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Command Line Interface

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Command Line Interface

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  1. Command Line Interface

  2. Lecture Objectives • Explain the operation of the command line interface • Execute fundamental commands from the command line interface • Manipulate files and folders from the command line

  3. How does the Command Line Work? • Similar to Instant Message conversation with computer • The prompt indicates that the computer is ready to receive a command • Command is typed and ENTER is pressed • PC executes command • Prompt is displayed, indicating that the computer is waiting for the next command

  4. Accessing the Command Line • Run dialog box • Start menu under Programs | Accessories • Win 9x/Me link is named MS-DOS prompt • Win NT, 2000, XP link is called Command Prompt • To close command line interface • Type Exit at command line and press enter • Close the window

  5. Command Prompt • VERY IMPORTANT: The command prompt is always focused on a specific folder. Any commands executed are performed on the files in the folder on which the prompt is focused. Examples: C:\> root directory of C: drive C:\Diploma\APLUS> You must focus the prompt on the drive and folder where you want to work

  6. Filenames and File Formats • In Windows, each program and piece of data is stored as an individual file • Each file has a name, stored with the file on the drive • Names have 2 parts: filename and extension

  7. Eight-dot-Three naming system • File name cannot be more that 8 chrs • Extension can be up to 3 chrs, OPTIONAL • Following chrs cannot be used in filename or extension: • / \ [ ] | = + ; , * ? And division symbol

  8. Windows naming rules • All versions starting with Win 9x are not limited be 8.3 • Filenames up to 255 chrs • Win 9x has backward compatibility with DOS by creating 2 names for every file, 8.3 name and a long file name if necessary

  9. File extensions • Describes the type or function of the file • COM = command, EXE = executable • Anything that is not a program is a data file used by a program • Extension of a data file indicates which program uses that data file • .DOC = MSWord, .PPT = PowerPoint • Graphic file extensions represent the graphic standard used to create the image • .JPEG =Joint Photographic Experts Group

  10. File Formats • All files stored on hard drive in binary format • Every program is unique in the way it reads and writes this binary data • Each unique way of binary organization is known as a file format • One program cannot read another programs files unless it can convert the other programs format

  11. Drives and Folders • To execute commands from the command line, must focus the prompt at the specific drive and folder that contains the files or program with which you want to work • At boot, Win assigns letters to drives and drive partitions

  12. Hierarchical Directory Tree • All files are put in groups called folders • Any file not in a folder within the tree is said to be in the root directory • A folder inside another folder is called a subfolder • Any folder can have multiple subfolders

  13. Hierarchical Directory Tree • Hard drive is represented by C: • Root directory is indicated by \, C:\ • Subdirectories/Subfolders are indicated by adding \ and the directory name • Exact location of a file is known as its PATH

  14. Fundamental Commands • ALL commands use similar structure and execute in the same way • Name of command , target of command followed by any switches (extra numbers or letters at the end) • Typing the command followed /? Displays help menu describing syntax and possible switches

  15. DIR Command • Contents of the directory where the prompt is focused • Lists the following: • Filename • Extension • File size in bytes • Creation date/time • DIR/W command shows you only the file names • DIR/? Shows the help menu

  16. CD Command (Directories) • Change focus of command prompt to a different directory • CD\ followed by directory name • If directory does not exist, error message • Invalid Directory • The system cannot find the path specified • Return to root directory by typing CD\

  17. Moving Between Directories • CD NOT used to move between drives • Type drive letter followed by colon • If drive does not exist: • Invalid drive specification • The system cannot find the specified drive

  18. Making Directories • To make a directory • To make a directory called QUAKE3 under root directory: C:\>MD QUAKE3, press ENTER • If command is successfully executed, the command prompt will be displayed • Use DIR to verify that directory was created

  19. Removing Directories • Reverse of MD • Go to directory that contains the subdirectory you want to delete • Execute RD command • RD will not delete directory if it contains subdirectories or files

  20. Running a Program • Change focus of prompt to the folder where program is located • Type name of program • Press ENTER

  21. Working with Files • All files have 4 basic attributes: • Hidden • Read-only • System • Archive • Refer to photocopy for specific example of attribute command

  22. Renaming Files • REN or RENAME command (refer to photocopy for example)

  23. Delete Files • Use DEL command • Careful! No recycle bin. • Erased file can only be recovered using Norton Unerase • Can delete multiple files using wild cards

  24. Copying and Moving Files • Focus prompt on directory containing the file or folder to be copied • Type COPY or MOVE and a space • Type name(s) of the file(s) to be copied/moved and a space • Type the path of new location for the files (Refer to example on photocopy)

  25. The Software Core

  26. A Short History of MS-DOS

  27. Understanding DOS • All versions were built for a specific class of CPU. • MS-DOS never overcame critical limitations. • All versions used a command-line interface. • You must use the DOS prompt to set up a new system or hard disk drive.

