EXTERNAL commands In DOS

External Commands require certain special DOS files to get executed.
External commands are MS-DOS utilities / programs. These are the .EXE or .COM programs located on our hard drive. They are normally placed under C:\DOS, the default directory. MS-DOS will load external commands if and only if we instruct to execute them at the DOS prompt and /or in a batch program.
The brief description of external commands. :-
1. APPEND Allows programs to open data files in specified directories as if 2. they were in the current directory.

3. ATTRIB Displays or changes file attributes.

4. CHKDSK Checks a disk and displays a status report.

5. CHOICE Prompts the user to make a choice in a batch program.

6. COMMAND Starts a new instance of the MS-DOS command interpreter.

7. COMP Compares the contents of two files or sets of files.

8. DBLSPACE Creates and manages drives compressed by using DoubleSpace.

9. DEBUG Starts Debug, a program testing and editing tool.

10. DEFRAG Reorganizes the files on a disk to optimize the disk.

11. DELOLDOS Deletes the OLD_DOS.1 directory and the files it contains.

12. DELTREE Deletes a directory and all the files and subdirectories in it.

13. DISKCOMP Compares the contents of two floppy disks.

14. DISKCOPY Copies the contents of one floppy disk to another.

15. DOSKEY Edits command lines, recalls MS-DOS commands, and creates macros.

16. DOSSHELL Starts MS-DOS Shell.

17. DRVSPACE Creates and manages drives compressed by using DriveSpace.

18. EDIT Starts MS-DOS Editor, which creates and changes ASCII files.

19. EMM386 Enables or disables EMM386 expanded memory support.

20. EXPAND Decompresses one or more compressed files.

21. FASTHELP Provides summary Help information for MS-DOS commands.

22. FASTOPEN Decreases the amount of time needed to open frequently used files and directories.

24. FC Compares two files or sets of files, and displays the differences between them.

26. FDISK Configures a hard disk for use with MS-DOS.

27. FIND Searches for a text string in a file or files.

28. FORMAT Formats a disk for use with MS-DOS.

29. GRAPHICS Loads a program that can print graphics.

30. HELP Provides complete, interactive Help information for MS-DOS commands.

31. INTERLNK Connects two computers via parallel or serial ports.

32. INTERSVR Starts the Interlnk server.

33. KEYB Configures a keyboard for a specific language.

34. LABEL Creates, changes, or deletes the volume label of a disk.

35. LOADFIX Loads a program above the first 64K of memory, and runs the program.

36. MEM Displays the amount of used and free memory in your system.

37. MODE Configures a system device.

38. MORE Displays output one screen at a time.

39. MOVE Moves one or more files. Also renames files and directories.

40. MSAV Scans your computer for known viruses.

41. MEMMAKER Starts the Memmaker program,which optimizes our computer’s memory.

42. MSBACKUP Backs up or restores one or more files from one disk to another.

43. MSD Provides detailed technical information about your computer.

44. NLSFUNC Loads country-specific information.

45. POWER Turns power management on and off.

46. PRINT Prints a text file while you are using other MS-DOS commands.

47. QBASIC Starts the MS-DOS QBasic programming environment.

48. REPLACE Replaces files.

49. RESTORE Restores files that were backed up by using the BACKUP command.

50. SCANDISK Checks a drive for errors and repairs any problems it finds.

51. SETVER Sets the version number that MS-DOS reports to a program.

52. SHARE Installs file-sharing and locking capabilities on your hard disk.

53. SORT Sorts input.

54. SUBST Associates a path with a drive letter.

55. SYS Copies MS-DOS system files and command interpreter to a disk you specify.

56. TREE Graphically displays the directory structure of a drive or path.

57. UNDELETE Restores files previously deleted with the DEL command.

58. UNFORMAT Restores a disk erased by the FORMAT command.

59. VSAFE Continuously monitors your computer for viruses.

60. XCOPY Copies files (except hidden and system files) and directory trees.