Working with the Command-Line Interface Chapter 18
Overview In this chapter, you will learn how to Explain the operation of the command-line interface Execute fundamental commands from the command line Manipulate files and folders from the command line
Historical/Conceptual IBM invented the PC in the late ‘70s but needed an operating system. Digital Research had an OS but turned them down IBM went to a small company (Bill Gates at Microsoft) that had created BASIC. Microsoft had never written an OS but accepted the challenge. Gates found an OS called Quick-and-Dirty-Operating-System (QDOS) and purchased it from the person who wrote it. Microsoft released it as MS-DOS V 1.1 (Microsoft Disk Operating System). MS-DOS 6.22 ultimately released in 1994. DOS used a command-line interface.
Command-Line Interface (CLI) How does a command-line interface work? It begins with a prompt indicating the computer is ready to do something (such as C:\>). The user types in a command and presses ENTER. The command is executed. A new prompt is displayed—ready for the next command. CLI executes commands just as the Windows GUI does. In CLI, you type the command and press ENTER. In GUI, you point and click to execute commands.
Command-Line Interface (continued) Figure 2: Contents of C: in Computer—Icon view Figure 1: Contents of C: directory from the command line
Command-Line Interface (continued) Figure 4: Contents of C: in Computer—Details view Figure 3: Selecting Details view in Computer
Accessing the Command Line Use the Run dialog box or Start Search text box Start | Run Type cmd(or) Type command Either runs the cmd.exe executable program found in %systemroot%\system32 You can also access the command line through the Start | All Programs menu. Figure 5: Type cmd in the Run dialog box to open a command-line interface window in Windows XP.
Accessing the Command Line (continued) Figure 6: The command-line interface window with a C:\ prompt Figure 7: The Windows Vista/7 command-line interface window
The Command Prompt The command prompt is always focused on a specific folder. Commands operate on the files and folders in the folder on which the command line is focused. You can first focus on the drive and folder where you want to work to make commands simpler. Figure 8: Command prompt indicating focus on the C:\Diploma\APLUS\ folder
Filenames and File Formats Each program or piece of data is stored as a file on the drive. Filenames have two parts: Filename In DOS, up to 8 characters long Extension In DOS, up to 3 characters long Optional The filename and extension are separated by a dot Called the 8.3 naming system These characters cannot be used today: / \ < > | : " * ?
Filenames and File Formats Windows does not restrict the filename to 8.3 (it can be up to 255 characters). To be backward-compatible with DOS, you need to follow the 8.3 standard. Windows creates two filenames for every file to ensure backward-compatibility. The extension tells the computer the type of file. .exe, .doc, .xls .gif, .jpg, .png .chm (help file)
Filenames and File Formats (continued) Figure 10: One file has no extension. Figure 9: What kind of file is the one on the lower right?
File Formats All files are written in binary format. Different programs have unique methods of reading and writing, so one program may or may not understand files from another program. Need for a universal format American Standard Code for Information Interchange (ASCII) used for text First universal file format Defines 256 8-bit characters Unicode Uses 16-bit code to cover every character for the most common languages First 256 characters are the ASCII characters
ASCII Character Chart Figure 11: ASCII characters
Folders and Files Folders and files must be unique. Can’t use the same name in the same folder. C:\ represents the root directory of C. To describe a subfolder, add the name of the folder: C:\TEST The location of a file is called the path. The path of C:\test\file.txt is C:\test
Structure: Syntax and Switches The command line requires the exact syntax for each command. Type the name of the command and the desired or allowed switches, and then press ENTER to execute the command. Switches modify the behavior of the command. Multiple switches may be allowable. DIR /W /Pdisplays the directory in wide mode and one page at a time.
Help Help with any command is readily available in one of three ways. HELP gives a one-line description of the command. HELP [command]gives specific help for the command. [Command] /? gives specific help for the command.
dir Command The dir command lists the contents of a particular directory The dir /w command lists only the folder and file names Figure 12: Results for dir in a user’s folder
dir Command Switches Figure 13: Typing dir /? lists all possible switches for the dir command
Directories: cd Command The cd (or chdir) command is used to change the focus to a different directory. The cd\ command is used to return to the root directory. Type cd [folder name] and then press ENTER to change focus to that folder or directory. Type cd.. and press ENTER to go up one directory. To switch between drives, type the drive letter followed by a colon, and then press ENTER. C: D:
Making and Removing Directories The md (or mkdir) command is used for creating a directory. The del command is used for deleting files, and the rd (rmdir) command is used for deleting directories and subdirectories. rd /s will removed populated folders and their contents.
