][30]

text: Design[edit]

text: The Bolt was designed from 2012 by a team of 180 people in GM's Korea[12] studio (formerly Daewoo Korea), as B-segment size[31] on its own platform, and does not share elements with the GM Gamma platform cars Chevrolet Sonic/Spark/Opel Corsa.[32][33]

text: The EPA classifies the Bolt as "small station wagon", with less than 130 cu ft of interior volume.[1][34] GM refers to the Bolt as a crossover.[35] The passenger volume is 94 cu ft (2,700 L), and cargo space is 17 cu ft (480 L)[36] (381 liter).[37]

text: The Bolt's doors, tailgate, and hood are aluminum.[31] The driver can adjust the level of regenerative braking as the accelerator pedal is lifted.[38] GM plans for "Over-the-air software updates" during 2017.[39] The front seats are asymmetrical to maximize cabin volume while accommodating airbags.[40]

text: Specifications[edit]

text: Battery[edit]

text: The Bolt's battery uses "nickel-rich lithium-ion" chemistry, allowing the cells to run at higher temperatures than those in GM's previous electric vehicles, allowing a simpler[citation needed] and cheaper[citation needed] liquid cooling system for the 60 kWh (220 MJ) battery pack. The battery pack is a stressed member and weighs 960 lb (440 kg).[41] It accounts for 23% of the car's value,[36] and is composed of 288 flat "landscape" format cells (similar in shape to cells used in other GM products, but contrasting the cylindrical 18650 and 21-70 cells used by Tesla). Cells are bundled into groups of three connected in parallel, and 96 groups connected in series compose the pack.[42] The battery is rated at 160 kW power to avoid limiting the 150 kW/340 Nm motor. GM offers a battery warranty of 8 years / 100,000 miles (160,000 km), and has no plans for other battery sizes. [20]

text: In October 2015, General Motors said they will purchase the Bolt's battery cells at a price of $145 per kilowatt hour from LG Chem, representing a minimum of $8,700 in revenue per car.[43] The cost is reportedly about $100 cheaper per kWh than the price LG was giving other customers at the time.[44][45] GM estimated a cell price of $130/kWh in December 2016.[20]

text: While initially expected to share its lithium-ion battery technology with the second generation Chevrolet Volt,[15][46] the production version of the Bolt uses batteries with a different chemistry more suited to the different charge cycles of a long-range electric vehicle, compared to the more frequent charging/discharging of hybrids and short-range EVs.[47]

text: Drivetrain[edit]

text: Other specifications include a 200 hp (150 kW) and 266 lb⋅ft (361 N⋅m) Interior Permanent Magnet electric motor, acceleration from 0–30 mph (0–48 km/h) in 2.9 seconds and 0–60 mph (0–97 km/h) in less than 7 seconds, and a top speed of 91 mph (146 km/h). The electric motor is integrated with a single-speed transmission and differential, to form a single modular drive unit that connects directly to the front axles. The single-speed transmission has a final drive ratio of 7.05:1.[48][49][50][51]

text: Body and Chassis[edit]

text: The Bolt EV is tall hatchback design, with a curb weight of 3,580 pounds (1,625 kg).[52] Despite its overall height of nearly 63 inches (1.6 meters), the center of gravity is under 21 inches (53 cm) above the ground, yielding surprisingly stable handling during cornering. The low center of gravity is due to under-floor mounting of the battery pack, following the lead of Tesla's Model S.

text: Bolt uses the now-common kammback/hatchback low-drag body design, with sweeping curves leading to an abrupt back end. It was initially reported to have a drag coefficient of Cd=0.32[31] but GM says the final production vehicle has Cd=0.308.[53]

text: Range and efficiency[edit]

text: Under the U.S. Environmental Protection Agency (EPA) five-cycle test methodology, the Bolt fuel economy is rated at 119 miles per gallon gasoline equivalent (mpg-e) (2.0 L/100 km) for combined driving, 128 mpg-e (1.8 L/100 km) in city and 110 mpg-e (2.1 L/100 km) in highway.[1] Charging time is rated at 9.3 hours on a Level 2 fast charger.[54]

text: The Bolt EV has a combined EPA-rated range of 238 mi (383 km).[1] For city driving, the EPA rated the Bolt range at 255 mi (410 km), and due to its relative high drag coefficient, its range for highway driving is 217 mi (349 km).[57] One Bolt owner was able to drive from McHenry, Maryland in the western part of the state to Ocean City, Maryland, a distance of 313 mi (504 km), on a single charge.[58]

