Command Line Interface. 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. How does the Command Line Work?.
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
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
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
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
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
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
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
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
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
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
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
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
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
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
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\
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
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
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
Running a Program • Change focus of prompt to the folder where program is located • Type name of program • Press ENTER
Working with Files • All files have 4 basic attributes: • Hidden • Read-only • System • Archive • Refer to photocopy for specific example of attribute command
Renaming Files • REN or RENAME command (refer to photocopy for example)
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
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)
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.
DOS Boot Sequence and Files • Three core programs • IO.SYS • MSDOS.SYS • COMMAND.COM • Two optional startup files • CONFIG.SYS • AUTOEXEC.BAT
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.
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.
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.
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.
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.
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.
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.
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.
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.
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.
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.
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.
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.
BUFFERS COUNTRY DEVICE DEVICEHIGH DOS FCBS FILES INSTALL LASTDRIVE CONFIG.SYS Commands • MOUSE.SYS • NUMLOCK • SHELL • SWITCHES
DOSKEY ECHO KEYB MOUSE.EXE PATH PAUSE PROMPT AUTOEXEC.BAT Commands • SET • SHARE • SMARTDRV
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.
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
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
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.