The document discusses external commands in DOS such as FORMAT, CHKDSK, SCANDISK, XCOPY, ATTRIB, DISKCOPY, PRINT, TREE, and DELTREE. External commands are stored on disk and loaded when used, making them slower than internal commands. The document provides examples and explanations of several external commands and their functions, such as formatting disks, checking disks, copying disks, copying files/folders, changing file attributes, and deleting trees of files/folders. It also includes a quiz to test the reader's understanding.

1. External commands
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2. Objective
On completion of this period, you would be
able to know
External commands-FORMAT,
CHKDSK, SCANDISK etc
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3. Recap
What are internal commands?
Internal commands are built – in
commands
Examples: COPY, DEL, DIR, TYPE, CD, MD,
RD, MODE, PATH, DATE, TIME, COPY CON
etc
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4. Prerequisite
What is meant by commands
Instructions used to communicate with the
computer system
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5. External Commands
 External commands are included in a set of
programs called utility programs that are stored
on a disk
 When these commands are used, DOS loads
appropriate utility programs from disk and then
executes them
 As a result, external commands are executed
much more slowly than internal commands
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6. External Commands (contd)
 CHKSDK [d:]
• This command is used for checking the
disk and reporting back the status of the
system
• It checks for the memory and gives the
detailed information about the memory
consumed as well as free memory
Example :
CHKDSK A:
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7. External Commands (contd)
 DISKCOPY [d:] [d:]
used to copy a diskette into another. This
makes the diskette in the first drive on the
diskette in another drive
Example:
DISKCOPY A: B:
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8. External Commands (contd)
 DISKCOMP [d:] [d:]
• Compare the contents of two diskettes on the
drives specified
• If there is any difference in the contents of the
disks, it gives the message
• Otherwise it asks to compare any other disks
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9. External Commands (contd)
 TREE [d:] [/F]
This is used to display all the directories and
subdirectories. /F displays all files if specified
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10. External Commands (contd)
 PRINT: [d:] [path] filename
• This command is used for printing the
contents of documents or files
• This command sends the document or the
file specified to the printer for printing
Example
C:>PRINT D:DOSLETTERMY
LETTER.LET
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11. External Commands (contd)
 FORMAT [d:] [S] [V]
• This command is used to prepare a fresh
diskette to be used by the DOS for all its
storage purposes
• It divides the disk into tracks and segments
so that the data can be stored
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12. External Commands (contd)
• If we want to create a system diskette
.i.e., a booted diskette which can be
used to boot a system as it has the basic
operating system in it, use ‘S’ as option
• This V to create a label
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13. External Commands (contd)
 DEL TREE [d:] [path]
This command is used to delete the directory
including all the sub directories and the files
This command has to be used carefully as it is
dangerous such that it deletes all the files and
subdirectories permanently
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14. External Commands (contd)
 XCOPY [drive1:] pathname1 [drive2:] pathname2
It copies files and directories, including
lower level directories
Where drive1 & pathname1 is the source
file or directory, drive2 & pathname2 is the
target file or directory
It is similar to copy command but it also
copies all the subdirectories including
empty directories
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15. External Commands (contd)
Example
C>XCOPY A: /S
Result
The above command is used to copy all files
and subdirectories on the disk in drive A to the
disk in the drive C
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16. External Commands (contd)
 ATTRIB [+R | -R] [+A | -A] [+S | -S] [+H | -H]
[drive:] [path] [filename] [/S [/D]]
It displays or changes file attributes
+ Sets an attribute
- Clears an attribute
R Read-only file attribute
A Archive file attribute
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17. External Commands (contd)
S System file attribute
H Hidden file attribute
[drive:] [path] [filename] It specifies a file for
attrib to process
/S Processes matching files in the current folder
and all subfolders
/D Processes folders as well
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18. Summary
In this class, you have learnt about
 External commands – FORMAT, CHKDSK,
SCANDISK, XCOPY, ATTRIB, DISKCOPY,
PRINT, TREE, DELTREE etc
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19. Frequently Asked Questions
1. List any four DOS external commands
2. What is DOS external command?
3. Explain any four external commands in DOS.
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20. Quiz
 C>XCOPY A: /S - This command is used to
copy all files and subdirectories on the disk in
a. drive A to the disk in the drive C.
b. drive C to the disk in the drive A.
Answer: a
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21. Quiz
 The command used to copy a diskette into
another
a. DISKCOPY
b. XCOPY
Answer: a
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