text: The Ampera-e has a certified range of 320 mi (520 km) under the New European Driving Cycle (NEDC) test cycle with a full battery, and achieved a range of 240 mi (380 km) under the more strict Worldwide harmonized Light vehicles Test Procedures (WLTP).[2] Opel expected the Ampera-e to achieve a NEDC range of about 500 km (310 mi).[59]

text: Until July 2017, the Bolt is the only plug-in electric car with a manufacturer's suggested retail price (MSRP) of less than US$50,000 capable of delivering an EPA-rated range of over 200 mi (320 km).[56] All other electric cars below that price threshold and available for retail sales, except the Tesla Model 3, can only go 60 to 125 mi (97 to 201 km) on a single charge.[54][56] The Bolt also surpasses the range of Tesla's entry-level Model S 60 sedan, which has an EPA-rated range of 210 mi (340 km).[60] Among all-electric series production cars sold in the U.S., in addition to the Model 3, only the Tesla Model S sedan and Model X crossover can go more than 200 mi (320 km).[54]

text: The Renault Zoe with the optional 41 kWh battery has a range of up 400 km (250 mi) under the NEDC cycle, but Renault clarified the upgraded battery delivers a real-world range of 300 km (190 mi) in urban or suburban areas.[61][62]

text: Charging[edit]

text: All models of Bolt support standard SAE EV charging plugs, at Level 1 or Level 2 (AC). A factory option supports Level 3 (rapid DC) charging with the SAE Combo DC system. A portable Level 1 charging adapter is supplied with each Bolt, stowed in a special compartment under the hatchback floor.

text: Level 1 (110VAC) charging supplies roughly 1 kW[37] and adds 3–5 miles (5–8 km) of range per hour of charging. Level 2 (240VAC) charging supplies up to 7.2 kW[37] and adds 20–30 miles (30–50 km) of range per hour of charging. Level 3 charging with the factory-option 80 kW SAE Combo DC fast charging system can add 90 mi (140 km) of range in 30 minutes, or fill the battery to 80% capacity in an hour. The Bolt user manual suggests fast-charging to only 80% charge to ensure consistent 50 kW charging.[24][63]

text: Tires[edit]

text: The Bolt EV is delivered with self-sealing tires whose interior surfaces are coated with a sticky compound to automatically seal small leaks and punctures in the tread area.[64] There is no spare tire, nor is there (officially) a place to store one.[65] The car is equipped with a digital Tire Pressure Monitoring System to warn the driver if a tire is leaking, and a portable inflator kit is available as a standard part. Under the rear hatchback cargo deck, there is a space that can be used to store an undersized spare, and some owners carry a compatible Chevy Cruze spare tire there.[66]

text: Test drives[edit]

text: The EPA-rated range of 238 mi (383 km) was confirmed by automotive reporters driving a preproduction Bolt with a 60-kWh battery. Driven under different driving modes with the air conditioning on, the trip between Monterey and Santa Barbara was completed with an energy consumption of 50.1 kWh, representing an average efficiency of 4.8 miles per kWh (12.9 kWh/100 km). A total of 237.8 mi (382.7 km) were driven, with the Bolt's display showing 34 mi (55 km) of range remaining.[67] Several other journalists conducted a preproduction Bolt test drive on the same route, and all reported similar results regarding the Bolt EPA-estimated range.[60][68][69][70][71]

text: As part of its debut at the 2016 Paris Motor Show, Opel reported driving an Ampera-e without recharging from Piccadilly Circus in London to Porte de Versailles in Paris, the venue of the exhibition. The rebadged Bolt traveled 417 km (259 mi) with 80 km (50 mi) of range remaining.[59][72]

text: Markets and sales[edit]

text: United States[edit]

text: Ordering began in California and Oregon in mid-October 2016.[73] The first three Bolts were delivered in the San Francisco Bay Area on December 13, 2016,[8] and a total of 579 units were delivered in 2016.[74] Availability was rolled out gradually across the United States, and by August 2017 the car was available nationwide.[8]

text: Demand profile did not exactly match predictions, leading GM to slow production in July 2017.[75] However, in the last months of 2017 Bolt demand rose rapidly, by October, it outsold any other model of electric car, including those from Tesla.[76] Sales totaled 23,297 units in 2017, making the Bolt the U.S. second best selling plug-in car in 2017 after the Tesla Model S (~26,500).[74][77] In California, the Bolt listed as the top selling plug-in car with 13,487 units delivered, ahead of the Tesla Model S, listed second with 11,813.[78] The Bolt also led the state's subcompact segment in 2017, with a market share of 14.7% of all new cars sold in this category.[79] As of February 2018[update], cumulative sales in the American market totaled 26,477 units.[74]

