DOS Operating System

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DOS Operating System

• Ref Davis Rajkumar, Chp. 7

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Overview

• Uses of DOS
• Command window
• DOS commands
• File system
• Batch files
• Returning to Windows

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Uses of DOS

• Understanding heritage of Windows limitation
• Troubleshooting
• Scripting startup activities or launch of console
  programs, such as Java programs

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Launching Command Window

• Command line interface for Windows
• To access
• Select "Run" option under "Start" button
• Type cmd.exe in input file of dialog box
• OR
• Select "Command Prompt" from Start All Programs
  Accessories menu

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Command Window
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Command Window Utilities

• date display or set date
• time display or set time
• title set title on Command Window
• prompt set prompt in Command Window
• help list all DOS commands
• echo display string or write string to file

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File System

• DOS uses hierarchical file system
• Each storage device has root directory
• C\ -- hard drive
• A\ -- floppy drive
• F\ -- memory stick
• Type drive letter and colon at command prompt to
  change default drive, F
• Each directory can hold directories or files
• Tree command will list directories,
  sub-directories, and files

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Tree of Memory Stick
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Path

• Absolute
• Lists all directories from root to target file
• F\general\MomDad\Receipt\slice.gif
• Relative
• Lists directories from current working directory
• .\Receipt\slice.gif
• This directory "."
• Parent directory ".."

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Path Commands

• path lists current search path
• path PATHnew_path adds path to search path
• subst associates path with drive letter

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Name Restrictions

• Short names
• Eight dot three limit of eight character name
  and three character extension
• 460Files directory name
• DOS_Lab.txt file name
• Legal characters
• Letters and digits A..Z, a..z, and 0..9
• ' ( ) _at_ ! _
• No spaces allowed

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Conventional File Extensions

• ASM - assembler code
• BAK - backup file
• BAS - Basic code
• BAT - batch file
• BIN - binary file
• COB - COBOL code
• COM - command file
• DAT - ASCII data
• DIF - difference file
• DOC - ASCII document
• DVD - device driver

• EXE - executable image
• FOR - FORTRAN code
• LIB - library source
• LST - ASCII list file
• MAP - ASCII load module
• OBJ - object module
• OVR - overlay file
• REF - cross reference
• TMP - temporary link
• - temporary work

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Directory Commands

• cd change directory
• mkdir make new directory in current working
  directory
• rmdir remove a directory
• dir list content of a directory
• tree list directory hierarchy

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File Commands

• type display content of file
• del delete one or more files
• erase delete one or more files
• copy copy one or more files
• move move one or more files
• rename change name of a file

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Batch Files

• ASCII file of DOS commands
• Executable
• Used to script a task
• Execute a Java application
• Installation scripts
• Setting up specialized environments
• AUTOEXEC.BAT executes when system boots

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Pipe

• Pipe connects commands together
• MORE displays screen of data at a time
• DIR lists content of directory
• DIR MORE displays content of directory one
  screen full at a time
• is pipe symbol

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Redirection

• Redirection changes destination of output
• gt is redirection symbol
• dir gt DirList.txt writes list of current
  working directory content to "DirList.txt" file
• dir f\general gtgt DirList.txt appends list of
  f\general directory content to DirList.txt file
• gt creates or overwrites file
• gtgt appends to file

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Returning to Windows

• To exit Command Window graciously,at prompt
  type
• exit

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Summary

• DOS is command line interface for Windows
• Useful for troubleshooting and scripting
• Help lists all DOS commands
• DOS uses hierarchical directory structure
• In DOS path use \ to separate directories

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Questions?