Lab – Making and Removing Folders Change focus to root Create three folders class docs backup Create a subfolder in backup temp Delete rd the temp folder Use dir to check each step
Running a Program To run a program Change the prompt focus to the directory where the program is stored: cd c:\windows\system32 Type the filename with or without its extension and press ENTER: edit.com
Running a Program (continued) Figure 15: Running mem in Windows Vista 32-bit Figure 14: The mem.exe program displayed in the System32 folder
Start at the Root What's in your root directory? Double-click C: drive in My Computer. Hey! Where are the Windows system files, like NTLDR and BOOT.INI? Could go to Folder Options and display hidden and system files, or could go to the prompt. DIR /P still doesn’t show the system files, so we need a new tool.
Working with Files Attributes (H, R, S, A) are special values assigned to a file: Hidden: hides the file Read-only: protects a file from being deleted or modified System: identifies system files Archive: identifies files that have not been backed up The attrib.exe program is used to inspect and change file attributes.
attrib attrib can be used to change the attributes. Use + to add attribute. Use – to remove attribute. attrib +r ailog.txt Makes the file read only. attrib –h ailog.txt Makes the file no longer hidden.
Working with Files Wildcards Wildcards are special characters that enable commands to act on more than one file at a time. The * represents any number of characters. The ? represents a single character. dir *.txt Lists all files that end in .txt dir *.?xt Lists all files that end in xt
Working with Files (continued) ren is used to rename files. del and erase are used to delete files. copy is used to make a copy of the file in a new location. move is used to move the file to a new location. xcopy is used when working with multiple directories.
Working with Files (continued) Figure 17: Success at last Figure 16: Rename failed me
Working with Files (continued) robocopy is a newer command included in Windows Vista and 7. Allows many different functions beyond copy and xcopy: Copies encrypted files Duplicates source directories Allows administrators to copy even when denied permissions to files Resumes copying after an interruption
Mike’s Five-Step copy/move Process Point the command prompt to the directory containing the files to be copied or moved. C:\>cd \docs 2. Type copy or move and a space. C:\DOCS>copy 3. Type the name(s) of the file(s) to be copied/moved and a space. C:\DOCS>copy *.doc 4. Type the path of the new location for the files. C:\DOCS>copy *.doc c:\Steam 5. Press ENTER.
Useful Utilities chkdsk (/f /r) Runs the command-line version of error-checking. Run to recover from accidental shutdown, such as during a disk defragmentation. format Normally done from the GUI, but can do this quickly from the CLI. format x: /q is a great way to wipe a drive. hostname Used to display the name of your computer, also known as the hostname.
Useful Utilities (continued) Figure 18: The chkdsk /f /r utility and switches on a locked drive Figure 19: Using format /? at the command prompt
Useful Utilities (continued) sfc System File Checker helps restore Windows files. sfc /scannow from a command prompt Figure 20: Checking sfc options with sfc /? at a command prompt
Using Special Keys F1 function key brings back the previous command one letter at a time. F3 function key brings back the entire command at once. Arrow keys You can also use the arrow keys (up and down) to scroll through commands. Arrow keys (left to right) enable you to edit commands.
compact Command compact Displays or alters the compression state of files. compact /c Figure 21: The compact command with no switches
compact Command (continued) Figure 23: The contents of C:\Compact have been compressed Figure 22: Typing compact /c compresses the contents of the directory
compact Command (continued) Figure 24: Typing compact /u "Session 1.ppt" decompresses only that file
cipher Command cipher Displays or alters the encryption state of files. /e specifies encryption operation. /a says to apply it to the files as well as the directory. Figure 25: Typing cipher /e /a encrypts the contents of the directory
cipher Command (continued) Figure 27: Typing cipher /d /a dsc_4255.dng decrypts only that file Figure 26: The cipher command confirms that the files were encrypted
PowerShell PowerShell Introduced in Windows XP and improved in Windows 7. Powerful addition to traditional command-line interface. Uses powerful tools called cmdlets. Syntax is slightly more complex than regular command-line use. In Windows 7, type powershell in search bar. In XP/Vista, you must download from Microsoft and have the .NET 2.0 framework installed.
PowerShell (continued) Figure 28: Simple commands in PowerShell