text: Canada[edit]

text: The Bolt has been available in Canada since the beginning of 2017. A total of 2,122 Bolt EVs were sold in Canada in 2017.[74]

text: Norway[edit]

text: The Ampera-e launch in the Norwegian market was scheduled for April 2017, when 13 were registered.[80][81] Deliveries to retail customers[24] began on May 17, 2017.[82] Over 4,000 cars were ordered in Norway, with some to be delivered in 2018.[7] Registrations totaled 1,121 units in 2017.[83]

text: South Korea[edit]

text: In South Korea, General Motors opened the order books on March 18, 2017, and all 400 units of the first allotment were sold out in 2 hours.[84]

text: Awards and recognition[edit]

text: The Bolt won the 2017 Motor Trend Car of the Year award,[85] the 2017 North American Car of the Year,[86][87] the 2017 AutoGuide.com Reader's Choice Green Car of the Year,[88] and the Green Car Reports Best Car To Buy 2017.[89] The Bolt also ended up Car & Driver's '10 Best Cars' list for 2017 [90][better source needed] The Chevy Bolt also won the 2017 Green Car of the Year awarded by the Green Car Journal.[91] It was also named by Time Magazine among its list of 25 Best Inventions of 2016,[92] and among Popular Science's 10 Greatest Automotive Innovations of 2016.[93] The Bolt EV beat out the Cadillac CT6 and Jaguar XE to win the Detroit Free Press award for Car of the Year.[94][better source needed] Automobile magazine included the Bolt in its 2017 All Star list.[95]

text: Pre-production name confusion[edit]

text: In 2015, Chevrolet acknowledged confusion between two vehicles with a similar-sounding names; Bolt and Volt.[96]

text: Chevrolet's marketing chief, Tim Mahoney, subsequently announced GM would keep the Bolt name.[97]

text: Autoblog projected similar confusion among European customers where the Opel Ampera-e (the Bolt variant) is just one letter off from the Opel Ampera, the previous-generation Chevrolet Volt sold in Europe — suggesting the names could confuse customers who think the new all-electric hatchback is closely related to the old plug-in hybrid hatchback.[98]

text: Tata Motors has had a car named the Bolt on the market since 2014, and has registered the trademark in India and other countries.[99]

text: If Chevrolet wants to sell the Bolt in India it would need to call it a different name due to the trademark Tata owns for its car or it license the name from Tata.[citation needed]


document_title: Book of Signs

question_text: what are the 7 miracles in the gospel of john

text: Book of Signs

text: Location in text[edit]

text: There is a widespread scholarly view that John's gospel can be broken into four parts: a prologue, (John 1:-1:18), the Book of Signs (1:19 to 12:50), the Book of Glory (or Exaltation) (13:1 to 20:31) and an epilogue (chapter 21).[1]

text: John 20:30 Therefore many other signs Jesus also performed in the presence of the disciples, which are not written in this book; 31 but these have been written so that you may believe that Jesus is the Christ, the Son of God; and that believing you may have life in His name.

text: It is this indication by the author of the gospel that the signs are selected, which leads to the examination of them as a sequence of seven.

text: Seven signs[edit]

text: The seven signs are:[2]

text:
Changing water into wine at Cana in John 2:1-11 - "the first of the signs"
Healing the royal official's son in Capernaum in John 4:46-54
Healing the paralytic at Bethesda in John 5:1-15
Feeding the 5000 in John 6:5-14
Jesus walking on water in John 6:16-24
Healing the man blind from birth in John 9:1-7
The raising of Lazarus in John 11:1-45

tag: ol

text: The seven signs are seen by some scholars and theologians as evidence of new creation theology in the Gospel of John, the resurrection of Jesus being the implied eighth sign, indicating a week of creation and then a new creation beginning with the resurrection.[3]

text: Crucifixion as the seventh sign[edit]

text: Others, such as John Marsh and Stephen Smalley, have suggested six initial signs (seeing the walking on the water as part of feeding the 5000, rather than a separate sign in itself), and that the seventh sign is the crucifixion of Jesus.[4]

text: Eighth sign[edit]

text: Others, such as John Hutchinson[5] and E. W. Bullinger, have emphasized a sequence of eight signs, concluding with the miraculous catch of fish in John 21:1-14.[6]