  28. DOS Boot Sequence and Files • Three core programs • IO.SYS • MSDOS.SYS • COMMAND.COM • Two optional startup files • CONFIG.SYS • AUTOEXEC.BAT

  29. Summary of Steps in Booting the System • The power-on self test (POST) runs and invokes the operating system (OS). • The read-only memory basic input/output system (ROM BIOS) looks for an OS and checks for IO.SYS and MSDOS.SYS. • The OS processes CONFIG.SYS, if present. • COMMAND.COM is loaded. • The OS processes AUTOEXEC.BAT, if present. • COMMAND.COM presents the active-drive prompt.

  30. The DOS File System • The file is the primary unit of data storage. • Files are organized into directories. • File and directory names can be up to eight characters long, followed by a period and a three-character extension. • Some universal extensions are .exe, .com, .sys, .bat, .txt, .doc, and .drv. • File and directory names are not case-sensitive.

  31. The Evolution of Microsoft Windows • Early versions presented a graphical user interface (GUI) for MS-DOS. • Microsoft Windows 3.11 was the last 16-bit OS and the most well known version. • Microsoft Windows 95 was the first 32-bit version. • All applications designed for Windows have standard interfaces. • Multitasking allows users to have more than one application open.

  32. Operating Modes • Real mode could address only 1 MB of random access memory (RAM). • Standard mode allowed programs to run in protected mode. • In protected mode, programs could address up to 16 MB of RAM. • 386 enhanced mode could address up to 4 GB of RAM. • Certain applications included a Windows runtime version.

  33. Windows Resource Management

  34. Memory Paging and Virtual Machines • Virtual memory is an area on the hard disk drive (called a swap file) that the system uses to store program code temporarily. • Virtual machines (VMs) allow multiple programs to operate. • DOS programs run individually in separate VMs.

  35. Windows Operating Systems • Microsoft Windows for Workgroups 3.11 is an upgrade to Microsoft Windows 3.1. • Windows 95, Microsoft Windows 98, and Microsoft Windows Me can be networked easily. • Microsoft Windows NT is designed for networking. • Microsoft Windows 2000 replaces Windows NT. • Upgrading to Windows NT or Windows 2000 could present compatibility problems with some hardware and applications.

  36. The COMMAND Command • MS-DOS uses a text-based command-line user interface. • A text-based interface requires no drivers because display functions are built in. • COMMAND.COM provides the user interface.

  37. Working with the Prompt • Typing PROMPT /? or HELP PROMPT provides help information. • DOS HELP returns information on customizing the prompt and the information that appears.

  38. Internal and External Commands • External commands exist as separate files. • Windows has its own set of system utilities. • Internal commands are contained within COMMAND.COM. • Command mode requires typing a command instead of clicking an icon.

  39. DOS Mode Navigation and File Management • The DOS file system uses a tree structure. • A fully qualified path is the list of directories from the root to the file. • The DIR command displays the contents of the current or a specified directory. • DOS does not support Windows long filenames. • The MD command creates a new directory.

  40. The PATH Command • PATH allows you to display and change the search path. • %PATH% appends the old path to the new path. • Programs in path directories can be run from any location on the computer.

  41. Creating a Batch File • A batch file is an executable file that runs a series of existing commands or applications. • Commands listed in the file are executed in sequence. • Any executable that can be run from the prompt can be included in a batch file.

  42. Renaming a File • The RENAME or REN command allows you to rename a file. • The CD command allows you to change directories. • The CLS command clears the screen.

  43. Using Edit

  44. Summary of DOS Terminology



  47. File System Basics • The file system organizes data on the storage medium. • Different media require different file systems. • File systems define naming conventions, file size, and media capacity. • Magnetic media employ several different file systems, depending on the OS.

  48. Block Boot disk Boot sector Cluster Dual boot Encryption End-of-file (EOF) marker File File allocation table (FAT) File format File handle File locking Key File System Terms • Partition table • Primary partition • Sector • Track • Volume • Filename • Folder • Format • Low-level format • Master boot record

  49. Comparing and Choosing File Systems • Decision factors: • Dual boot requirement • Number and size of hard disk drives • Size of partitions • Need to support legacy applications • Need for advanced features such as security

  50. FAT-Based File Systems • All modern PCs can use FAT. • FAT organizes files by listing them in a table. • Two copies of the table are maintained on the media. • FAT was developed for and is still used by floppy disk drives. • There are three versions: FAT12, FAT16, and FAT32.